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Microsoft Word - SR04Acquisition&ProcessingReport.docACQUISITION AND PROCESSING REPORT
February 2005
LIST OF CONTENTS
2 SUMMARY
4 DATA ACQUISITION
Fig. 2 Final Surveyed Line Locations
APPENDICES
I Survey Report by Dynamic Satellite Surveys Pty Ltd II Recording Production Statistics
III Guidelines for Environment and Cultural Heritage Protection and Pastoral Relations IV Data Processing Report by Velseis Processing Pty Ltd
V Tape List, Tape Header, VP/CDP Relationships, Processing Summary
1 INTRODUCTION
1.1 GENERAL
In July/August 2004 Santos Ltd, as operator of petroleum exploration and development in ATP 336P in the Surat Basin in Queensland, carried out the SR04 Seismic Survey of approximately 76 kilometres of conventional vibroseis reflection profiling in the Sunnybank area about 65 kilometres south-east of Roma.
The geophysical contractor was Terrex Seismic. Other contractors and sub-contractors were Dynamic Satellite surveys Pty Ltd, for horizontal and vertical surveying, Mr J Warby of Waggarie Exploration for permitting and ongoing liaison with landholders etc and Mr D Tickell for preparation of lines for vehicular access.
Santos Ltd also contracted Mr J Allen as field representative for the survey. Section 4, describing field operations, is largely drawn from his report.
Data processing was carried out by Velseis Processing Pty Ltd, in Brisbane.
Operations were managed and supervised by the Operations Geophysics team of Santos Ltd, Adelaide.
BB
B
G B
Legend
( G B ) ( B )B GC
GB G
G AG
G
B
B CB
GGG B
G G
B BC
PL 8
G GC
B E BG
BG G D C
( B G O K G C D ) ( E )W B B G
B B D B G
B
B
( G )G G
C G
G
EB PLB11 W B
( C )G BB
ATBP 336P Waldegrave
PSL 89 D
CEKOC E C
( E B W )G G
DB B OVB
G B
( B G )BS
W GWC
G OV B GG
( C G )PCL 64
B B B
B
B
G
BPL 27 B
( B )C G
( B )PLS56 S
S
G PL 71 G
( S )W T SS T C U
-27° 30'
( U B )B
UBU U C
B E E
( O )B T
S
149° 30'
Kilometres
1.2 LOCATION AND LOGISTICS
1.2.1 Location
The survey area is located in south-eastern Queensland, between latitudes 26o 51’ S and 27o 01’ S and longitudes 149o 10’ E and 145o 21’ E within the Parish of Tinowon, County of Waldegrave.
1.2.2 Terrain
The topography in the Sunnybank area is predominantly gently-undulating country cleared for cereal cropping, cattle grazing and native timber harvesting.
1.2.3 Access
The survey area is centred south-east of the intersection of the Yuleba-Surat and Roma-Condamine Roads, approximately 65 km south-eastward of Roma.
1.2.4 Accommodation
Line preparation and recording personnel were accommodated at the Roma Caravan Park and Club Hotel/Motel. The DSS surveyor was in rented premises at Surat. Daily travel time for those based in Roma averaged between 2 and 2.5 hours a day and from Surat, 1 hour.
Terrex cable, geophone and vehicle repair equipment, together with trailer- mounted workshops and a spare-parts trailer were set up at Aztex Pty Ltd yard in the Roma Industrial Area.
( S:\GEOPHYS\DenisonSuratBasins\2004\ATP336P\Reports\SR04Acquisition&ProcessingReport.doc- 10 )
1.3 TIMETABLE OF MAIN EVENTS
2 June 2004 : Notice of Intention to Commence Seismic Operations sent to Queensland Department of Minerals and Energy.
7 – 30 June 2004 : Permitting.
18 – 21 June 2004 : Cultural clearance.
18 July – 1 August 2004 : Line preparation/surveying.
28 July – 5 August 2004 : Recording.
13 August – 20 September 2004 : Data Processing.
2 SUMMARY
Principal contractor:
Terrex Seismic
Santos Field Rep :
Faywood (John Allen)
Data Processing :
3 vibrators, 2 sweeps per VP.
Weathering: No uphole programme required.
Environmental: Key Elements:
· Weave around significant trees
· Abide by all requirements of NBU environmental group
· No damage to fences, roads etc
· Avoid spread of noxious weeds
· Avoid and flag potential Aboriginal sites
· Disguise lines at road and track crossings
· Remove all markers after work completed
· Obey all fire restrictions and instructions as fire hazards exist
3 SURVEY SCOPE AND OBJECTIVES
The seven seismic lines acquired were designed to better define subsurface structure in the south-eastern portion of ATP 336P. All large conventional structures in the area have been drilled and this survey was intended to identify smaller structures and stratigraphic traps not previously defined.
Lines
Stations
Km
SR04-01
200-844
9.660
SR04-02
202-1329
16.905
SR04-03
200-626
6.390
SR04-04
200-754
8.310
SR04-05
200-813
9.195
SR04-06
200-782
8.730
SR04-07
200-1306
16.590
75.780
4.1 PERMITTING
Lines of the SR04 survey crossed portions of nine separate farming properties. All landholders including the Warroo Shire Council and the Department of Forests were visited by Mr J Warby on behalf of Santos Ltd before any work was undertaken, and “Notices of Intended Entry on Land” delivered, explained and signed.
