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U.S. DEPARTMENT OF THE INTERIOR
U.S. GEOLOGICAL SURVEY
ASSESSMENT OF DEEP CONVENTIONAL AND CONTINUOUS-TYPE
(UNCONVENTIONAL) NATURAL GAS PLAYS IN THE UNITED STATES
by
Thaddeus S. Dyman^, James W. Schmoker^, and David H. Root2
Open-File Report 96-529
This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
!U.S. Geological Survey, P.O. Box 25046, MS 939, Denver, CO 80225
2 U.S. Geological Survey, National Center, MS 956 Reston, VA 20192
Assessment of Deep Conventional and Continuous-type (unconventional) Natural Gas Plays inthe United States
by
Thaddeus S. Dyman, James W. Schmoker, and David H. Root
INTRODUCTIONBecause of depressed worldwide oil prices and the highly mature state of drilling and
production in many United States basins, domestic drilling activity has declined and exploration companies are looking overseas for new prospects. Concurrently, domestic oil production is declining and United States reliance on imported oil is increasing. Even if prices were to increase drastically, it would take several years for domestic exploration to reach previous levels of intensity. When the issue of economics is set aside, many domestic drilling frontiers deserve review. One such frontier is natural gas in deep sedimentary basins (Fig. 1).
The United States is rapidly exhausting its oil reserves, whereas estimates of resources of natural gas remain high. According to the National Petroleum Council (1992), the United States contains nearly 1,300 trillion cubic feet (TCP) of recoverable natural gas resources. In 1995, the U.S. Geological Survey estimated that 939 TCP of technically recoverable natural gas remained to be discovered or was part of reserve appreciation from known fields in the onshore areas and State waters of the United States (U.S. Geological Survey Oil and Gas Resource Assessment Team, 1995).
According to Petroleum Information Corporation's Well History Control System (WHCS) (Petroleum Information Corporation, 1991), more than 16,000 wells have been drilled deeper than 15,000 feet in the United States (Dyman and others, in press). These deep wells are widely distributed and are drilled into rocks of various ages and lithologies, but they represent less than one percent of the more than three million wells drilled in the United States.
Almost one fifth of the total undiscovered natural gas resources of the onshore and offshore United States are estimated to occur below 15,000 feet according to the Potential Gas Committee (1995). For example, one of the most significant exploration plays in the United States is the deep Norphlet Formation (Upper Jurassic) play of the eastern Gulf Coast Basin region (Fig. 1; Appendix A). Geologic and geochemical studies by Rice and others (1992) indicated significant potential for Norphlet and perhaps Upper Jurassic Smackover Formation natural gas reservoirs in the eastern Gulf region. In other deep basins, only a few deep wells have been drilled, and the natural gas potential of deep horizons remains poorly known.
Known deep natural gas reservoirs are distributed throughout many United States basins and occur in widely different geologic environments. However, when the Nation is taken as a whole, deep natural gas reservoirs account for only a small portion of the total natural gas production. According to Dwights Energy Data (1986), 1,998 producing reservoirs existed below 15,000 feet in the United States at the end of 1985. Of the total cumulative natural gas production in the United States (698 TCP; Mast and others, 1989), deep reservoirs accounted for seven percent (50 TCP) of which so-called significant reservoirs accounted for nearly half (22.4 TCP; Table 1; NRG Associates, 1990; Dyman and others, in press). Significant reservoirs are defined as those reservoirs with known recoverable size of at least six billion cubic feet (BCF) of gas. Two-hundred fifty-six known significant reservoirs, as identified by NRG Associates (1990), produce from depths greater than 15,000 feet, and 377 significant reservoirs produce from depths greater than 14,000 ft out of a total of more than 15,000 significant reservoirs in the United States (Table 1).
In this report, deep reservoirs are defined as those occurring at or below 15,000 feet; however, a single producing interval may extend both above and below 15,000 feet. For this reason, NRG data in Table 1 were summarized for all producing reservoirs below 14,000 feet in order to capture all reservoirs potentially occurring at or below the 15,000-ft level. Nearly three quarters of these reservoirs produce natural gas. These reservoirs occur in the Gulf Coast,
Permian, Anadarko, Williston, San Joaquin, Ventura, Cook Inlet, and Rocky Mountain basins (Figs. 1 and 2; Table 1).
One-hundred sixty two deep conventional and 11 continuous-type unconventional plays were defined for the U.S. Geological Survey 1995 National Petroleum Assessment (Gautier and others, 1995). One-hundred one of the conventional plays and six of the unconventional plays demonstrate potential for undiscovered technically-recoverable non-associated natural gas (Table 2; Appendix A).
Deep natural gas resources are described and assessed here for three primary reasons: (1) Natural gas may form in the deep central portions of basins and migrate into shallower regions where it is trapped. An understanding of deep basin processes may aid in understanding the occurrence of natural gas in shallow basin environments as well as deep ones. (2) The deeper parts of many sedimentary basins have not been adequately drilled, and opportunities for undiscovered accumulations remain good. (3) Economic conditions strongly affect the development of deep reservoirs, and an economic upturn or improved technology could produce conditions appropriate for increased exploration. Therefore, it is very important to maintain a data base of information on deep natural gas resources and reservoirs.
This report describes both conventionally-trapped and continuous-type (unconventional) plays and resources from the 1995 U. S. Geological Survey National Petroleum Assessment (U.S. Geological Survey Oil and Gas Resource Assessment Team, 1995). It contains (1) a description of deep conventional and continuous-type natural gas plays based on geologic data supplied by province geologists; (2) estimates of undiscovered technically-recoverable gas from these plays; and (3) a comparison of other recent deep natural gas assessments with the 1995 U.S. Geological Survey assessment.
Field and reservoir data were taken primarily from the Significant Field File of NRG Associates Inc. (NRG Associates, 1990). The NRG data base contains identification information, and geologic, production, and engineering data for more than 15,000 oil and gas reservoirs in the United States.
Deep plays were compiled from play descriptions supplied by province geologists and are identified in Appendix A. Many of these deep plays have a potential for both undiscovered oil and gas accumulations and are identified accordingly. For detailed discussions of plays and maps illustrating play outlines of all plays discussed in this report, refer to regional or province reports included in the 1995 U.S. Geological Survey National Petroleum Assessment CD-ROM (Gautier and others, 1995).
METHODOLOGY Conventional Plays
The 1995 U.S. Geological Survey National Petroleum Assessment was based on the play concept, where a play is defined as a set of geologically similar discovered and undiscovered accumulations of oil and/or gas (Gautier and Dolton, 1995). A play is not a single drillable prospect but includes several prospects with similar geologic characteristics. It may have an exploration potential for conventional or unconventional accumulations and may be considered either hypothetical (no known discovery history of fields greater than 1 MMBO or 6 BCF) or confirmed (known discovered accumulations). The number of plays in equivalently-sized provinces may vary somewhat based on the manner in which each province geologist interpreted available data and on individual preferences for combining or subdividing geologic attributes. For example, 23 deep conventional plays were identified in the Western Gulf Basin while only five such plays were identified in the Permian Basin. The deep structural gas play of the Permian Basin includes several different reservoirs each of which could be defined as a separate play.
Confirmed plays were analyzed using field-size distributions, numbers of known accumulations, depths to production, and other geologic and production factors. Hypothetical plays were analyzed using geologic analogs or simulation models based on geological, geophysical, and geochemical data. Hypothetical plays were risked if some uncertainty existed as to the occurrence of at least one 1-MMBO or 6-BCFG accumulation. Play risk was expressed as a probability between 0.0 and 1.0 (see Appendix A) based on the product of estimates for
three play attributes: (1) charge, which includes the presence of source rocks, adequate time- temperature history, and migration; (2) presence of reservoir rocks; and (3) trap, including seal integrity and hydrocarbon retention (Gautier and Dolton, 1995).
In the assessment of conventional plays, a Truncated Shifted Pareto (TSP) distribution was used to model the size-frequency distribution of the population of oil and gas accumulations (Houghton and others, 1993). TSP data were combined with available geologic and production data in order to develop hypotheses about undiscovered conventional accumulations within a play and to estimate the sizes and numbers of accumulations remaining to be discovered for each play. Using play probability and other data, the numbers and sizes of undiscovered accumulations were subjected to Monte Carlo simulation to calculate a range of resources. Play-level assessments were subjected to review and compiled into province, regional, and National totals (Gautier and Dolton, 1995).
Small undiscovered accumulations (< 1 MMBO or 6 BGF) in conventional plays were treated separately for 1995 assessment based on extrapolations of numbers of field size classes greater than 1 MMBO or 6 BCF (Root and Attanasi, 1993). This estimate was made at the province level only and was not subdivided by depth interval. Data for small fields are therefore not included in this deep gas assessment.
Because of uncertainties in estimating undiscovered accumulations of oil and gas, estimates were presented as a range of values associated with different probabilities of occurrence for each play. A pessimistic case has at least a 95-percent chance of occurrence, an optimistic case has at least a 5-percent chance of occurrence, and a mean case represents the arithmetical average of all possible outcomes weighted by their probability. Appendix A includes only mean estimates for each play. The full range of estimates can be found in Gautier and others (1995). Resources attributed to reserve additions from known accumulations are not available at the play level but are substantial. Three-hundred twenty-two TCP of gas is identified in 1995 assessment as attributed to reserve appreciation from known fields for all reservoirs at all depths. Reserve additions to known deep fields are therefore not included in this deep gas assessment.
Undiscovered natural gas resources were subdivided into depth slices by using the average of two density functions. One density function is uniform between the minimum and median depth of the play, and between the median and maximum depth of the play. The other density function is linear, increasing from the minimum to the median depth and linear, decreasing from the median to the maximum depth with a discontinuity at the median. The result of this computation was a fraction of the total resource in 5,000-ft-thick depth slices. The greater-than 15,000 ft depth interval was represented as a single fraction.
Continuous-type PlaysContinuous-type plays were treated as a separate category in the 1995 National Petroleum
Assessment and were assessed using a specialized methodology developed by the U.S. Geological Survey (Schmoker, 1995). These continuous-type plays are geologically diverse and fall into the following categories: coal-bed gas, some biogenic gas occurrences, fractured gas shales, and basin-centered natural gas accumulations. Only continuous-type basin-centered gas plays comprise significant future undiscovered resources in deep sedimentary basins.
Continuous-type accumulations identified in this report are not significantly affected by oil/water or gas/water contacts (Schmoker, 1995); therefore, the methodology used for assessing discrete accumulations of conventional plays is not appropriate here. Continuous-type accumulations are essentially large, potentially productive areas that cannot be defined in terms of discrete units with down-dip hydrocarbon-water contacts. The definition of continuous-type accumulations is based on geology rather than on government regulations defining tight gas.
The assessment of continuous-type plays is based on the concept that an accumulation can be regarded as a collection of hydrocarbon-bearing cells. In the play, cells represent spatial subdivisions defined by the drainage area of wells. Cells may be productive, nonproductive, or untested. Geologic risk, expressed as play probability, was assigned to each play. The number of untested cells in a play, and the fraction of untested cells expected to become productive (success ratio) were estimated, and a probability distribution was defined for estimated ultimate
recovery (EUR) for those expected to become productive cells. The combination of play probability, success ratio, number of untested cells, and EUR probability distribution yielded potential undiscovered resources for each play. Resources were assigned to 5,000-ft. depth slices in the same way as conventional plays.
