Formation Code or Reservoir Name - LMKR · IHS provides production data by both Formation Code and...

FORMATION CODE OR RESERVOIR NAME?

Production by Formation Code or Reservoir Name? Author: Larry J. Rairden, Nova Geoscience - January 13, 2012

IHS provides production data by both Formation Code and Reservoir Name.

Either format can be imported into GeoGraphix projects. In regional projects,

production by Formation Code (default option) is commonly preferred. In the case of

individual field studies, however, it is often useful to load production by Reservoir

Name. In any case, the two formats must not be commingled within a single

GeoGraphix project.

Regional studies must be able to aggregate productive formations or zones

across an extensive area, while studies at the field-level must identify and segregate

individual units of a productive formation. The examples below review production in

Hidalgo County, Texas, and in particular, a recent discovery on the flank of McAllen

Ranch Field.

McAllen Ranch Field has produced over 1 TCF gas since its discovery in 1960.

Production is from Vicksburg (Oligocene) sands ranging in depth from 9,200 to nearly

16,000 feet. In the 1980's, an 800-acre extension of this field was discovered in an area

surrounded by dry holes and marginal wells. The particular Vicksburg unit composing

this 150 BCFG discovery was identified by the operator as the Guerra sand.

Production by Formation Code

In the first example, a new project is set up and well data is imported for all of

Hidalgo County via the IHS 298 Production Import wizard. In the second screen of this

wizard, the import file is specified and default options are selected (Figure 1). By

default, production is loaded by Formation Code.


Figure 1: IHS 298 Production Wizard default is Formation Code

In this example, the Guerra 47 (42215322890000) contains production from only

one formation, with Zone Alias VKBG, though there are several sets of perfs. Production

and perfs can be summarized by the Well Summary Tool (Figure 2).


Figure 2: Well Summary (Well ID 42215322890000) showing four sets of perfs and production from the

VKBG zones.


In WellBase, monthly production for this well is viewed on the "Production" tabbed

page (Figure 3). Cumulative production is displayed as 5.7 BCFG and 86 MBO.

Figure 3: WellBase showing production tabbed page for Well ID 42215322890000.

Production by Formation Code facilitates regional mapping. In this example, the

primary producing formations of Hidalgo County, the Frio and Vicksburg, can be easily

differentiated by bubble maps (Figures 4 and 5).


Figure 4: Bubble map of VKBG production in Hidalgo County, TX.


Figure 5: Bubble map of FRIO production in Hidalgo County, TX.


Production by Reservoir Name

In the second workflow example, a new project is set up and well data is

imported via the IHS 298 Production Import wizard. In this case, the import option "Use

Reservoir Name instead of Formation Code" is selected in the second screen of this

wizard (Figure 6).


Figure 6: IHS 298 Production Wizard with Reservoir Name selected

In this example, the Guerra 47 has production from two intervals with Zone

Alias's GUERRA and VICKSBURG Y EAST. These can be summarized by the Well Summary

Tool (Figure 7).

Figure 7: Well Summary (Well ID 42215322890000) showing perfs and production from the VICKSBURG Y

EAST and GUERRA zones.


In WellBase, monthly production for this well is viewed on the "Production"

tabbed page (Figure 8). Cumulative production is again shown as 5.7 BCFG and 86 MBO.

Figure 8: WellBase view of Well ID 42215322890000 showing first 18-months production.

Reservoir names generally come from regulatory filings submitted by operators.

These reservoir names may be specific to the operator, the producing field, or perhaps

the fault block containing the well. As such, reservoir names can change from field to

field, from operator to operator, or from fault block to fault block. In this example, the

GUERRA and VICKSBURG Y EAST reservoirs are local names for separate reservoirs

within the Vicksburg. As such, GUERRA production (Figure 9) can easily be segregated

from the total Vicksburg production for mapping and analysis (Figure 10).


Figure 9: Bubble map of Guerra (Vicksburg) production in SE McAllen Ranch AOI, Hidalgo County, TX.


Figure 10: Bubble map of VKBG production in SE McAllen Ranch AOI, Hidalgo County, TX.


The Problem with Commingling Formation Code and Reservoir Name

Care must be taken to avoid importing production by Reservoir Name into a

project that already contains production by Formation Code, and vice versa. WellBase is

designed to handle dual completions and dual production streams, so it will interpret

the alternate production format of a single completion as a second production stream

for that well. In other words, wells with single completions will appear to have dual

production streams when production by Formation Code and production by Reservoir

Name are commingled.

For demonstration purposes, the IHS 298 data is again imported into the second

project example, but this time with the default setting of production by Formation Code.

In the case of the Guerra 47, VKBG, GUERRA, and VICKSBURG Y EAST are interpreted as

concurrent production streams from three separate zones. On the "Production" tabbed

page in WellBase, there are now two entries for each month, each with the same

production (Figure 11). Furthermore, cumulative production now stands at 11.5 BCFG

and 172 MBO, exactly twice what it should be!


Figure 11: WellBase view of Well ID 42215322890000 erroneously showing two streams for the first 9-

months production.

Summary and Conclusions

Appropriate selection of options when setting up a project can facilitate different

project objectives. For regional work, production by Formation Code provides the

benefit of IHS regionally aggregated stratigraphic nomenclature. For field studies,

production by Reservoir Name enables differentiation of multiple producing units within

a given stratigraphic zone. In this latter case, production data zones can be aliased to

aggregate reservoir names as necessary. In any case, commingling these two different

production data formats within a single project will corrupt the production table of the

project database.

Formation Code or Reservoir Name - LMKR · IHS provides production data by both Formation Code and...

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