With continuing liaison during field operations, relationships with landholders remained good, and no access problems arose. Compensation for crop damage etc was paid when justified. All landholders were revisited after completion of operations, and “Final Property Release” forms signed.
Two representatives of the Mandanjani people visited the proposed locations of seismic lines from 18 to 21 June and advised that no sites of cultural heritage were involved.
4.2 SURVEYING
Horizontal and vertical surveying of the seismic lines was carried out by Dynamic Satellite Surveys Pty Ltd, whose report is appended (Appendix I).
4.3 LINE PREPARATION
1 x Caterpillar D6D bulldozer with 12’ angle blade
1 x Caterpillar 12G grader with front bull blade Support vehicles
4.3.2 OPERATIONS
Most of the area covered by this survey has been cleared, seeded with Buffle grass and developed for cattle grazing. Selected areas on or marginal to the Balonne River floodplain have been developed for cereal crop cultivation. The eastern ends of lines 04 and 05 entered State Forest Reserves, as did the northern end of line 02. Cypress pine is the principal timber harvested in
these reserves. Other trees present include Wilga, Belah, Box and small amounts of Brigalow. Forestry roads provided limited access to lines in these woodlands classified as ‘Closed Forests’.
With the exception of the forest reserves the Sunnybank project had little impact on the environment. While earthmoving equipment was used in some way to prepare most lines, blade work was kept to an absolute minimum. The bulldozer walked lines across the seeded pastureland with blade work restricted to the removal of regrowth too extensive to detour. Sharp humps or washouts were levelled by the grader.
Cultivated areas were bypassed by the earthmoving equipment. Here, the surveyor marked the lines by driving through the crops prior to installing the station markers. Lines 01, 02, 04 and 07 passed through crops as detailed below:
Line Station Range
SR07 – 07 1241 - 1306
Trees had to be removed from lines extending into the woodlands. The bulldozer accomplished this with assistance from the grader using the bull- blade attached to its front end. Every effort was made to restrict clearing to a blade width (12’) but this was exceeded in a number of places where it was necessary to clear an area into which the fallen trees could be pushed.
The dense canopy severely restricted the use of the dozer mounted GPS navigational system. A large proportion of lines through the woodlands were cut by eye and therefore tended to be straight rather than weaved, as is the normal practice.
Two passes had to be made by the grader to clear sticks from these lines and to selectively spread the soil from the windrows back across the line leaving the sticks behind.
4.4 RECORDING
4.4.1 RECORDING EQUIPMENT
Complete ARAM 24, 24 bit telemetry recording system with the following ancillary equipment:
1
x
1
x
1
x
4
x
1
x
1
x
46
x
4.4.2 SOURCE EQUIPMENT
Four (4) Litton LRS315 40000 lb Peak Force 6x6 Paystar Truck-mounted Vibrators:
· Peak force is 40,600 lb per Vibe and
· Hold-Down weight is 42,400 lb per Vibe
· Five (5) Pelton Advance 2 Model 5 VCEs plus various spare boards
· One (1) Pelton Advance 2 Model 5 ESG for Recording Truck
· Four (4) Vibrators operating Online and One (1) on Standby
Vibrators are equipped with Force Control and Ground Force Phase Lock using M5I High performance accelerometers.
Electronics are capable of Trade-marked Varisweep
4.4.3 VEHICLES
1 x Isuzu 4x4 airconditioned recording truck
4 x LRS 315, 40,000 lb, Vibrators mounted on 6x6 International Paystar trucks
1 x Isuzu 4x4 Vibrator service truck
1 x Toyota 4x4 Series 100 station wagon
3 x Toyota 4x4 Series 79 cable trucks
1 x Toyota 4x4 Series 79 geophone truck
1 x Toyota 4x4 Series 79 line crew PC
1 x Toyota 4x4 line crew dual cab Hilux
2 x Toyota 4x4 Series 79 turbo utilities
Recording equipment including the dog box, truck carrier, ground electronics, cables and geophones were leased by Terrex from the Federal Government agency ANSIR (Australian National Seismic Imaging Resource).
4.4.4 RECORDING PARAMETERS
No. Channels : 240
Tape Format : SEGD, 8058IEEE Demultiplexed, 3490 Cartridge,
Noise edited correlated summed 3 sec record
Filters : Hi cut 123 Hz, 120 dB/Octave Lo cut 3 Hz, 12 dB/Octave
Sample Rate : 2 ms
Record Length : 9 sec (6 sec sweep, 3 sec listen)
RTC : Yes
Stack : Diversity stack plus burst edit Source Data
Vibrators : 3 Litton LRS315 40,000 lb peak force actuators on 6x6 International 5000 Paystar trucks
Electronics : Pelton Advance 2 Model 6
Sweep Frequency : 5-90 Hz
Sweep Length : 6 seconds
Sweep Function : Linear upsweep
No. Sweeps : 1
VP Interval : 15m
Vibrator Array : 3 in line, 15m. pad to pad centred between stations Drive Level : Maximum varied by amplitude control function Phase Locking Type : Ground Force using M51 accelerometers.