DEEP UNDISCOVERED NATURAL GAS PLAYS AND RESOURCESAppendix A contains information on deep conventional plays including province and play
name, play classification as hypothetical or confirmed, depth range, fractional distribution of gas, and undiscovered conventional resources. Table 2 identifies play name, minimum, median, and maximum depth, and undiscovered resources for six continuous-type plays assessed in the U.S. Geological Survey 1995 National Petroleum Assessment. Five additional plays are identified but not assessed due to a lack of geologic information about each of them. Refer to Figure 3 for locations of regions and provinces discussed in the following sections.
The U.S. Geological Survey estimated 55.3 TCF of undiscovered technically-recoverable non-associated gas and associated gas from oil fields for 101 deep conventional plays in the lower-48 states and Alaska onshore and State waters. In addition to these gas-bearing plays, 61 conventional plays are identified in Appendix A but have do not have undiscovered gas resources attributed to them. These plays include those that (1) may contain only negligible associated gas because they are oil plays, (2) were severely risked and no gas was assessed for them, or (3) have maximum depths of 15,000 ft and have no gas resource assigned below that depth. About 83 percent of the deep undiscovered conventional resource, or 45.3 TCF of gas, was assessed from the Gulf Coast and Alaska Regions together (Fig. 4; Appendix A). Approximately half of the estimated undiscovered conventional gas (27.4 TCF) is located in the Gulf Coast region in the Western Gulf Basin and Louisiana-Mississippi Salt Basins petroleum provinces. This deep conventional resource does not include deep resources from small fields (<6 BCF of gas) or reserve appreciation from known fields.
An additional 58.4 TCF of technically-recoverable gas was assessed for six continuous-type plays in the Pacific, Colorado Plateau and Basin and Range, and Rocky Mountain and Northern Great Plains Regions (Fig. 4; Table 2). Four of these plays are in Cretaceous and Tertiary low- permeability sandstone reservoirs in the Greater Green River Basin of Wyoming and are estimated to contain 50 percent of the entire undiscovered deep gas resource estimated for the United States. The disparity in numbers and resources of conventional (101 plays 55.3 TCF) and unconventional continuous-type (six plays-58.4 TCF) plays may be due in part to a lack of data dealing with the distribution of poorly understood "basin-centered" gas accumulations. The five "unassessed" continuous-type plays in Table 5 are part of this "poorly understood" category. Not included in Table 5 are other plays that may exist but were not even defined because of a lack of geologic information. For example, deep plays may exist in basins of interior Alaska, in basins of coastal California, and in basins in the Rocky Mountain Region such as the Crazy Mountains Basin, Raton Basin, and Albuquerque Basin.
The number of deep conventional plays identified decreases with increasing depth. Of the 101 conventional gas-bearing plays, 73 plays have maximum depths ranging from 15,000 to 20,000 feet, whereas 20 have maximum depths ranging from 20,001 to 25,000 feet, and 5 have maximum depths ranging from 25,001 to 30,000+ feet. Three plays exceed 30,000 feet in depth. Seventy gas-bearing plays are confirmed (those having known production from significant reservoirs), whereas, 31 are hypothetical. Nearly 40 percent of the confirmed plays are in the Gulf Coast Region, and about 60 percent of the plays are in the Gulf Coast and Rocky Mountain Regions together. Eighty-five of 101 gas-bearing plays have a fractional distribution for non-associated gas of 0.5 or greater. Thirty-six of these plays are in the Gulf Coast Region. Fifty-nine confirmed plays have more than half of their estimated resources in the form of non- associated gas (a fractional distribution for non-associated gas accumulations of 0.5 or greater). Thirty confirmed conventional deep plays have less than half of their estimated resources in the form of non-associated gas (a fractional distribution for non-associated gas of less than 0.5). Only in the Pacific Region does the number of plays having no chance for undiscovered non-
associated gas accumulations exceed the number of plays in which half or more of their resources are non-associated gas.
REGION 1--ALASKAThe petroleum geology of Alaska is complex in part because of the accretion of exotic
terranes to the ancestral North American cratonic margin (Bird, 1995). Numerous sedimentary basins evolved before, during, and after this accretion process. The Central Alaska Province contains nonmarine rocks in a series of poorly understood basins. The Northern Alaska Province includes large, deep composite basins such as the North Slope Basin, while the Southern Alaska Province includes forearc basins of the Pacific margin, primarily containing thick sequences of Tertiary marine and nonmarine rocks. Alaska provinces are frontier areas with respect to deep drilling.
Deep Conventional PlaysThe three Alaska provinces include 21 deep conventional plays (Fig. 3; Appendix A).
Seven of these plays, six of which are located in northern Alaska, were assessed as containing 17.7 TCP of undiscovered technically-recoverable non-associated gas. Deep undiscovered resources were not estimated to exist in the Central Alaska Province. Northern Alaska has the largest number of plays of the three provinces with 10. Only eight of the 21 plays are confirmed, indicating that Alaska petroleum provinces are relatively undrilled. For Alaska as a whole, the average maximum depth of deep conventional plays exceeds 21,000 feet. The deepest plays in the region are the hypothetical Western Thrust Belt Play (110), and Lisburne, Lisburne Unconformity and Endicott Plays (106, 107, and 108) in northern Alaska, which reach maximum depths of 35,000 and 30,000 feet respectively. Deep conventional plays in Alaska are estimated to contain 17.7 TCP of undiscovered technically-recoverable non-associated gas and 271.4 BCF of associated gas from oil fields (Appendix A; Fig. 4).
Deep Continuous-type PlaysDeep continuous-type plays were not identified or assessed in the Alaska Region.
REGION 2--PACIFIC COASTThe Pacific Coast Region includes Washington, all but the southeastern quarter of Oregon,
and that part of California west of the Sierra Nevada Range (Bird and others, 1995). The geology of the region is complex because of arc-related volcanism and plutonism, subduction, crustal accretion, eruption of flood basalts, and the development of numerous small deep basins. The region is subdivided into 8 geologically distinct provinces containing deep resource potential: Western Washington and Oregon, Eastern Washington and Oregon, Northern Coastal, Sonoma- Livermore Basin, Sacramento Basin, San Joaquin Basin, Central Coastal, and Ventura Basins. Deep plays were not identified for the Los Angeles Basin in the 1995 National Petroleum Assessment. Regions 1 and 2 together have known deep ultimate recoverable gas of 0.3 TCP from deep significant reservoirs found in the NRG Associates Data File (Fig. 2; Table 1).
Deep Conventional PlaysRegion 2 contains 20 deep plays (Fig. 3; Appendix A). Washington and Oregon provinces
are generally gas prone, whereas most California provinces are oil prone. The Sacramento Basin is gas prone and is estimated to contain 94.7 BCF of undiscovered technically-recoverable non- associated gas from two deep plays. Although oil prone, the Ventura Basin is estimated to contain 97.8 BCF of undiscovered technically-recoverable non-associated gas from two Paleogene plays (1301 and 1311). The San Joaquin Basin Province contains the largest number of deep plays with six, although only undiscovered oil was assessed for them.
Eight of 20 plays are hypothetical indicating that the region is relatively immature with respect to deep natural gas exploration. For the region as a whole, the average maximum depth of deep plays is about 18,000 feet. The deepest play is the hypothetical Deep Overpressured Fractured Rocks of West Side Fold and Overthrust Belt Play (1011) of the San Joaquin Basin
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which reaches a maximum depth of 25,000 feet. Other California basins such as the Los Angeles Basin contain deep sedimentary rocks, but no deep conventional plays were assessed for them. The Los Angeles Basin contains one deep oil play but it was not assessed because it is not expected to produce oil fields larger than 1 MMBO. In the Western Oregon and Washington Province, the Puget Lowland Deep Gas (403) and Torino Fuca Basin Gas (404) Plays contain 15.2 BCF of undiscovered non-associated technically-recoverable gas. Deep conventional plays in the Pacific Region contain 208.3 BCF of undiscovered technically-recoverable non-associated gas and 341.3 BCF of associated gas from oil fields (Appendix A; Fig. 4).
Deep Continuous-type PlaysOnly one deep continuous-type play was assessed in the Pacific Region: the Columbia
Basin-Basin-Centered Gas Play (503) in the Eastern Oregon-Washington Province (Table 2). This play underlies Tertiary Columbia River basalts in central and eastern Washington. The play is sparsely drilled. The top of an overpressured interval ranges in depth from more than 8,000 to more than 12,000 feet and may be as much as 6,400 feet thick (B.E. Law, in Schmoker and Oscarson, 1995). Play 503 contains 2.6 TCP of deep undiscovered technically-recoverable gas (Table 2).
Two additional continuous-type plays, the Willamette-Puget Sound Basin-Centered Gas Play (412) of the Western Oregon-Washington Province, and the Deep, Overpressured Fractured Rocks of the Central Syncline Play (1408) of the Los Angeles Basin were identified in Table 2, but not assessed, because of a lack of available geologic information.
REGION 3--COLORADO PLATEAU AND BASIN AND RANGEThe Colorado Plateau and Basin and Range Region includes nine petroleum provinces in
Nevada, Idaho, Arizona, eastern California, southeastern Oregon, western and southern Utah, southwestern Colorado, and western New Mexico (Fig. 3; Peterson and Grow, 1995). The geology of the region is typified by Late Precambrian to Early Paleozoic passive continental- margin sedimentation dominated by more than 30,000 feet of shallow-water carbonate and clastic rocks. This continental margin was subjected to repeated compression and plutonism during the Late Paleozoic and Late Mesozoic culminating in Sevier-style tectonism during the Late Cretaceous. The Colorado Plateau part of the region has remained tectonically stable since the Paleozoic, but the Basin and Range was tectonically partitioned into numerous non-marine basins during the Tertiary. The entire region has a fair potential for undiscovered deep natural gas accumulations. Region 3 has no deep significant reservoirs in the NRG Associates Data File (Fig. 2; Table 1).
Deep Conventional PlaysThe Colorado Plateau Basin and Range Region contains 22 deep plays. Nine of 22 plays
have potential for undiscovered technically-recoverable non-associated gas at or below 15,000 feet (Appendix A). In 11 plays, the gas fraction is 0.5 or greater. Plays are relatively equally distributed among the provinces. Only two of 22 plays, both in the Paradox Basin, are confirmed indicating that the deeper parts of most of the region are relatively undrilled. For the region as a whole, the average maximum depth of deep conventional plays is about 19,000 feet. The deepest plays, each reaching maximum depths of 25,000 feet, are in the Snake River Downwarp Province (Older Tertiary Play-1704), Western Great Basin Province (Neogene Source Rocks, Northwestern Nevada and Eastern California Play-1805, and Permian-Triassic Source Rocks Northwestern Nevada and East Central and Eastern Oregon Play 1803), and Southern Arizona Southwestern New Mexico Province (Alamo Hueco Basin Play 2501). Deep conventional plays in the Colorado Plateau Basin and Range Region contain 127.0 BCF of undiscovered technically-recoverable non-associated gas and 2.7 BCF of associated gas from oil fields (Appendix A; Fig. 4).
Deep Continuous-type Plays
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Only one deep continuous-type gas play, the Deep Synclinal Uinta Mesaverde Play (2020) in the Uinta-Piceance Basin, was assessed in the Colorado Plateau-Basin and Range Region. This play is defined on the occurrence of gas-charged, low-permeability Late Cretaceous sandstones of the Mesaverde Group. The play is entirely below 15,000 feet and underlies conventional plays in overlying Tertiary rocks. The play contains an estimated 570 BCF of deep undiscovered technically-recoverable gas (Fig. 4).
REGION 4--ROCKY MOUNTAINS AND NORTHERN GREAT PLAINSThe Rocky Mountains and Northern Great Plains Region contains eight provinces with deep
gas plays (Fig. 3). Region 4 was part of the western United States cratonic margin during much of the Paleozoic. During Mesozoic and Tertiary time, Laramide- and Sevier-style tectonism disrupted the cratonic margin. Laramide structural basins may be very deep (Hanna Basin of the Southwestern Wyoming Province extends to more than 40,000 feet) and are gas prone (Spencer, 1995). Basins in the Rocky Mountains and Northern Great Plains Region have a known recoverable resource of 2.2 TCF of gas (Fig. 2; Table 1).