Amplitude Control : Peak to Peak
End Tapers (cosine) : 0.2s
Geophones : OYO Geospace 32CT, 10 Hz phones, 12 per string
Connection : Series Parallel (6x2)
Array : 12 in line, centred on station, 1.25m spacing
Multiplicity : 120 fold
4.4.5 PROCEDURE
Terrex used a line crew of seventeen to lay and move the geophones, cables and remote signal conditioners. A line boss and an assistant had responsibility for co- ordinating the crew and trouble-shooting the spread under the direction of the observer.
For the 15 metre group interval, geophones were laid along the line at intervals of approximately 1.25 metres such that there was also an interval of 1.25 metres between the last geophone of one group and the first geophone of the next. The line crew used four geophone and cable trucks, a trouble-shooter’s, and a line supervisor’s utility, all fitted with VHF radios to allow intercommunication, and contact with the observer, vibrator operators etc, when necessary.
The energy source was three vibrators in line, 15 metres apart, pad-to-pad, sweeping twice per vibrator point. Each sweep was a 5 to 90 Hz linear upsweep of 3 seconds duration.
Noise-edited, correlated and summed, three-second records were produced in SEGD format on 3490 E cartridges.
4.4.5 QUALITY CONTROL
Comprehensive instrument and vibrator tests were run each day, and during production the performance of all vibrators was constantly monitored via computer.
4.4.6 PRODUCTION
Production details are given in Appendix II. The average production rate was 2.06 km per recording hour.
4.5 ENVIRONMENTAL CONSIDERATIONS
As operator, Santos Ltd has, for a number of years, been committed to planning and conducting seismic operations in such a way that environmental disturbance is avoided or minimised, and affected areas can rehabilitate naturally in a reasonable time frame. For the environmentally similar Surat Basin, these objectives have most recently been set out and discussed in the publication “Code of Environmental Practice for Onshore Seismic Operations in the Denison Trough, Queensland” (Santos, 2000).
The commitment has normally included the distribution of copies of the above to all contractors’ personnel, and continual pressure by Santos Ltd field representatives on these personnel to conform to the principles and requirements of the Code.
Compliance with the Aboriginal Heritage Act has also been stressed and the strategy to ensure meticulous adherence to standard Santos procedures relating to Cultural Heritage Management and Environmental Sensitivity was reinforced by special training of key personnel, and daily meetings to re-iterate key issues and procedures.
With occasional, minor exceptions, the crews worked extremely well to complete the survey efficiently under the stringent environmental restrictions applied.
Other directives and guidelines issued to field personnel, relating to protection of the environment and cultural heritage, pastoral relations etc, are included in Appendix III.
5 DATA PROCESSING
5.1 GENERAL
Data processing was performed by Velseis in their centre in Brisbane.
Three seconds of data were recorded in the field, at a sample rate of 2 milliseconds. In processing, the data were reduced to a datum at 240 AHD. Surface elevations in the area of operation ranged from 233 metres to 283 metres above AHD.
Data processing effectively commenced on 13 August 2004 with the supply by Santos of static corrections to Velseis. Processing was completed on 20 September, when Santos received the final data.
5.2 PROCEDURE AND PARAMETERS
The processing stream and parameters are fully described in the processing contractor’s report, attached hereto as Appendix IV.
A summary, by Santos processing geophysicist P. Gatley, is submitted in Appendix V.
APPENDIX I
(Excluding Appendices)
Dynamic Satellite
Surveys 04048
for
July 2004
Santos Ltd / Terrex Seismic Pty Ltd 2004 Sunnybank 2D Seismic Survey
© Dynamic Satellite Surveys Pty Ltd 2004
This work is copyright. No part may be reproduced by any process without prior written permission from Dynamic Satellite Surveys Pty Ltd. Requests and inquiries concerning reproduction and rights should be addressed to:
The Director
Yeppoon QLD 4703
Facsimile: 07 4939 2867
Santos / Terrex Seismic Pty Ltd 2004 Sunnybank 2D Seismic Survey
1
INTRODUCTION
The following report covers the 2004 Sunnybank 2D Seismic Survey, performed by Dynamic Satellite Surveys Pty Ltd (DSS) whilst contracted to Terrex Seismic Pty Ltd for Santos Ltd.
The survey operation was situated 35km north east of Surat within the exploration lease ATP-336P, Queensland.
A total of thirty seven 2D seismic lines were surveyed totalling 75.78 kilometres at 15m station intervals. All lines were covered in 16 days giving an average of 4.7 kms per day.
The survey operations were completed between the 16th July and the 1st August 2004.
( Job #04048 July ) ( © Dynamic Satellite Surveys Pty Ltd 2004 ) ( 10 )
2
DSS personnel involved in the survey were as follows.
Tony Morcom - Bachelor of Geomatics (Surveying) - University of Melbourne.
Tim McCall - Bachelor of Applied Science (Surveying) QIT. Personnel and equipment logistics were supported by the DSS Yeppoon office. Survey operations were based at Surat.
2.2 Equipment
Description
Qty
Vehicles
3
1
Ver5.0.3
Field and Office Consumables
3
SURVEY REFERENCE SYSTEMS
3.1 Geodetic Datum
( Datum: GDA94(Geocentric Datum of Australia 1994) Spheroid: GRS80 Reference Frame: ITRF92 (International Terrestrial Reference Frame) Semi-Major Axis Length: 6 378 137.0 Inverse Flattening: 298.257222101 The Unit of Measure: International Metre )This project was based on the Geocentric Datum of Australia 1994 (GDA94) which is based on the Geodetic Reference System 1980 (GRS80) model defined by the following parameters:
3.2 Map Projection
( Projection: Universal Transverse Mercator (MGA Zone 55) Latitude of Origin: 0° Central Meridian (CM): 147° E Scale Factor at CM: 0.9996 False Easting: 500 000 False Northing: 10 000 000 The Unit of Measure: International Metre )Final rectangular coordinates were based on the Map Grid of Australia 1994 (MGA94). Parameters for this projection are as follows:
3.3 Height Datum
All elevations obtained relative to GDA94 have been reduced to the Australian Height Datum (AHD) using the AUSGEOID98 Geoid - Spheroid separation model to determine the geoid-ellipsoid separation (N) for the particular area.
GPS observations are made on the GDA94 datum. The height associated with this datum is an ellipsoidal height (h). The Australian Height Datum (AHD), the height datum associated with MGA94, is an orthometric height which is measured as the height above mean sea level, or the geoid (H).
The function that defines the relationship between the ellipsoid and orthometric heights is:
H = h - N
AHD = GDA94 - (Geoid / Ellipsoid Separation)
The value for the geoid/spheroid separation is interpolated from a national model called Ausgeoid98.
AUSGEOID98 is the third in a series of national geoid models produced for Australia by the Australian Surveying and Land Information Group (AUSLIG). The geoid-ellipsoid data is prepared for the Australian region from:
· EGM96 Global Geopotential Model;
· AUSLIG / AGSO GEODATA nine-second digital elevation model;
· Satellite altimeter - derived free air gravity anomalies offshore;
· Theories, techniques and software developed by Associate Professor Will Featherstone, Curtin University of Technology1.
AUSGEOID98 N values were interpolated using the GrafNet Version 6.02 software, distributed by Waypoint. Consulting Inc.
1 Johnston, G.M., Featherstone, W.E. (1998) AUSGEOID98: A New Gravimetric Model for Australia
4
SURVEY CONTROL
Survey Control was based on a mark installed on DSS Job# 03066, immediately to the south of the Santos prospect. This, in turn came from a Well permanent mark Norkam #1 BM2.
Check observations were made from each of the base stations during the real-time surveys and these miscloses and ties can also be seen in Appendix A - Survey Control, Miscloses and Ties.
5
MONUMENTATION
All lines were pegged at a 15 metre station interval. Wooden pegs were placed at every station and were numbered on both sides.
Several permanent markers were placed in the survey with the control stations being left in the ground to serve this purpose. Permanent markers consisted of a 1650mm steel star picket driven to give 1.2m above ground, and tagged with an aluminium plate stating the line number and relevant station number or control number details.
The permanent markers are listed at Appendix C - Permanent Markers.
6
METHOD OF SURVEY
6.1 Line Ranging
All lines were cleared by David Tickle Earthmoving contractors. The equipment supplied to perform the clearing was a Caterpillar D6D bulldozer and a Caterpillar 12G Grader.
The operators were experienced in preparation of seismic lines with regards to environmental issues, and easily learnt the GPS guidance techniques.
A Garmin 128 GPS receiver was mounted on the dozer, using a marine beacon to improve the accuracy of the position, to supply real time positions when cutting the seismic lines. Each lines coordinates (supplied by the client) were uploaded onto the GPS units and each line had a separate waypoint file.
The operator had few problems using the system but no time was lost due to GPS equipment down time during the seismic program.
Line pointing was required almost daily to confirm the correct path was being followed by the dozer operator. Some extra waypoints were needed to minimise clearing of scrub, confirmed by Santos representatives.
6.2 Surveying and Chaining
The lines were surveyed using DSS’ RT2 real-time kinematic surveying technique.
RT2 enables both position and elevation coordinates to be acquired in real-time and on the appropriate datum.
The survey method utilised phase data received from US Navy NAVSTAR Satellites to provide three-dimensional positioning. One receiver was set up as a base station at a known location while other receivers were used as remote rovers.
To obtain real-time capabilities, VHF telemetry is required between the base and the remote GPS receiver. Numerous remote receivers can be used at any given time with any base station.
NovAtel real-time kinematic methods can achieve accuracies of better than +/-0.05m in position and elevation, depending on base line length. The expected precision for locating pegged positions is better than 0.3 metres and is generally better than 0.2 metres.
Initialisation of the RT2 rover GPS usually takes as little as 1-2 minutes, although this is greatly dependant on satellite geometry, availability and base line length.