Deep Conventional PlaysThe Rocky Mountains and Northern Great Plains Region contains 29 deep plays in eight
provinces (Appendix A). Eighteen are predominantly deep gas plays (gas fraction equals or greater than 0.5), and only four of 18 plays have no non-associated gas potential (gas fraction equals 0.0). Two of these are in the Powder River Basin Province. Deep plays are relatively equally distributed throughout the region, but the Wyoming Thrust Belt Province and Southwestern Wyoming Province each contain the most, with six plays each. Nineteen of 29 deep plays are confirmed indicating that the region is relatively mature with respect to deep drilling. The average maximum depth of all deep plays within the region is about 18,900 feet. The deepest plays (Basin Margin Anticline and Subthrust Plays of Southwestern Wyoming Province; plays 3705, 3706) extend to 30,000 feet. Other Rocky Mountain basins containing deep sedimentary rocks such as the Raton Basin are not included here because deep conventional plays were not defined for them in the U.S. Geological Survey 1995 National Petroleum Assessment. Deep conventional plays in the Rocky Mountains and Northern Great Plains Region are estimated to contain 1.9 TCF of undiscovered technically-recoverable non-associated gas and 86.9 BCF of associated gas. Nearly half of this resource is in one play, the Moxa Arch Extension Play (3601) of the Wyoming Thrust Belt Province (Appendix A; Fig. 4).
Deep Continuous-type PlaysFour deep continuous-type plays were assessed for the Rocky Mountain Region (Table 2).
All four plays are in the Greater Green River Basin and occur in Cretaceous or Tertiary rocks as low-permeability basin-centered gas accumulations. Together they contain 55.2 TCF of undiscovered technically-recoverable gas, nearly one-half of the entire deep undiscovered technically-recoverable gas resource of the United States (Fig. 4). More than 90 percent of this resource (50.8 TCF) was estimated for the Cloverly-Frontier (3740) and Mesaverde (3741) Plays alone.
Two additional continuous-type plays, the Big Horn Basin Basin-Centered Gas Play (3404), and the Wind River Basin Basin-Centered Gas Play (3505) were identified in Table 2, but not assessed, because of a lack of available geologic information.
REGION 5--WEST TEXAS AND EASTERN NEW MEXICOProvinces within Region 5 have produced hydrocarbons for many years and include plays
with deep undiscovered natural gas accumulations (Fig. 3). During the Early Paleozoic, a thick shallow-water carbonate sequence was deposited in the region. Early Pennsylvanian deformation attributed to the Ouachita Orogeny trapped oil and gas in complex structural and stratigraphic traps. The Late Pennsylvanian through Permian sequence is composed of mixed clastic and carbonate rocks primarily in stratigraphic and combination traps. The region is geographically dominated by the Permian Basin (Ball and others, 1995). Forty-five percent of
the known ultimate recoverable deep natural gas resource identified for significant reservoirs (15.1 TCP) in the United States occurs in the Permian Basin (Fig. 2; Table 1).
Deep Conventional PlaysRegion 5 contains six deep plays in two petroleum provinces, all but one of which contain
conventional undiscovered technically-recoverable non-associated gas resources (Appendix A). All six plays contain non-associated gas potential, but the Pre-Pennsylvanian Delaware-Val Verde Basins Play (4401) and the lower Pennsylvanian (Bend) Sandstone Play (4404) have fractional distributions favoring gas accumulations. The Pre-Pennsylvanian Delaware Val Verde Basins Play (4401) contains the most deep significant reservoirs and the largest conventional non-associated gas potential. All six plays are confirmed and together range from 15,500 to 24,000 feet in maximum depth. These deep plays are primarily structural plays and include many different stratigraphic units, whereas the many shallower plays in the region are stratigraphic, and generally are defined on the basis of known stratigraphic units. These deep conventional plays are estimated to account for 4.7 TCP of undiscovered technically-recoverable non-associated gas and 6.3 BCF of associated gas from oil fields (Appendix A; Fig. 4).
Deep Continuous-type PlaysDeep continuous-type plays were not identified or assessed for the West Texas Eastern
New Mexico Region.
REGION 6--GULF COASTThe Gulf Coast Region includes the States and State waters that border the Gulf of Mexico
and extends northward to folded Paleozoic rocks of the inland fold belts (Schenk, 1995). The region represents the southern passive continental margin of North America and includes the Western Gulf Basin, East Texas Basin, Louisiana-Mississippi Salt Basins, and Florida Peninsula Provinces (Fig. 3). Since a Triassic rifting event, the region has experienced extensive sedimentation, progradation, and subsidence. The region is geologically complex because of rapid facies changes due to marine transgressions and regressions, and gravity and salt tectonism. Mesozoic strata are dominated by mixed carbonate and clastic sequences, while Cenozoic strata are dominated by clastic sequences. The Gulf Coast Region has been extensively drilled and is the foremost petroleum-producing region of the United States. Thirty-nine percent of the known ultimate recoverable natural gas resources (12.8 TCP; Table 1; Fig. 2) in deep significant reservoirs occurs in the Gulf Coast Region.
Deep Conventional PlaysThe distribution of deep plays in the Gulf Coast Region is very similar to the distribution of
known deep production. Nearly all of the plays have significant reservoirs; only six of 44 plays are hypothetical, indicating that the region is mature with respect to deep drilling (Appendix A). The Gulf Coast Region exceeds all other regions in numbers of deep plays, in part because of the extensive area of sediments deeper than 15,000 feet. Thirty-six plays are predominantly gas plays, and only five plays contain no potential for non-associated gas. These five oil plays are generally updip equivalents of deeper natural gas plays. The Western Gulf Province contains the most plays, and the Florida Peninsula Province contains the least. The average maximum depth of all deep plays in the region is nearly 20,000 feet. The two deepest plays, Norphlet Mobile Bay Deep Gas (4903) and Norphlet Southeast Margin Jackson Dome Flank Deep Gas (4907), extend to 24,000 feet.
The 44 plays in the Gulf Coast Region can be grouped on the basis of the stratigraphic or structural character of each play. For example, the four deep Smackover plays in the Louisiana- Mississippi Salt Basins Province are defined by their structural origin (such as Jackson Dome). Deep conventional plays in the Gulf Coast Region are estimated to account for 27.4 TCF of undiscovered technically-recoverable non-associated gas and 56.3 BCF of associated gas from oil fields (Appendix A; Fig. 4).
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Deep Continuous-type PlaysDeep continuous-type plays were not identified or assessed in the Gulf Coast Region.
REGION 7--MIDCONTINENTThe Midcontinent Region includes all or parts of Oklahoma, Kansas, Nebraska, Texas,
Arkansas, Missouri, Iowa, Minnesota, Wisconsin, and Colorado (Fig. 3; Charpentier, 1995). Geologically, the region represents the Paleozoic continental craton. The deepest basins, the Anadarko and Arkoma, are in the southern part of the region and formed as Early Paleozoic aulacogens. They were later altered tectonically by collisional events along the eastern and southern margin of the United States. In the northern and central parts of the region, Precambrian rifting led to the development of the Midcontinent rift. The region (excluding the Midcontinent rift) has been extensively drilled, but both confirmed and hypothetical deep natural gas plays still possess the potential for undiscovered accumulations.
All of the deep significant production from the NRG Associates Field File in the Midcontinent Region is found in the Anadarko Basin. The Anadarko Basin contains a known ultimate recoverable resource of 2.8 TCP from these deep reservoirs (Table 1; Fig. 2).
Deep Conventional PlaysThe Midcontinent Region includes eight deep plays in the Superior, Anadarko Basin,
Southern Oklahoma, and Arkoma Basin Provinces (Appendix A). All eight plays are classified as predominantly non-associated gas, and six of the eight plays are exclusively gas. The Anadarko and Arkoma Basins Provinces contain most of the plays with three each. Six of the eight plays are confirmed, and the average maximum depth of all deep plays in the region is about 24,000 feet. The Deep Structural Gas Play (5801) in the Anadarko Basin and the Deep Gas Play (6101) in Southern Oklahoma extend to 40,000 feet, and the two deepest wells drilled in the United States, the No. 1 Bertha Rogers and No. 1 Ernest Baden wells in the southern Anadarko Basin, are included in play 5801. Deep conventional plays in the Midcontinent Region are estimated to contain 2.3 TCP of undiscovered technically-recoverable non-associated gas (Appendix A; Fig. 4). The Deep Structural (5801) and Deep Stratigraphic Gas Plays (5812) of the Anadarko Basin contain most of the conventional undiscovered technically-recoverable non- associated gas (2.1 of 2.3 TCP).
Deep Continuous-type PlaysDeep continuous-type plays were not assessed in the Midcontinent Region. One additional
continuous-type play, the Woodford/Chattanooga/Arkansas Novaculite of Midcontinent (5811) was identified in Table 2, but not assessed because of a lack of available geologic information.
REGION 8--EASTERNRegion 8 includes most of the eastern United States in the following provinces: Illinois
Basin, Michigan Basin, Black Warrior Basin, Cincinnati Arch, Appalachian Basin, Blue Ridge Thrust Belt, Piedmont, Atlantic Coastal Plain, Adirondack Uplift, and New England (Fig. 3; Ryder, 1995). The Illinois and Michigan Basins are cratonic basins filled with Paleozoic sedimentary rocks and are underlain by Precambrian rift systems. The Appalachian and Black Warrior Basins are foreland basins recording complex histories of continental rifting, passive margin subsidence, continental collision, and basin subsidence. Up to 40,000 feet of sedimentary rocks are preserved in the eastern Pennsylvania part of the Appalachian Basin. The region has been extensively drilled for petroleum, but deep natural gas plays still possess the potential for undiscovered accumulations. No deep significant fields or reservoirs were identified in the NRG Associates Data File for the Eastern Region.
Deep Conventional PlaysRegion 8 includes 12 deep plays in five provinces: Michigan, Illinois, Black Warrior, and
Appalachian Basins, and Blue Ridge Thrust Belt Province (Appendix A). All 12 plays are predominantly non-associated gas plays, and eight of the 12 plays are entirely gas. The
11
Appalachian Basin Province contains the most plays with five. The Michigan and Illinois Basins and Blue Ridge Thrust Belt Provinces each contain one play. Six of the 12 plays are confirmed indicating that the region is moderately explored with respect to deep drilling. The Precambrian Rift Play (6315) of the Michigan Basin is the deepest play in the region and extends to 30,000 feet. Deep conventional plays in the Eastern Region account for 293.8 BCF of undiscovered technically-recoverable non-associated gas (Appendix A; Fig. 4). About 44 percent of this resource, or 129 BCF, was assigned to the Appalachian Basin.
Deep Continuous-type PlaysDeep continuous-type plays were not identified or assessed in the Eastern Region.
COMPARISON WITH OTHER RECENT NATIONAL ASSESSMENTSThe U.S. Geological Survey estimates that about 113.7 TCP of technically-recoverable
undiscovered gas remains to be discovered from the deeper portions (depths of 15,000 ft and greater) of deep sedimentary basins in the United States. About one-half of this estimated resource (58.4 TCF; Table 3) is attributed to six continuous-type unconventional plays in the Greater Green River Basin of Wyoming, the Columbia Plateau of Washington, and the Uinta Piceance Basin of Utah. About one-half of the remaining resource (27.4 TCF) occurs in conventional plays of the Gulf Coast Basin, and an additional one-third (17.9 TCF) in Alaska. Only 14 of 101 deep gas-bearing conventional plays are estimated to each contain more than 1 TCF of technically-recoverable undiscovered gas (Appendix A).