Through the thick trees, GPS heights were not accurate. There were sections on lines 2, 4, 5 and 6 that required manual chaining. The heights for these areas were measured using a Rapid Elevation Meter, an instrument designed by DSS using relative changes in pressure to measure the change in heights. All points measured are done so at least twice, with the standard deviation between measurements checked to ensure accurate results are obtained. The weather can play a large part in the accuracy of the instrument, and so the stable weather pattern throughout the REM survey resulted in accurate repeatability of measurements.
All lines were chained at 15 metre station intervals. A numbered wooden peg was placed at every station.
6.3 GPS Processing and Quality Control
When using RT2, all data is recorded internally in GRiD palmtop data loggers and downloaded to the office computer each evening.
Quality of the satellite data is monitored by careful examination of the various on-screen quality control statistics produced by the software.
These checks on data integrity are in the form of standard deviation (or sigma) values for Easting, Northing and Height and are generally better than 0.05 metres.
Any recording of positions when the standard deviation values are in excess of 0.1 m is highlighted to the surveyor at the time of recording, and the GPS may be re-initialised until a more accurate solution is calculated.
Any position which falls outside the required tolerances is flagged for further investigation and re-recording if necessary.
Numerous checks on pre-recorded marks were observed during each days survey. These observations confirm the integrity of the GPS base receiver and the placed markers.
The coordinates are then checked by determining point to point direction and distance. Profile plots are examined to identify any height anomalies.
7
DATA PRESENTATION
All line files were checked and finalised before the survey crew demobilised from the prospect.
All final data was in UTM grid coordinate format on the MGA94 datum on the GDA94 reference spheroid. All elevations were on the Australian Height Datum (AHD71).
Files produced were:
intersec.crd All new line intersections in .crd format
All files are backed up on digital disks in the Yeppoon office for future reference. No hard copy data was provided.
8
SAFETY
DSS personnel are aware of safety conditions concerning all exploration seismic surveys. The DSS “Quality Policy Statement” and “Health, Safety and Environment Policy” were adhered to at all times.
Each vehicle was fitted with a UHF radio, shovel, fire extinguisher, first-aid kit, vehicle recovery equipment, and weekly vehicle maintenance check lists.
UHF radio contact was always available between surveyors and with the line clearing contractors, once some work was done on the Survey radio. Regular contact was made throughout each day to ensure trouble free operations. Personnel were required to contact others before leaving the field.
Morning toolbox meetings highlighted any safety concerns which personnel encountered during the previous day and ensured everyone was informed about planned lines and progress. Some important points that were noted were:
· Always let others know if you are leaving the prospect.
· Ensure gates are left as found.
· Use caution driving along scrubby lines, there are some stumps just off line.
· Ensure UHF radios are on and on the correct channel.
· If you haven’t heard from others in the field for a time, check in.
9
All personnel were involved in Aboriginal Heritage Inductions before the commencement of survey operations.
Temporary gates or drop-down facilities were placed where gates could not be found near the lines, although large detours were the norm.
Seventeen kilometres of the total distance was through heavily timbered areas which slowed the line clearing dramatically. The trees were predominantly Cyprus-Pines and areas had been previously logged, leaving stumps behind that required avoiding or removing.
Due to the nature of GPS in trees, the flagged lines were not always exactly where the dozer GPS showed. Where this was the case, the dozer followed the flagging, as this was where the heritage survey had cleared.
The southern ends of line SR04-01 and the western end of line SR04-07, just over ten kilometres, were on previously cleared lines from the Origin 3D seismic survey (DSS Job# 03066).
A creek crossing on line SR04-07 was the only area that needed work by the earthmoving contractors. Gravel was placed there to ensure the crossing was not “chopped up” and rendered useless following the traversing by a number of vehicles.
Line trace diagrams and access maps were provided to the Terrex crew before the commencement of each area to aid in line traversing.
10
CONCLUSIONS AND RECOMMENDATIONS
The project generally ran smoothly for line clearing and survey. It is believed this is due in large part to the people involved being experienced at their relevant tasks.
The GPS equipment functioned well with no down time for line clearing and little for survey. The down time for survey was a problem with the base transmitter that required a resoldering job which was quickly resolved in the field.
Some problems were experienced with the heritage flagged lines. The coordinates did not exactly fit with the flagging which had the dozer operator concerned.
This was mainly due because flagging which was placed during the cultural heritage survey was not removed or relocated after additional bends were placed in certain lines. This meant that the dozer operator was sometimes having to guess between the GPS location and the incorrect flagging on the ground.
Only parts of the lines were driven/walked during the cultural heritage survey. This resulted in some bends being picked off the satellite image and some bends having to be entered in the field.
It would be recommended that if there was more time in the field during the initial heritage survey to cover the entire program, then all bends could be decided on the ground so that less dozer pointing would be needed. This would remove the need to place flagging in the field and would ensure that all parties are using the same, one set of coordinates.
The dozer quickly gained a lead on the survey due to the already cleared lines on the adjacent prospect. This, in turn, caused greater travel distances between the two when any problem was encountered.
There were no safety incidents on the project. Signed,
Tony Morcom
APPENDIX II
APPENDIX III
APPENDIX III
A. GENERAL
All crew members must strictly comply with the contents of the following publications:-
· Code of Environmental Practice, for Onshore Seismic Operations in the Denison Trough, Queensland (2000)
· Environmental Procedures for the Management of Aboriginal Heritage Sites (1998)
· Queensland Cultural Record Act
Disturbance to the terrain, vegetation (especially crops in arable areas) and infrastructure from all sections of the seismic survey is to be avoided or minimised. Recording and survey vehicles are to keep to prepared lines or tracks. Three point turns are required for turning. Lines intersecting roads or tracks should be concealed with dog-legs at the discretion of the line preparation personnel or Santos Field Representative. Public roads must have doglegs and verges reinstated upon completion. No disturbance or restriction to any water course. No removal of vegetation in or adjacent to creeks/water courses.
Strict adherence to the ”Code of Conduct for Seismic Crew Pastoral Relations, 1998” (below) is also mandatory. Restrictions imposed by Landholders must be observed. Gates are to be returned to their original state and fences must not be laid down unless prior permission by the landholder has been obtained. Broken wires are to be repaired and fences strained if necessary. Remove water only from locations agreed to by the landholder. If in doubt, refer to the Santos Liaison Officer (Jon Warby) or the Santos Field Representative (John Allen).
No vibrator point is allowed within 30m of any well, pipeline or installation. No personnel are to approach within 30m of a producing well without completion of a hot-work permit.
No survey metal pins are to be used. All points must be marked with wooden pegs which are to be removed after recording.
All vehicles must be thoroughly cleaned prior to, and immediately after, working in areas known to contain exotic/noxious weeds.
It is the responsibility of all crew personnel to report to the Santos Field Representative (SFR) any occurrences that do not meet the GAS criteria contained in the Code of Environmental Practice. Environmental Report Forms must be completed for any such occurrences that would score a “-1” or “-2”. The completion of such forms is the responsibility of the Santos Field Representative (SFR)
Cultural sites may be found in the area. Cultural Heritage Officers will have already visited the area and identified sensitive areas and sites prior to start of line preparation. These sites will be flagged and detours made around them. All sites identified will be reported on Environmental Report forms.
SFR will be responsible for completion of these forms.
Form G’s (Right of Entry Forms) must be carried by all personnel when on private land.
B. CODE OF PRACTICE FOR LINE PREPARATION/SURVEY CREW
(Bold print is specific for the SR04 project)
1. Restrict lines to one blade width.
2. Move as little earth and vegetation as possible.
3. Roll or walk lines only in silcrete and gibber plain areas - no blading.
4. Walk across claypans and consolidated flat open ground.
5. Avoid steep cuts and fills, which may cause erosion or landslide problems.
6. Cut sand dunes to the minimum depth required for safe access and operation.
7. Push sand to side of cut, not to bottom of dune.
8. Avoid or reduce to a minimum the formation of windrows.
9. Avoid destruction of isolated trees or stands of vegetation.
10. Avoid unnecessary blockage of creeks and channels.
11. Include erosion control features such as spur drains on sloping terrain.
12. Conceal lines from public roads or tracks by cutting 50 metres short on either side or placing a dog-leg to reduce line of sight in vegetated areas.
13. Offset crossings at drainage channels to avoid the removal of trees and vegetation.
14. Avoid sites of natural, historical, heritage, aboriginal and archaeological significance, known or discovered.
15. Stop and report all discoveries to supervisor.
16. All work is to be carried out with due regard to safety and consideration/ protection of the environment (including Cultural Heritage sites).
C. GUIDELINES FOR COMPLIANCE WITH ABORIGNAL HERITAGE ACT IN SA AND QUEENSLAND CULTURAL RECORD ACT 1987
There are three main points under the Aboriginal Heritage Act and Queensland Cultural Record Act 1987 relevant to field personnel or seismic crews.
1. No aboriginal site or object can be disturbed, interfered with or damaged.
2. All discoveries of aboriginal sites or objects must be reported to the Minister.
3. No aboriginal artefacts can be collected.
Each one of these points carries a $50,000 fine for the company or a $10,000 fine or 6 months imprisonment for the individual.
Santos Procedure for Aboriginal Site Avoidance
· A record of all known sites is kept in Adelaide office - this is updated regularly. All seismic program maps are checked against these maps before being sent to the field. Appropriate changes are made to the program if the proposed lines cross a known site.
Specific Guidelines for Compliance with Queensland Cultural Record Act 1987
Agreements are in place or being negotiated with relevant Aboriginal groups for Queensland Tenures. Although variations in the agreements exist, the following applies unless otherwise notified:
· The seismic crew may be required to attend an induction on the relevant group's culture and the relevant agreement.
· Line preparation will endeavour to be undertaken with representatives of the relevant Aboriginal Group.
· The Aboriginal representatives will mark off any sites that are on the programmed seismic lines and identify the most efficient detours around the sites.
· These sites must be avoided in subsequent activities.
· ERFs will be prepared by the seismic contractor and forwarded to Operations Geophysics in Adelaide.
D. SANTOS’ CULTURAL HERITAGE MANAGEMENT STRATEGY
Representatives (Cultural heritage officers) of the Mandanjani people programs will scout areas of native vegetation that are crossed by the seismic lines for cultural sites prior to line preparation.