Table 3 lists undiscovered natural gas resources by region for four recent National petroleum assessments for which data are available at the regional level (refer also to Fig. 5). Totals include technically-recoverable conventional and unconventional resources and both non-associated and associated gas from oil fields below 15,000 feet. Bear in mind that each estimating group used different assessment methodologies and procedures including: geographic areas of coverage, entities assessed, definition of conventional versus unconventional resources, affiliation of province and regional experts, quantitative probability distributions and aggregations, assessment review process, method of subdividing resources by depth interval, and sources of data. For example, the Gas Research Institute (GRI) estimates include reserve growth for existing fields in their totals which have not been subdivided in their published reports. Other estimators reported totals for reserve growth separately. Refer to Dyman and Schmoker (in press) for a detailed discussion of the many areas in which these National petroleum assessments are different.
The GRI and National Petroleum Council (NPC) assessments were based on the GRI Hydrocarbon Supply Model, whereas the U.S. Geological Survey and Potential Gas Committee (PGC) assessments were based on a probabilistic analysis of geologically-based plays. The GRI total does not include Alaska deep gas because GRI did not subdivide Alaska data by depth. The GRI estimate, therefore, should be considered a minimum one. The NPC did not assess Alaska, and the PGC estimated only negligible gas in Alaska basins. Even if Alaska is excluded, the GRI estimate is still the largest (184 TCF; Fig. 5; Table 3).
Regional comparisons indicate significant differences in results. Even though the GRI estimate was the highest of the four groups, regional estimates, with the exception of the Gulf Coast Basin, are relatively low when compared to those of the other groups (Fig. 5). The U.S. Geological Survey Midcontinent Region estimate is noticeably low when compared to the others. Conversely, the U.S. Geological Survey Rocky Mountain Region estimate is noticeably high because of the inclusion of unconventional continuous-type plays (55.2 TCF). Variations in regional totals are partly due to differences in the way in which regions were defined geographically.
POTENTIAL ADDITIONAL RESOURCES AND AREAS OF FUTURE STUDYAn analysis of the U.S. Geological Survey 1995 National Oil and Gas Resource
Assessment reveals many areas for future study, some of which could result in greater estimates of undiscovered deep gas resources. One such area involves re-evaluating and assessing existing conventional and continuous-type plays that were too poorly understood to assess in 1995. For
12
the 1995 assessment, five deep continuous-type plays were identified but not assessed because of a lack of basic geologic and petroleum-related information (Table 2). These basin-centered gas plays could contain significant undiscovered technically-recoverable resources. In addition to these plays, others may exist that were not previously identified. Rocky Mountain basins such as the Raton, Albuquerque, Wind River, and Crazy Mountains Basins, California basins, and the Midcontinent rift are possible areas to investigate.
An additional 61 deep conventional plays are listed in Appendix A, but have no undiscovered non-associated gas resources attributed to them. We feel that it is important to recognize these plays, and have included them in our Appendix. These plays include those that: (1) are oil plays, (2) were severely risked in that no gas was ultimately estimated for them, or (3) have a maximum depth of 15,000 ft and have no gas resource assigned to them below that depth. Fifteen deep conventional oil plays were identified in Appendix A, and gas resources other than associated gas were not estimated for them (gas fraction = 0). An example play in this category is the Cook Inlet Late Mesozoic Oil Play (305). An additional fourteen deep conventional gas plays (gas fraction greater than zero) were highly risked (probability 0.1 or less; Appendix A) and were not assessed. An example play in this category is the hypothetical Older Tertiary Play (1704) of the Idaho Snake River Downwarp Province. Risking hypothetical plays is a subjective process, and assigning even a slightly lower risk (higher probability of resources) based on geologic information could result in additional estimated undiscovered gas resources. Twenty- three deep conventional plays in Appendix A were assigned a maximum play depth of 15,000 feet. Many of these plays are hypothetical gas plays, and depth information for them is poorly known. An example in this category is the Southwest Oregon Eocene Gas Play (410), which is also highly risked (0.1).
Recommendations for future investigations based on results of the U.S. Geological Survey 1995 National Petroleum Assessment include:
1. Re-evaluate the geologic characteristics and drilling histories of existing and potential deep hypothetical plays as more data becomes available. These plays could contribute to estimates of additional deep gas resources as more data becomes available.
2. Conduct geologic studies to determine the spatial relationships between deep conventional and continuous-type plays in some deep basins. Conventionally-trapped deep gas plays may grade into basin-centered, continuous-type gas plays down-dip in the Appalachian, Anadarko, Wind River, and other basins of the United States.
3. Economic analysis of deep gas accumulations, leading to the resource category ofeconomic, technically-recoverable, undiscovered gas. In this way the assessment will be further enhanced by the information necessary to subdivide resources into short, intermediate, and long-term categories based on economics.
4. Determine the existence and extent of continuous-type plays in basins for which they were not assessed previously. Continuous-type accumulations have been hypothesized for the Appalachian, Anadarko, and other basins (see Table 3).
Even though comparisons are difficult to make due to the many differences in procedures and methods by the different groups, the four estimates provide a range of values that can be used to develop National energy policy decisions.
13
REFERENCESBall, M.M., Henry, M.E., and Perry, W.J., Jr., 1995, Region 5-West Texas and eastern New
Mexico, in Gautier, D.L., Dolton, G.L., Takahashi, K.I., and Varnes, K.L., eds., 1995 National petroleum assessment of United States oil and gas resources on CD-ROM: U.S. Geological Survey Digital Data Series 30.
Bird, K.J., 1995, Region 1-Alaska, in Gautier, D.L., Dolton, G.L., Takahashi, K.I., and Varnes, K.L., eds., 1995 National petroleum assessment of United States oil and gas resources on CD-ROM: U.S. Geological Survey Digital Data Series 30.
Bird, K.J., Northern Alaska province, 1995, in Gautier, D.L., Dolton, G.L., Takahashi, K.I., and Varnes, K.L., eds., 1995 National petroleum assessment of United States oil and gas resources on CD-ROM: U.S. Geological Survey Digital Data Series 30.
Charpentier, R.R., 1995, Region 7 Midcontinent, in Gautier, D.L., Dolton, G.L., Takahashi, K.I., and Varnes, K.L., eds., 1995 National petroleum assessment of United States oil and gas resources on CD-ROM: U.S. Geological Survey Digital Data Series 30.
Dwights Energy Data, 1986, Petroleum Data System (through 1985): Available from Dwights Energy Data Corp., Oklahoma City, OK 73108.
Dyman, T.S., ed., 1992, Geologic controls and resource potential of natural gas in deepsedimentary basins in the United States: U.S. Geological Survey Open-File Report 92- 524, 287 p.
Dyman, T.S., Spencer, C.W., Baird, J., Obuch, R., and Nielsen, D., in press, Geologic characteristics of deep natural gas resources based on data from significant fields and reservoirs, in Dyman, T.S., ed., Geologic controls and resource potential of natural gas in deep sedimentary basins in the United States: U.S. Geological Survey Bulletin 2146.
Dyman, T.S., 1995, Deep natural gas reservoirs and plays in the United States, in Gautier, D.L., Dolton, G.L., Takahashi, K.I., and Varnes, K.L., eds., 1995 National petroleum assessment of United States oil and gas resources on CD-ROM: U.S. Geological Survey Digital Data Series 30.
Dyman, T.S., and Schmoker, J.W., in press, Comparison of National petroleum assessments: U.S. Geological Survey Open-File Report.
Gas Research Institute, 1995, GRI baseline projection of U.S. energy supply and demand 1996 edition: Gas Research Institute, 71 p.
Gautier, D.L., and Dolton, G.L., 1995, Methodology for assessment of undiscovered conventional accumulations, in Gautier, D.L., Dolton, G.L., Takahashi, K.I., and Varnes, K.L., eds., 1995 National petroleum assessment of United States oil and gas resources on CD-ROM: U.S. Geological Survey Digital Data Series 30.
Gautier, D.L., Dolton, G.L., Takahashi, K.I., and Varnes, K.L., eds., 1995 Nationalassessment of United States oil and gas resources results, methodology, and supporting data: U.S. Geological Survey Digital Data Series 30.
Houghton, J.C., Dolton, G.L., Mast, R.F., Masters, C.D., and Root, D.H., 1993, U.S. Geological Survey estimation procedure for accumulation size distributions by play: American Association of Petroleum Geologists Bulletin: v. 77, no. 3, p. 454-466.
Mast, R.F., Dolton, G.L., Crovelli, R.A., Root, D.H., Attanasi, E.D., P.E. Martin, L.W. Cooke, G.B. Carpenter, W.C. Pecora, and M.B. Rose, 1989, Estimates of undiscovered conventional oil and gas resources in the United States-a part of the Nation's energy endowment: U.S. Geological Survey and Minerals Management Service special publication, 44 p.
National Petroleum Council, 1992, The potential for natural gas in the United States-executive summary: National Petroleum Council, 24 p., with appendices.
NRG Associates Inc., 1990, The significant oil and gas fields of the United States (throughDecember 31, 1988): Available from Nehring Associates, Inc., P.O. Box 1655, Colorado Springs, CO 80901.
Peterson, J.A., and Grow, J.A., 1995, Colorado Plateau and Basin and Range, in Gautier, D.L., Dolton, G.L., Takahashi, K.I., and Varnes, K.L., eds., 1995 National petroleum
14
assessment of United States oil and gas resources on CD-ROM: U.S. Geological Survey Digital Data Series 30.
Petroleum Information Corporation, 1991, Well History Control System (through December 1991): Available from Petroleum Information Corporation, 4100 East Dry Creek Road, Littleton, CO 80122.
Potential Gas Committee, 1995, Potential Supply of natural gas in the United States: Potential Gas Agency, Colorado School of Mines, Golden, CO., 130 p.
Rice, D.D., Schenk, C.J., Schmoker, J.W., Fox, I.E., Clayton, J.L., Dyman, T.S., Higley, D.K., Keighin, C.W., Law, B.E., and Pollastro, R.M., 1992, Potential for deep natural gas resources in eastern Gulf of Mexico, in Malone, R.D., Shoemaker, H.D., and Byrer, C.W., eds., Proceedings of the natural gas research and development contractors review meeting: U.S. Department of Energy, Morgantown Energy Technology Center Report 92/6125, p. 151-166.
Root, D.H., and Attanasi, E.D., 1993, Small fields in the National oil and gas assessment: American Association of Petroleum Geologists Bulletin, v. 77, no. 3, p. 485-490.
Ryder, R.T., 1995, Region 8-Eastern, 1995, in Gautier, D.L., Dolton, G.L., Takahashi, K.I., and Varnes, K.L., eds., 1995 National petroleum assessment of United States oil and gas resources on CD-ROM: U.S. Geological Survey Digital Data Series 30.
Schenk, C.J., 1995, Region 6~Gulf Coast, in Gautier, D.L., Dolton, G.L., Takahashi, K.I., and Varnes, K.L., eds., 1995 National petroleum assessment of United States oil and gas resources on CD-ROM: U.S. Geological Survey Digital Data Series 30.
Schmoker, J.W., 1995, Method for assessing continuous-type (unconventional) hydrocarbon accumulations, in Gautier, D.L., Dolton, G.L., Takahashi, K.I., and Varnes, K.L., eds., 1995 National petroleum assessment of United States oil and gas resources on CD-ROM: U.S. Geological Survey Digital Data Series 30.