Their role will be to provide cultural clearance by performing the following tasks. (Note that a DSS surveyor or Santos field representatives will guide them through the area.) Note that no inspections will be necessary in areas that have been cleared for cropping or grazing.
· Identify cultural heritage sites to be avoided.
· Peg and/or flag Cultural Heritage sites to ensure their integrity.
· Peg and/or flag areas of significant native vegetation (agreed between CHOs, Santos).
· Record all relevant details.
· Sign off the project as culturally cleared before moving to next project.
The following is a summary of the strategy in place to ensure adherence to standard Santos procedures relating to Cultural Heritage Management and Environmental Sensitivity. In summary, this will be achieved by:
- Daily toolbox meetings prior to work commencement to re-iterate key issues and procedures.
· Occasional presence on the crew of Adelaide or Brisbane environmental staff.
· Relevant landholders to be contacted for acceptance of cultural heritage officers undertaking clearance on their property.
Detailed steps in the above strategy are as follows:
1. The crew will be issued with appropriate documentation and handbooks, posters, etc for all personnel to access.
2. Supervision/overview of the line preparation operation and subsequent field operations will be maintained by Santos Field Representative, Santos Liaison Officer, DSS surveyor and NBU Environmental Department staff.
3. All sites of archaeological or cultural heritage significance identified during the course of the survey will be noted, pegged, flagged, avoided and reported as per Santos procedures.
- “Environmental Report Form - Seismic” to be completed for each site in our usual manner (Site Identification). Santos Field Representative will be responsible for production of these forms.
E. CODE OF CONDUCT FOR SEISMIC CREW PASTORAL RELATIONS
1. ALWAYS BEAR IN MIND YOU ARE ON SOMEONE ELSE’S PROPERTY. TREAT LANDHOLDERS AND THEIR FAMILIES WITH COURTESY. OBEY ALL LANDHOLDER SIGNS.
2. WHEN IN QUEENSLAND, ENSURE YOU CAN ALWAYS PRODUCE YOUR RIGHT OF ENTRY FORMS.
3. ALWAYS REVIEW THE “LANDHOLDER NOTIFICATION, PERMISSION AND CHECKLIST” FORM FOR THE PROPERTY YOU ARE WORKING ON TO ENSURE YOU ARE AWARE OF ANY RESTRICTIONS OR SPECIFIC REQUIREMENTS. ENSURE THIS FORM IS DISPLAYED ON THE CREW ENVIRONMENTAL NOTICE BOARD.
4. ALWAYS LEAVE GATES AS THEY ARE FOUND. (IF YOU COME ACROSS AN OPEN GATE REPORT IT TO THE LANDHOLDER VIA THE BIRD-DOG OR CREW MANAGEMENT.) LIKEWISE REPORT ANY DAMAGED GATES OR FENCES.
5. DO NOT LAY DOWN FENCES UNLESS YOU HAVE SPECIFIC PERMISSION FROM THE LANDHOLDER TO DO SO. IF SO ENSURE THEY ARE LAID DOWN AND PINNED TO MINIMISE DAMAGE TO THE WIRES.
6. REMOVE WATER ONLY FROM THOSE LOCATIONS AGREED TO BY THE LANDHOLDER.
7. NEVER SET UP CAMP CLOSER THAN ONE KM TO A STOCK WATERING POINT.
8. MINIMISE OR AVOID ALL DISTURBANCES TO STOCK.
9. STAY WITHIN SPEED LIMITS AT ALL TIMES AND, IN PARTICULAR, MINIMISE CREATION OF DUST CLOUDS ON STATION TRACKS NEAR HOMESTEADS. LOOK OUT FOR CHILDREN AND ANIMALS IN VICINITY OF HOMESTEADS.
10. MINIMISE OR AVOID CUTTING UP TRACKS OR RIVER CROSSINGS FOLLOWING WET WEATHER. IF UNAVOIDABLE, INFORM LANDHOLDER AND INSTIGATE PLANS TO RECTIFY DAMAGE.
11. DO NOT STRAY FROM WORK AREAS AND KEEP OFF-LINE ACTIVITY TO A MINIMUM (NO
SHORTCUTS!).
********************************************
NB. Non-adherence to any of the above rules will result in disciplinary action and may possibly lead to termination of employment or contract.