Schmoker, J.W., and Oscarson, S.A., 1995, Descriptions of continuous-type (unconventional) plays of the U.S. Geological Survey 1995 National assessment of United States oil and gas resources: U.S. Geological Survey Open-File Report 95-75B, 44 p.
Spencer, C.W., 1995, Region 4 Rocky Mountains and northern Great Plains, in Gautier, D.L., Dolton, G.L., Takahashi, K.I., and Varnes, K.L., eds., 1995 National petroleum assessment of United States oil and gas resources on CD-ROM: U.S. Geological Survey Digital Data Series 30.
Takahashi, K.I., and Cunningham, K.I., 1987, Map showing wells drilled for oil and gas deeper than 15,000 feet (about 4,600 m) in the conterminous United States and offshore: U.S. Geological Survey Oil and Gas Investigations Map OM-220, scale 1:5,000,000.
U.S. Geological Survey National Oil and Gas Resource Assessment Team, 1995, 1995 National assessment of United States oil and gas resources: U.S. Geological Survey Circular 1118, 20 p.
Vidas, E.H., Hugman, R.H., and Haverkamp, D.S., 1993, Guide to the hydrocarbon supply model: 1993 update: Gas Research Institute Strategic Planning and Analysis Division 93/0454, 250 p.
Woods, T.J., 1993, The long-term trends in U.S. gas supply and prices: 1993 edition of the GRI baseline projection of U.S. energy supply and demand to 2010: Gas Research Institute, 92 p.
Tabl
e 1.
Sum
mar
y of
sig
nific
ant r
eser
voirs
equ
al to
or g
reat
er th
an 1
4,00
0 fe
et in
dep
th in
maj
or d
eep
basi
n ar
eas
of U
.S.
Bas
ed o
n da
ta fr
om
NR
G A
ssoc
iate
s Si
gnifi
cant
Fie
ld F
ile (
NR
G A
ssoc
iate
s, 1
990)
and
com
pile
d in
Dym
an (
1995
). Si
gnif
ican
t res
ervo
irs c
onta
in u
ltim
ate
reco
vera
ble
reso
urce
s gr
eate
r tha
n 6
BC
F of
gas
(eq
uals
1 M
MB
O).
Rec
.= r
ecov
erab
le; r
es.=
rese
rvoi
rs; t
otal
of o
f 377
res
ervo
irs u
sed
for U
.S.
Cum
ulat
ive
prod
uctio
n an
d kn
own
reco
vera
ble
natu
ral g
as in
trill
ions
of c
ubic
fee
t (TC
P). C
umul
ativ
e ga
s= c
umul
ativ
e na
tura
l gas
pro
duct
ion
thro
ugh
1988
; kno
wn
rec.
= kn
own
reco
vera
ble
natu
ral g
as (
cum
ulat
ive
prod
uctio
n an
d re
serv
es);
stra
t= s
tratig
raph
ical
ly tr
appe
d re
serv
oirs
; car
b=
carb
onat
e re
serv
oirs
. Per
cent
ages
do
not a
lway
s ad
d up
to 1
00 p
erce
nt d
ue to
roun
ding
.
Loca
tion
Num
ber o
f re
serv
oirs
and
(p
erce
nt o
f tot
al
num
ber)
(377
)
Cum
ulat
ive
gas
prod
uctio
n an
d (p
erce
nt o
f tot
al
gas)
(21
.4 T
CP)
Kno
wn
rec.
ga
s an
d (p
erce
nt o
f to
tal g
as)
(33.
2 TC
F^)
Stra
tigra
phic
an
d lit
holo
gic
info
rm at
ion
Com
men
ts
Roc
ky M
ts
22 (
6)%
Ana
dark
o B
asin
Perm
ian
Bas
in
0.4
(2)%
84 (
22)%
89 (
24)%
2.4(
11)%
12.4
(58
)%
Gul
f Coa
st
174(
46)%
6.
2(29
)%
Bas
in
2.2
(7)%
2.8
(8)%
15.1
(45
)%
12.8
(39
)%
Will
isto
n 5(
1)%
0.
1 (<
!)%
<0
.1 (
<1)9
B
asin
Cal
iforn
ia/
3 (<
!)%
<0
.1 (
<!)%
0.
3 (1
)%
Ala
ska
Jura
ssic
and
Cre
tace
ous
elas
tic re
serv
oirs
and
Pa
leoz
oic
mix
ed c
arb/
clas
tic
rese
rvoi
rs
Mos
tly a
cla
stic
bas
in.
Som
e C
ambr
ian-
Silu
rian
carb
onat
e pr
oduc
tion
Mid
dle
Pale
ozoi
c m
ixed
cl
astic
/car
b. r
eser
voirs
an
d Lo
wer
Pal
eozo
ic
mos
tly c
arbo
nate
res.
Terti
ary
rese
rvoi
rs
mos
tly c
last
ic; J
uras
sic
and
Cre
tace
ous
rese
rvoi
rs
mix
ed c
arbo
nate
/cla
stic
Ord
ovic
ian
Red
Riv
er
dolo
miti
c re
serv
oirs
Terti
ary
clas
tic
rese
rvoi
rs
Dee
p ga
s m
ostly
fro
m
Uta
h-W
yom
ing
thru
st
belt.
Pot
entia
l fr
om
Han
na a
nd W
ind
Riv
er
basi
ns
65%
of r
eser
voirs
pro
duce
fr
om P
enns
ylva
nian
st
rata
67 o
ut o
f 89
rese
rvoi
rs o
ccur
in
Dev
onia
n or
old
er ro
cks.
Pe
rmia
n re
serv
oirs
are
stra
t- ig
raph
ical
ly-tr
appe
d
37%
of d
eep
rese
rvoi
rs a
re
Terti
ary
Stru
ctur
ally
trap
ped
Stru
ctur
al a
nd
stra
tigra
tigra
phic
trap
s
Tabl
e 2.
D
eep
cont
inuo
us-ty
pe g
as p
lays
of t
he U
.S. G
eolo
gica
l Sur
vey
1995
Nat
iona
l Pet
role
um A
sses
smen
t. In
clud
es b
oth
asse
ssed
and
una
sses
sed
play
s w
ith m
axim
um d
epth
s of
15,
000
feet
or g
reat
er.
Mea
n va
lue
of u
ndis
cove
red
gas
reso
urce
s on
ly f
or
that
por
tion
of p
lay
at o
r bel
ow 1
5,00
0 fe
et; i
n bi
llion
s of
cub
ic f
eet (
BC
F).
Min
imum
(m
in),
med
ian
(med
), an
d m
axim
um
(max
) de
pth
for a
sses
sed
play
s in
feet
. R
efer
to S
chm
oker
and
Osc
arso
n (1
995)
for
geo
logi
c de
scri
ptio
n of
eac
h pl
ay.
Prov
ince
num
ber
nam
ePl
av n
ame
(num
ber)
Dep
th
min
m
edU
ndis
cove
red
max
___gas
(B
CF)
04--
Wes
tern
Ore
gon-
Was
h.
05-E
aste
rn O
rego
n-W
ash.
14-L
os A
ngel
es B
asin
20~U
inta
-Pic
eanc
e B
asin
34 B
ig H
orn
Bas
in
35-W
ind
Riv
er B
asin
37--
Sout
hwes
tern
Wom
ing
58-A
nada
rko
Bas
in
Will
amet
te-P
uget
Sou
nd B
asin
-Cen
tere
d G
as (
412)
Col
umbi
a B
asin
-Bas
in-C
ente
red
Gas
(50
3)
Dee
p, O
verp
ress
ured
Fra
ctur
ed R
ocks
of t
he
Cen
tral S
yncl
ine
(140
8)
Dee
p Sy
nclin
al U
inta
Mes
aver
de (2
020)
Bas
in-C
ente
r Gas
(340
4)
Bas
in-C
ente
r Gas
(350
5)
Gre
en R
iver
Bas
in-C
love
rly-F
ront
ier (
3740
) G
reen
Riv
er B
asin
-Mes
aver
de (3
741)
G
reen
Riv
er B
asin
-Lew
is (
3742
) G
reen
Riv
er B
asin
-For
t Uni
on (
3744
)
Woo
dfor
d/C
hatta
noog
a/A
rkan
sas
Nov
acul
ite
ofM
idco
ntin
ent(
5811
)
not a
sses
sed
9,50
0 13
,000
17,5
00
2,63
6
not a
sses
sed
15,0
00
18,0
00
24,0
00
570
not a
sses
sed
not a
sses
sed
11,5
00
17,0
008,
500
15,0
0010
,500
12
,000
9,50
0 10
,200
not a
sses
sed
22,0
00
25,0
0421
,000
25
,848
19,0
00
4,26
517
,000
95
Tota
l58
,418
Tabl
e 3.
Est
imat
es o
f und
isco
vere
d na
tura
l gas
by
regi
on f
or d
epth
s of
15,
000
feet
or
grea
ter f
rom
rec
ent N
atio
nal P
etro
leum
Cou
ncil
(NPC
), Po
tent
ial G
as C
omm
ittee
(PG
C),
U.S
. Geo
logi
cal S
urve
y (U
SGS)
, and
Gas
Res
earc
h In
stitu
te (
GR
I) a
sses
smen
ts.
Dat
a ar
e m
ean
estim
ates
, exc
ept f
or P
GC
col
umn
whe
re th
ey r
epre
sent
mos
t lik
ely
valu
es.
Reg
iona
l bou
ndar
ies
vary
for
eac
h as
sess
men
t. G
as in
bill
ions
of c
ubic
fee
t (B
CF)
. D
ata
incl
ude
asso
ciat
ed g
as f
rom
oil
accu
mul
atio
ns a
nd n
on-a
ssoc
iate
d ga
s. O
nsho
re re
gion
s an
d st
ate
wat
ers
only
. O
nly
tota
l col
umn
avai
labl
e fo
r G
RI
and
PGC
ass
essm
ents
. U
ncon
vent
iona
l gas
her
e pr
imar
ily in
clud
es g
as in
lo
w-p
erm
eabi
lity
(tigh
t) sa
ndst
ones
. U
ndis
cove
red
volu
mes
of g
as u
nder
diff
eren
t cat
egor
ies
may
var
y du
e to
the
way
in w
hich
a
cate
gory
is d
efin
ed.
For
exam
ple,
the
U.S
. Geo
logi
cal S
urve
y es
timat
e in
clud
es c
ontin
uous
-typ
e sa
ndst
ones
bas
ed o
n ge
olog
ic c
riter
ia,
whe
reas
the
PGC
, GR
I, an
d N
PC id
entif
ies
tight
san
dsto
nes
base
d on
Fed
eral
Ene
rgy
Reg
ulat
ory
Com
mis
sion
-des
igna
ted
crite
ria.
Res
ourc
e es
timat
es b
ased
on
curr
ent t
echn
olog
y ca
se o
nly.
Plu
s si
gn (
+) i
ndic
ates
that
GR
I dat
a fo
r Ala
ska
not b
roke
n ou
t by
dept
h an
d no
t inc
lude
d (to
tal G
RI
Ala
ska
reso
urce
is 1
21,4
53 B
CF)
. Let
ter t
indi
cate
s th
at re
sour
ce e
stim
ates
iden
tifie
d fo
r des
igna
ted
regi
on
tabu
late
d el
sew
here
. Ast
eris
k (*
) in
dica
tes
that
GR
I to
tal i
nclu
des
natu
ral g
as a
ttrib
uted
to re
serv
e gr
owth
in e
xist
ing
field
s. G
as
volu
mes
roun
ded
to n
eare
st B
CF.
Ind
ivid
ual e
stim
ates
may
or m
ay n
ot in
clud
e St
ate
offs
hore
wat
ers.
USG
S es
timat
es d
o no
t inc
lude
un
disc
over
ed g
as f
rom
sm
all f
ield
s (le
ss th
an 6
BC
FG).
Reg
ion
Nat
iona
l Pet
role
um
Cou
ncil
(NPC
)19
921
Ala
ska
Paci
ficR
ocky
Mts
.C
olor
ado
Plat
eau
W. T
exas
-E.
New
Mex
.G
ulf C
oast
Mid
cont
inen
tEa
ster
n
Con
ven
tiona
lU
ncon
ven
tiona
lTo
tal
not a
sses
sed
4,25
811
,728
t
12,3
2825
,124
16,4
142,
159
08,
992 t 0
917
5,47
1 0
4,25
820
,721
t
12,3
2826
,041
21,8
852,
159
Pote
ntia
l Gas
U
.S.
Geo
logi
cal
Com
mitt
ee (
PGC
) Su
rvey
(U
SGS)
1995
1 Tota
l 01,
450
36,2
34t t
44,6
0035
,204
12.8
002
1995
1
Con
ven
tiona
l
17,9
36 550
1,94
613
0
4,70
527
,439
2,26
429
4
Unc
onv
entio
nal
02,
636
55,2
12 570 0 0 0 0
Tota
l
17,9
353,
186
55,1
58 700
4,42
627
,404
2,26
429
4
Gas
Res
earc
h In
stitu
te (
GR
I)*
1995
1 Tota
l +4,
916
44,3
03t
32,7
3466
,034
34,1
332,
133
Tota
l72
,011
15
,381
87
,392
130,288
55,264
58,4
18
113,681
184,
253
1 Ref
er to
Nat
iona
l Pet
role
um C
ounc
il (1
992)
, Pot
entia
l Gas
Com
mitt
ee (
1995
), G
autie
r an
d ot
hers
(19
95),
Woo
ds (
1993
), V
idas
and
ot
hers
(19
93),
and
Gas
Res
earc
h In
stitu
te (
1995
) fo
r det
aile
d ex
plan
atio
ns o
f ass
essm
ents
.
18
Blake Plateau basin
Figure 1. Generalized map of conterminous United States and Alaska showing basinscontaining rocks greater than 15,000 feet (about 4,600 m) deep. Shaded areas represent entire basins. WY-UT-DD = Wyoming- Utah-Idaho. Federal offshore areas identified but not discussed in report. Some small areas and basins listed in Appendix A are not identified on the map.
19
Ultimate recoverable production from deep significant fields
Permian basin 45%
Gulf Coast 39%
8%7%\(2-8) (2.2)
Williston basin
Anadarko basin
Rocky Mountain basinsCalifornia &
Alaska basins1%
(0.3)
Figure 2. Pie chart illustrating the distribution of known ultimate recoverable gas from deep significant fields by region in the U.S. Numbers in parentheses represent estimates in trillions of cubic feet of natural gas (TCFG) taken from NRG Associates file for reservoirs below 14,000 feet in the U.S. (NRG Associates, 1990). Percent for each region based solely on NRG Associates data. Small fields not included. Refer to Table 1 for data summary.
20
Figure 3. Map of United States showing province and region boundaries for U.S. Geological Survey 1995 National petroleum assessment (from U.S. Geological Survey National Oil and Gas Resource Assessment Team, 1995).
21
CO LLJ O DC Z> O CO LU DCCO <OQ LU DC LU^> *- ^ ® O <D
PQ D
-> O
Q- c/> LU C LU 2
LU
*
COLU
<LU
60-i
54-
48-
42-
36-
30-
Rocky Mountains & Northern Great Plains
:= 24-
18-
12-
REGION
Figure 4. Histogram illustrating distribution of estimates of deep undiscovered technically- recoverable gas by region in the United States for the 1995 U.S. Geological Survey National assessment of oil and gas resources. Shaded portion included resources attributed to continuous-type plays for each region. Resources include both non- associated gas and associated gas from oil fields. Mean estimate shown. Refer to Table 2 for data summary.
22
70-n
JIB NPC(1992)
H PGC(1995) USGS(1995)
EZ3 GRI(1995)
t = assessed as part of another region
AlaskaN. Gr. Plains Plateau E. N. Mexico
Gulf Coast
Eastern
Figure 5. Histogram illustrating distribution of estimated deep undiscovered technically- recoverable gas by region in the United States for recent National petroleum assessments including the National Petroleum Council (1992), Potential Gas Committee (1995), U.S. Geological Survey (1995), and Gas Research Institute (1995). Resources include both non-associated gas and associated gas from oil fields. Refer to Table 3 for data summary and explanation of differences.
App
endi
x A
. U
ndis
cove
red
tech
nica
lly-r
ecov
erab
le d
eep
gas
reso
urce
s fo
r con
vent
iona
l pet
role
um p
lays
ext
endi
ng to
dep
ths
equa
l to
or g
reat
er th
an 1
5,00
0 fe
et
in th
e U
.S.
Onl
y a
part
of s
ome
play
s oc
curs
bel
ow 1
5,00
0 fe
et.
Play
def
initi
ons
com
pile
d fr
om d
ata
by p
rovi
nce
geol
ogis
ts (
Gau
tier
and
othe
rs,
1995
). C
, co
nfirm
ed p
lay
with
kno
wn
prod
uctio
n; H
, hyp
othe
tical
pla
y; m
in, m
inim
um d
epth
of p
lay;
med
, med
ian
dept
h of
pla
y; m
ax, m
axim
um d
epth
of p
lay;
Pro
b,
the
prob
abili
ty o
f und
isco
vere
d ac
cum
ulat
ions
of a
t lea
st 6
BC
F of
gas
or
1 M
MB
O in
pla
y w
here
pla
y is
hyp
othe
tical
; G
as f
ract
ion,
fra
ctio
nal d
istri
butio
n of
un
disc
over
ed n
on-a
ssoc
iate
d ga
s ac
cum
ulat
ions
exp
ecte
d in
this
pla
y w
here
0.0
indi
cate
s an
oil
play
and
1.0
indi
cate
s a
non-
asso
ciat
ed g
as p
lay.
Bla
nk in
dica
tes
no d
ata
avai
labl
e. R
efer
to T
able
2 f
or u
ndis
cove
red
reso
urce
s in
unc
onve
ntio
nal c
ontin
uous
-type
pla
ys.
Que
stio
n m
ark
indi
cate
s hi
ghly
inte
rpre
tive
or
spec
ulat
ive
data
. Pl
ay n
umbe
rs c
orre
spon
d to
pla
y nu
mbe
rs in
Gau
tier a
nd o
ther
s (1
995)
. N
on-a
ssoc
iate
d ga
s on
ly l
iste
d fo
r por
tion
of p
lay
belo
w 1
5,00
0 fe
et
and
in b
illio
ns o
f cub
ic f
eet.
Whe
re n
on-a
ssoc
iate
d ga
s vo
lum
es a
re z
ero,
pla
y m
ay b
e en
tirel
y an
oil
play
, pla
y m
ay b
e hi
ghly
ris
ked
(res
ourc
es u
nlik
ely)
, or
max
imum
dep
th o
f pla
y is
15,0
00 fe
et a
nd u
ndis
cove
red
reso
urce
s w
ere
allo
cate
d to
sha
llow
er d
epth
s. N
umbe
rs in
par
enth
eses
afte
r reg
ion
and
prov
ince
nam
es
repr
esen
t tot
al u
ndis
cove
red
tech
nica
lly-r
ecov
erab
le c
onve
ntio
nal g
as v
olum
es w
here
firs
t num
ber i
s no
n-as
soci
ated
gas
, sec
ond
num
ber i
s as
soci
ated
gas
from
oi
l fie
lds,
and
third
num
ber
afte
r eq
ual s
ign
(onl
y fo
r reg
ion)
is to
tal g
as (
BC
FG).
Reg
ion
and
Prov
ince
Play
num
ber
and
nam
eSt
atus
Pro
bm
mD
epth
(fee
t) m
edm
axG
as
frac
tion
Non
-ass
oc.
gas
vol.
Reg
ion
1-A
lask
a (1
7,66
4.4;
Nor
ther
n A
lask
a (1
7,58
8.4;
127
.8)
271.
4=17
,935
.8)
102
Turb
idite
103
Bar
row
Arc
h B
eauf
ortia
n10
4 B
arro
w A
rch
Elle
smer
ian
105
Elle
smer
eian
-Bea
ufor
tian
Cla
stic
s10
6 Li
sbur
ne10
7 Li
sbur
ne U
ncon
form
ity10
8 En
dico
tt10
9 Fo
ld B
elt
110
Wes
tern
Thr
ust B
elt
111
East
ern
Thr
ust B
elt
C C C C H H H C H C
1.0
1.0
1.0
1.0
0.5
0.6
1.0
1.0
0.2
1.0
500
1500
2200
2000
9000
8500
9500 100
1000
2000
8000
7000
10000
1000
025
000
2500
025
000
4000
1000
013
000
25000
1500
015
300
2600
030000
30000
30000
25000
35000
2500
0
0.2
0.3
0.0
1.0
1.0
gas
gas
0.8
0.6
0.7
433.
50.
00.
01,
631.
83,
435.
30.
00.
02,
340.
267
9.2
9,06
8.4
to U)
Cen
tral
Ala
ska
(0.0
; 0.
0)
Sout
hern
Ala
ska
(76.
0; 1
43.6
)
201
Cen
tral A
lask
a C
enoz
oic
Gas
H
0.
120
3 C
entra
l Ala
ska
Pale
ozoi
c O
il H
0.
120
4 K
andi
k Pr
e-M
id C
reta
ceou
s St
rata
H
0.
1
301
Ala
ska
Peni
nsul
a M
esoz
oic
H
<0.1
20
0030
2 A
lask
a Pe
nins
ula
Terti
ary
H
<0.1
50
0030
3 C
ook
Inle
t-Bel
uga-
Ster
ling
Gas
C
1.0
2000
304
Coo
k In
let H
emlo
ck-T
yone
k O
il C
1.0
5000
305
Coo
k In
let L
ate
Mes
ozoi
c O
il .
H
<0.1
307
Cop
per R
iver
Mes
ozoi
c O
il >H
<0
.130
8 G
ulf o
f Ala
ska
Yak
atag
a Fo
ld B
elt
H
0.7
030
9 G
ulf o
f Ala
ska
Yak
utat
For
elan
d H
0.
4 16
00
4000
1000
0
1500
0?
gas
1500
0+ o
il 15
000+
gas
?
2000
0 ga
s 15
000+
gas
20
000
1.0
1800
0 0.
0 15
000
oil
1500
0 oi
l 28
000+
oil
2800
0+ o
il
0.0
0.0
0.0
0.0
0.0
76.0
0.
0 0.
0 0.
0 0.
0 0.
0
Prov
ince
nam
e
Reg
ion
2-P
acif
ic
(208
.3;
341.
3=
549.
Wes
tern
Ore
gon
and
Was
hing
ton
(15.
2; 3
.0)
East
ern
Was
hing
ton -
Ore
gon
(0.0
; 0.0
)
Nor
ther
n C
alifo
rnia
Coa
stal
(0.
0; 0
.0)
Sono
ma-
Live
rmor
e B
asin
(0.
6; 0
.1)
Sacr
amen
to B
asin
(94
.7; 0
.0)
San
Joaq
uin
Bas
in (
0.0;
270
.9)
Cen
tral
Coa
stal
Bas
ins
(0.0
; 0.
0)
Ven
tura
Bas
in (
97.8
; 67.
3)
Reg
ion
3-C
olor
ado
Pla
teau
an
d B
asin
Idah
o Sn
ake
Riv
er D
ownw
arp
(2.1
; 0.0
)
Play
num
ber
and
nam
e St
atus
Pro
b
6)40
3 Pu
get L
owla
nd D
eep
Gas
404
Tofin
o-Fu
ca B
asin
Gas
405
Wes
tern
Was
hing
ton
Mel
ange
410
Sout
hwes
t Ore
gon
Eoce
ne G
as
501
Nor
thw
este
rn C
olum
bia
Plat
eau
Gas
703
Sarg
ent/H
ollis
ter O
il an
d G
as
801
Sono
ma-
Live
rmor
e
902
Sout
hern
For
bes-
Kio
ne90
3 W
este
rn W
inte
rs th
roug
h D
omin
gene
1003
Low
er B
aker
sfie
ld A
rch
1004
Wes
t Sid
e Fo
ld B
elt S
ourc
ed b
y Po
st-
Low
er M
ioce
ne R
ocks
1005
Wes
t Sid
e Fo
ld B
elt S
ourc
ed b
y Pr
e-M
iddl
e M
ioce
ne R
ocks
1008
Tej
on P
latfo
rm10
09 S
outh
ern
End
Thr
ust S
alie
nt10
11 D
eep
Ove
rpre
ssur
ed F
ract
ured
Roc
ksof
Wes
t Sid
e Fo
ld a
nd O
verth
rust
Bel
t
11 04
La
Hon
da O
il
1301
Pal
eoge
ne -
Ons
hore
1302
Neo
gene
- O
nsho
re13
04 C
reta
ceou
s13
11 P
aleo
gene
-Off
shor
e St
ate
Wat
ers
and
Ran
ge
(127
.0;
2.7=
12
9.7)
1701
Mio
cene
Lac
ustri
ne (L
ake
Bru
neau
)17
03 P
re-M
ioce
ne17
04 O
lder
Ter
tiary
H H H H H C C H C C C C C C H-
C C C H C H H H
0.1
0.2
0.5
0.1
0.6
1.0
1.0
0.4
1.0
1.0
1.0
1.0
1.0
1.0
cO.l 1.0
1.0
1.0
0.2
0.1
0.1
Dep
th (f
eet)
min
m
ed
1000
050
010
050
0
500
1000
1000
4000
2000
5600 80
0
300
500
2000
1800
0 0
1000 500
5000
4000
1000
0
1500
060
0090
0030
00
8000
2000
6000
8000
7000
8500
9000
9000
6000
9000
1800
7000
8000
7000
6000
1500
0
max
2000
020
000
1800
015
000
1500
0
1500
0
1600
0
2000
016
000
1800
0
1800
0
2200
015
000
1600
0
2500
0
1500
0
2000
020
000
1500
0+15
000+
1500
015
000
2500
0
Gas
fr
actio
n
1.0
1.0
0.0
1.0
1.0
0.5
0.5
1.0
1.0
0.0
0.0
0.0
0.0
0.0
gas
0.0
0.4
0.0
gas?
gas
0.6
0.6
0.9
Non
-ass
oc.
gas
volu
me
13.4 1.8
0.0
0.0
0.0
0.0
0.6
57.2
37.5 0.0
to0.
0 £
0.0
0.0
0.0
0.0
0.0
25.6 0.0
0.0
72.2 2.1
0.0
0.0
Prov
ince
nam
e
Wes
tern
Gre
at B
asin
(1.
2; 0
.0)
East
ern
Gre
at B
asin
(41
.8;
1.7)
Uin
ta-P
icea
nce
Bas
in (
7.9;
1.0
)
Para
dox
Bas
in (
6.5;
0.0
)
Alb
uque
rque
Bas
in-S
ame
Fe R
ift (
50.2
; 0.0
)
Nor
ther
n A
rizon
a (1
7.3;
0.0
)
Sout
hern
Ari
zona
~SW
New
Mex
ico
(0.0
; 0.0
)
Sout
h-C
entra
l New
Mex
ico
(0.0
; 0.0
)
Reg
ion
4-R
ocky
M
ount
ains
(1
,859
.2;
Mon
tana
Thr
ust B
elt (
263.
7; 0
.1)
Play
num
ber
and
nam
e St
atus
Pr
ob
1801
Hor
nbro
ok B
asin
-Mod
oc P
late
au18
03 P
erm
ian-
Tria
ssic
Sou
rce
Roc
ksN
orth
wes
tern
Nev
ada
and
East
Cen
tral a
nd E
aste
rn O
rego
n18
04 C
reta
ceou
s So
urce
Roc
ks, N
orth
w
este
rn N
evad
a18
05 N
eoge
ne S
ourc
e R
ocks
, Nor
thw
este
rnN
evad
a an
d Ea
ster
n C
alifo
rnia
1902
Lat
e Pa
leoz
oic
1905
You
nger
Ter
tiary
Bas
ins
1906
Lat
e Pa
leoz
oic-
Mes
ozoi
c (C
entra
lN
evad
a) T
hrus
t Bel
t19
07 S
evie
r Fro
ntal
Zon
e
2014
Bas
in M
argi
n Su
bthr
usts
2101
Bur
ied
Faul
t Blo
cks,
Old
erPa
leoz
oic
2104
Per
mia
n-Pe
nnsy
lvan
ian
Mar
gina
lC
last
ic21
05 S
alt A
ntic
line
Flan
k
2301
Alb
uque
rque
Bas
in23
05 S
an J
uan
Sag
2403
Lat
e Pr
oter
ozoi
c (C
huar
-Sou
rced
)an
d L
ower
Pal
eozo
ic
2501
Ala
mo
Hue
co B
asin
2502
Ped
rego
sa B
asin
2602
Oro
gran
de B
asin
2603
Mes
illa-
Mim
bres
Bas
ins
86.9
= 1,
946.
1)27
01 I
mbr
icat
e T
hrus
t Gas
2704
Hel
ena
Salie
nt G
as27
06 T
ertia
ry B
asin
s O
il an
d G
as
H H H H H H H H C H C H H H H H H H C H H
0.1
0.2
0.1
0.1
0.2
0.2
0.4
0.1 1.0
0.4
1.0
0.5
0.6
0.3
0.1
0.1
<0.1
<0.1
0.3
0.5
0.3
Dep
th (f
eet)
min
m
ed45
0050
00
4500
4500
3000
3000
6500
6000
6000
3000
3000
8000
3000
6000
1500
5000
2000
5000
3000 500
2000
9000
1000
0
9000
1200
0
8000
1200
012
000
1400
0
9000
7000
5000
1200
070
00
9000
1200
010
000
1000
014
000
1200
090
0080
00
max
1500
025
000
1500
0
2500
0
2000
0
2000
020
000
2000
0
1500
0
2000
015
000
2000
015
000
2000
0
2500
017
000
2400
024
000
1900
020
000
1600
0
Gas
fr
actio
n0.
90.
5
0.1
gas?
0.2
0.0
gas
0.6
0.4
0.8
0.7
0.8
0.0
0.5
0.4
0.4
0.5
0.4
0.95
1.0
0.8
Non
ass
oc.
gas
volu
me
0.0
1.2
0.0
0.0
3.0
4.1
0.0
34.7 7.9 °'°
S
6.5
0.0
50.2 0.0
17.3 0.0
0.0
0.0
0.0
256.
36.
90.
5
Prov
ince
nam
e
Sout
hwes
t Mon
tana
(30
.2;
0.0)
Will
isto
n B
asin
(13
.4;
0.0)
Pow
der R
iver
Bas
in (
0.0;
0.4
)
Big
Hor
n B
asin
(58
.4;
0.0)
Win
d R
iver
Bas
in (
131.
3; 2
.8)
Wyo
min
g T
hrus
t Bel
t (11
61.3
; 61
.0)
Sout
hwes
tern
Wyo
min
g (1
53.2
; 22.
6)
Play
num
ber
and
nam
e St
atus
Pro
b
2901
Cra
zy M
ount
ains
and
Lak
e B
asin
sC
reta
ceou
s G
as29
04 B
earto
oth
Fron
tal O
il an
d G
as29
07 T
ertia
ry B
asin
s O
il an
d G
as
3102
Red
Riv
er (O
rdov
icia
n)31
06 P
ost M
adis
on th
roug
h Tr
iass
icC
last
ic31
07Pr
e-R
edR
iver
Gas
3301
Bas
in M
argi
n Su
bthr
ust
3304
Upp
er M
inne
lusa
San
dsto
ne
3401
Bas
in M
argi
n Su
bthr
ust
3403
Dee
p B
asin
Stru
ctur
e
3501
Bas
in M
argi
n Su
bthr
ust
3503
Dee
p B
asin
Stru
ctur
e35
04 M
uddy
San
dsto
ne S
tratig
raph
ic35
06 P
hosp
horia
Stra
tigra
phic
3601
Mox
a A
rch
Exte
nsio
n36
02 C
raw
ford
-Mea
de T
hrus
ts36
03 N
orth
ern
Thru
sts
3604
Abs
arok
a Th
rust
3606
Hog
sbac
k Th
rust
3607
Cre
tace
ous
Stra
tigra
phic
3701
Roc
k Sp
rings
Upl
ift
3702
Che
roke
e A
rch
3703
Axi
al U
plif
t37
04 M
oxa
Arc
h-L
aBar
ge37
05 B
asin
Mar
gin
Ant
iclin
e37
06 S
ubth
rust
C H H C C C H C H C C C C H C H H C C C C C C C C H
1.0
0.4
0.2
1.0
1.0
1.0
0.4
1.0
0.5
1.0
1.0
1.0
1.0
0.8
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
0.8
Dep
th (f
eet)
min
m
ed
1000
4000 20
0
7000
1000
012
000
5000
5000
5000
8000
5000
1300
5000
2000
1000
045
0045
0050
0060
0010
00
1500
1500
2000
1200
4000
5000
5000
1200
012
000
1300
0
1300
0
1200
085
000
1200
014
000
1200
085
000
1200
011
000
1400
011
000
1000
010
000
1000
080
00
6000
5000
6000
1000
014
000
1200
0
max
2000
020
000
1800
0
1600
0
1600
016
000+
1500
015
000
2000
020
000
2000
024
000
1600
020
000
1800
017
500
1500
018
000
1700
017
000
1800
020
000
1500
018
000
3000
030
000
Gas
fr
actio
n
1.0
0.4
0.8
0.5
1.0
1.0
0.0
0.0
0.3
1.0
0.3
0.9
0.3
0.0
1.0
1.0
0.7
0.8
0.6
0.0
0.8
0.3
0.3
0.7
0.6
0.4
Non
-ass
oc.
gas
volu
me
26.0 2.7
1.5
0.0
0.0
13.4 0.0
0.0
10.1
48.3
32.7
86.8
11.8
&
0.0
953.
048
.7 0.0
118.
740
.8 0.0
18.4
18.4 0.0
45.5
44.3
26.6
Prov
ince
nam
e Pl
ay n
umbe
r an
d na
me
Stat
us
Prob
Reg
ion
5-W
est
Tex
as
and
Eas
tern
N
ew
Mex
ico
(4,6
98.2
; 6.
3=
4,70
4.5)
Perm
ian
Bas
in (
4,40
8.5;
6.3
) 44
01 P
re-P
enns
ylva
nian
, Del
awar
e-V
al V
erde
Bas
ins
4402
Pre
-Pen
nsyl
vani
an, C
entra
lB
asin
Pla
tform
4404
Low
er P
enns
ylva
nian
(B
end)
Sand
ston
e44
06 U
pper
Pen
nsyl
vani
an, N
orth
wes
tern
and
East
ern
Shel
ves,
Nor
ther
nD
elaw
are
and
Mid
land
Bas
ins
and
Nor
ther
n C
entra
l Bas
in P
latf
orm
4412
Del
awar
e Sa
ndst
ones
Mar
atho
n T
hrus
t Bel
t (1 1
.0; 0
.0)
4601
Fro
ntal
Zon
e O
il an
d G
as
Reg
ion
6-G
uIf
Coa
st
(27,
382.
2;
56.3
= 27
,438
.5)
Wes
tern
Gul
f Bas
in (
19,1
08.1
; 6.
4)
4701
Hou
ston
Sal
t Dom
e Fl
ank
Oil
and
Gas
4702
Nor
phle
t Sou
th T
exas
Dee
p G
as47
03 S
mac
kove
r So
uth
Texa
s G
as47
04 C
otto
n V
alle
y W
este
rn G
ulf G
as a
ndO
il47
05 L
ower
Cre
tace
ous
Car
bona
te S
helf/
Shel
f Edg
e G
as a
nd O
il47
09 T
usca
loos
a D
eep
Sand
ston
e G
as47
10 W
oodb
ine
Sout
h A
ngel
ina
Flex
ure
Oil
and
Gas
4720
Low
er W
ilcox
Dow
ndip
Ove
r-pr
essu
red
Gas
4723
Upp
er W
ilcox
Dow
ndip
Ove
r-pr
essu
red
Gas
4724
Mid
dle
Eoce
ne S
ands
tone
s D
ownd
ipG
as47
27 Y
egua
Dow
ndip
Gas
4729
Jac
kson
Dow
ndip
Gas
4731
Vic
ksbu
rg D
ownd
ip G
as47
32 F
rio S
outh
Tex
as D
ownd
ip O
ilan
d G
as
C C C C C C C H C C C C C C C C C H C C
1.0
1.0
1.0
1.0
1.0
1.0
1.0
0.8
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
0.5
1.0
1.0
Dep
th (f
eet)
min
m
ed
8400
4000
8000
5000
5000
3500 25
014
000
1000
0
3000
6000
1200
0
7000
8000
8000
8000
8000
6000
7000
6000
1600
0
1000
0
1100
0
1100
0
1100
0
9000
1800
016
000
1200
0
1400
017
000
1400
0
1600
0
1600
0
1200
014
000
1400
014
000
1200
0
max
2400
0
1550
0
1650
0
1600
0
1600
0
1800
0
1600
022
000
2200
0
2000
0
2000
022
000
2000
0
2000
0
2200
0
1800
022
000
2200
022
000
1800
0
Gas
fr
actio
n
1.0
0.2
0.8
0.2
0.3
0.4
0.6
1.0
1.0
0.7
0.7
1.0
0.3
1.0
1.0
0.9
1.0
1.0
1.0
1.0
Non
-ass
oc.
gas
volu
me
2,33
7.8
0.0
278.
7
23.8
33.7
11.0
34.2
505.
663
5.9
83.0
881.
54,
800.
0
299.
3
1,82
0.4
3,36
8.8
211.
62,
117.
31,
252.
063
9.4
154.
3
Prov
ince
nam
ePl
ay n
umbe
r an
d na
me
Stat
us
Prob
D
epth
(fee
t) G
as
Non
-ass
oc.
_________m
in
med
m
ax
frac
tion
gas
volu
me
Wes
tern
Gul
f Bas
in c
ontin
ued
Lou
isia
na-M
iss.
Sal
t Bas
ins
(8,2
39.0
; 49
.9)
4735
Frio
SE
Texa
s/S.
Lou
isia
na
Mid
-dip
Gas
and
Oil
4736
Frio
SE
Texa
s/S.
Lou
isia
naD
ownd
ip G
as
4738
Ana
huac
San
dsto
ne G
as a
nd O
il47
40 L
ower
Mio
cene
Del
taic
San
dsto
ne
Gas
and
Oil
4741
Low
er M
ioce
ne S
lope
and
Fan
San
d
ston
e G
as47
42 M
iddl
e M
ioce
ne R
uvia
l San
dsto
ne
Gas
and
Oil
4743
Mid
dle
Mio
cene
Del
taic
San
dsto
ne
Gas
and
Oil
4744
Upp
er M
ioce
ne F
luvi
al S
ands
tone
G
as a
nd O
il
4745
Upp
er M
ioce
ne D
elta
ic S
ands
tone
G
as a
nd O
il
4901
Pie
rcem
ent S
alt D
ome
Flan
ks O
il an
d G
as49
03 N
orph
let M
obile
Bay
Dee
p G
as49
04 N
orph
let W
iggi
ns -
Han
cock
Arc
h G
as49
05 N
orph
let S
alt B
asin
Oil
and
Gas
4906
Nor
phle
t Ala
bam
a U
pdip
Oil
4907
Nor
phle
t SE
Mar
gin
Jack
son
Dom
e Fl
ank
Dee
p G
as49
09 S
mac
kove
r Wig
gins
- B
aldw
in F
lank
s G
as49
10 S
mac
kove
r A
laba
ma/
Flor
ida
Perip
hera
l Fau
lt Z
one
Oil
and
Gas
4912
Sm
acko
ver S
alt B
asin
s G
as a
nd O
il49
13 S
mac
kove
r Jac
kson
Dom
e D
eep
Gas
49
18 H
ayne
svill
e Sa
lt B
asin
s G
as a
nd O
il49
20 G
ilmer
Lim
esto
ne G
as49
21 C
otto
n V
alle
y U
pdip
Oil
4922
Cot
ton
Val
ley
Salt
Bas
ins
Gas
49
25 H
osst
on U
pdip
Oil
C
1.0
6000
12
000
1600
0 0.
6 62
.0
C
1.0
8000
14
000
2000
0 1.
0 55
8.8
C
1.0
8000
15
000
2000
0 0.
7 23
6.6
C
1.0
3000
10
000
1600
0 0.
7 44
.1
C
1.0
8000
14
000
2000
0 1.
0 1,
123.
2
C
1.0
1000
10
000
1700
0 0.
8 68
.5
C
1.0
8000
14
000
2000
0 0.
8 13
1.9
C
1.0
1000
80
00
1600
0 0.
4 3.
5
C
1.0
4000
14
000
2000
0 0.
6 96
.8
C C H C H H C C C C C C C C C
1.0
1.0
0.6
1.0
0.5
0.5
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
4000
1700
0
1300
080
0080
00
2000
0
1200
0
1000
08000
20000
6000
1000
02000
8000
4000
1000
020
000
1700
012
000
1200
0
2200
0
1600
0
1500
012
000
21000
1400
014
000
1000
014
000
9000
1600
024
000
2100
017
000
1600
0
24000
2000
0
2000
018
000
2300
020
000
1800
018
000
20000
1600
0
0.7
1.0
1.0
0.0
0.0
1.0
1.0
0.3
0.6
1.0
0.9
1.0
0.0
1.0
0.0
31.9
5,259.6
233.3
213.4
0.0
111.
1
356.5
319.9
180.5
259.8
379.9
367.0
0.0
155.8
0.0
00
Prov
ince
nam
e
Flor
ida
Peni
nsul
a (0
.0;
0.0)
Reg
ion
7-M
idco
ntin
ent
(2,2
64.1
; 0.
0=Su
perio
r (8
5.5;
0.0
)
Ana
dark
o B
asin
(20
67.3
; 0.0
)
Sout
hern
Okl
ahom
a(1
07.8
; 0.0
)
Ark
oma
Bas
in (
3.5;
0.0
)
Reg
ion
Mic
higa
n
Play
num
ber
and
nam
e St
atus
Pr
ob
4926
Hos
ston
/Tra
vis
Peak
Sal
t Bas
ins
Gas
49
29 S
ligo/
Pette
t Sal
t Bas
ins
Gas
49
31 J
ames
Lim
esto
ne G
as
4933
Gle
n R
ose/
Rod
essa
Sal
t Bas
ins
Gas
49
35 P
alux
y D
ownd
ip G
as
5006
Woo
d R
iver
Dol
omite
Dee
p G
as
2,26
4.1)
5101
Pre
cam
bria
n M
idco
ntin
ent R
iftSy
stem
5801
Dee
p St
ruct
ural
Gas
5812
Dee
p St
ratig
raph
ic G
as58
27 W
ashe
s
6101
Dee
p G
as
6205
Arb
uckl
e th
roug
h M
isen
er B
asem
ent
Faul
t and
She
lf G
as62
06 C
rom
wel
l-Spi
ro-W
apan
ucka
Sub-
Cho
ctaw
Thr
ust G
as62
07 C
arbo
nife
rous
Tur
bidi
te T
hrus
t Bel
tG
as
C
C
C
C
C H H C C C C C C H
1.0
1.0
1.0
1.0
1.0
0.1
0.4
1.0
1.0
1.0
1.0
1.0
1.0
0.2
Dep
th (f
eet)
min
m
ed40
00
5000
80
00
3000
40
00
1400
0
5000
1300
013
000
500
1300
0
4000
7000
6000
1200
0 11
000
1100
0 10
000
1000
0
1600
0
1000
0
1700
015
000
9400
1500
0
8000
1200
0
1300
0
max
1800
0 16
000
1600
0 16
000
1600
0
1900
0
2500
0
4000
030
000
1500
0+
4000
0
1500
0
1500
0
2000
0
Gas
fr
actio
n1.
0 1.
0 ga
s?
1.0
1.0
oil?
0.6
1.0
1.0
0.8
1.0
1.0
1.0
1.0
Non
-ass
oc.
gas
volu
me
240 16
61 52
0 0 85
.8
.2
.0
.3
.0 .0 .5
770.
01,
297 0
107 0 0 3.3 .0 .8 .0 .0 .5
8-E
aste
rn
(293
.8;
0.0=
29
3.8)
Bas
in (
0.0
Illin
ois
Bas
in (
102.
7
Bla
ck W
arrio
r Bas
in
;0.0
)
;0.0
)
(61.
5,0.
0)
6315
Pre
cam
bria
n R
ift
6405
Illi
nois
Bas
in -
Rou
gh C
reek
Gra
ben
6501
Cam
bria
n an
d O
rdov
icia
n C
arbo
nate
6502
Upp
er M
issi
ssip
pian
San
dsto
ne65
03 P
enns
ylva
nian
San
dsto
ne65
05 D
evon
ian
Che
rt an
d C
arbo
nate
H H H C C H
0.1 1.0
1.0
1.0
1.0
0.8
1000
0
4500
1000
2500
1500
2000
2000
0
1200
0
1000
080
0070
0080
00
3000
0
1900
0
2500
016
000
1500
018
000
1.0
1.0
0.8
0.8
1.0
1.0
0
102 42 14 0 5.0 .7 .3 .1 .0 .1
Prov
ince
nam
ePl
ay n
umbe
r an
d na
me
Stat
us
Prob
D
epth
(fee
t) G
as
Non
-ass
oc.
________m
in
med
m
ax
frac
tion
gas
volu
me
App
alac
hian
Bas
in (
129.
6; 0
.0)
Blu
e R
idge
Thr
ust B
elt (
0.0;
0.0
)
6701
Rom
e Tr
ough
6702
Upp
er C
ambr
ian,
Ord
ovic
ian,
an
d L
ower
/Mid
dle
Sulu
rian
Thru
st
Bel
t67
03 B
eekm
anto
wn/
Kno
x C
arbo
nate
O
il/G
as67
04 R
ose
Run
/Gat
esbu
rg/T
here
sa S
and
st
one
Gas
6706
Tre
nton
/Bla
ck R
iver
Car
bona
te O
il an
d G
as
6801
Sou
ther
n A
ppal
achi
ans
Sub-
Thru
st
Shee
t
H
0.8
6000
10
000
2500
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