APPENDIX IV
TAPE LISTING FOR 2004 SUNNYBANK 2D SEISMIC SURVEY
Field Tapes
Archive Tapes
TAPE HEADER
C1 CLIENT: SANTOS LTD VOLUME: MIGRATED STACK - FILTERED SCALED C 2 SURVEY: SUNNYBANK PROCESSING 2004
C 3 AREA: ROMA
C 4 LINE: SR04-01 STATION/CDPS: 200/400-844/1688
C 5 STATION BYTES 17-20 CDPX BYTES 181-184 CDPY BYTES 185-188
C 6 PROCESSING: VELSEIS PROCESSING BRISBANE AUSTRALIA SEPTEMBER 2004 C 7 INPUT TO INTERNAL PROMAX FORMAT 2MS 3S
C 8 EDIT NOISY TRACES AND BAD RECORDS
C 9 GEOMETRY APPLICATION: ASSIGN SHOT AND RECEIVER COORDINATES C10 GAIN RECOVERY: TIME TO POWER CONSTANT 1.6
C11 CONVERSION TO MINIMUM PHASE
C12 DECONVOLUTION: SURFACE CONSISTENT SPIKING 100MS OPERATOR 0.1+ACU-PW C13 DESIGN: NEAR TRACE 7.5M 150-1500MS
C14 FAR TRACE 1800M 900-1800MS
C15 DECONVOLUTION: ZERO PHASE SPECTRAL WHITENING: 7-15-90-110 HZ C16 STATICS: REFRACTION STATICS FROM FIRST BREAKS ANALYSIS
C17 PROCESSING DATUM: 240M REPLACEMENT VELOCITY: 2000M/S C18 MODEL TIED TO CLIENT DATABASE
C19 MODEL SPLIT INTO SHORT AND LONG WAVE STATICS USING 1KM SMOOTHER C20 SHORT WAVELENGTH STATICS APPLIED TO FLOATING DATUM
C21 VELOCITY ANALYSES: SMOOTHED AREA FUNCTION C22 NMO
C23 RESIDUAL STATICS: AUTOMATIC SURFACE CONSISTENT MAX STATIC: 24MS C24 VELOCITY ANALYSES: 1000M INTERVAL
C25 CDP TRIM STATICS: THREE TRACE PILOT C26 DIP MOVEOUT
C27 VELOCITY ANALYSES: 500M INTERVAL C28 MUTE: FIRST BREAKS
C29 BALANCE: 500MS GATES OVERLAPPING BY 10+ACU- C30 CDP STACK
C31 STATICS: LONG WAVELENGTH ELEVATION STATICS APPLIED
C32 MIGRATION: STEEP DIP EXPLICIT FINITE DIFFERENCE WITH 100+ACU- VELOCITIES C33 STATICS SHIFT +65M- TO DATUM 305M VR 2000M/S
C34 C35
C38 C39
VP/CDP RELATIONSHIPS
735500M E
Station Interval : 15m
NOTE: '0' SYMBOL REPRESENTS A 3 WAY INTERSECTION AND/OR WELL TIE.
DATE :February 4, 2005 SCALE 1 : 50,000
( 150 ) ( 200 )COMBARNGO 1
( 114 )21CP858382
( 1033 )0 1 2 3 4 5
KILOMETRES
Mapsheet datum: "GDA94"
( 800 ) ( 600 ) ( 700 ) ( 793 ) ( 200 )328FTY1752
( 500 )
( SR 04-04 ) ( 250 ) ( 300 ) ( 400 ) ( 500 ) ( 560 ) ( 640 ) ( 720 ) ( 754 )328FTY1752
( SR 04-04 )
24WV348 5
( 600 ) ( 84 -W26 ) ( 600 ) ( 500 ) ( 400 ) ( 300 ) ( 200 ) ( 98 )3 6 2 4
SUNNYBANK 1
( 390 )84-W28
BOOKOOI 1
( 698 )
( 1100 )28WV932
( SR0 4-07 ) ( 200 ) ( 240 ) ( 320 ) ( 400 ) ( 480 ) ( 560 ) ( 640 ) ( 720 ) ( 800 ) ( 880 ) ( 960 ) ( 1040 ) ( 1120 ) ( 1200 ) ( 1280 ) ( 1306 )51WAL53657
( SR0 4-07 )
( S H85-417 )100
( 1226 )
60E5385
7010000M
149 10 00 E 149 15 00 E 149 20 00 E
7009500M
ATP 336P ROMA
( Distribution: Interstate Pipelines Pty Ltd (T. Gilby) Dept of Natural Resources & Mines (A. Lynam) Santos Ltd (Library) )Prepared by: Santos A.B.N. 89 010 829 017
March 2005
TABLE OF CONTENTS
SUMMARY 4 INTRODUCTION 5 GEOLOGY 5 Bowen Basin 5 Surat Basin 5 HYDROCARBON PLAYS 6 Source 6 Seal 6 Reservoir 6 Traps 6 OBJECTIVES 6 Southeast ATP336P Roma Area 7 SEISMIC DATA ACQUISITION & PROCESSING 8 INTERPRETATION 8 HORIZONS MAPPED 9 DATA ARCHIVE 10 CONCLUSION AND RECOMMENDATION 12 REFERENCES 12
FIGURES
Figure 2 ATP336 P and SR01 Seismic Grid
Figure 3 Stratigraphy
Figure 5 Seismic Section SR04-01
Figure 6 Seismic Section SR04-07
TABLES
Table 2 Bandanna Horizon Leads
Table 3 Basement Leads
Table 4 Data Archive
Enclosure 2 Seismic Section Line SR04-07 Migration
Enclosure 3 Top Bandanna Fm Seismic Time Map
Enclosure 4 Top Basement Seismic Time Map
Enclosure 5 Bandanna Fm to Basement Isochron
Enclosure 6 Net Tinowon Sandstone Map
APPENDICES
Appendix I SR04 Seismic Acquisition, Processing Report and Surveyor’s Report
Appendix II Recording Production Statistics
D:\QDEX\sunnybank\SR04 Sunnybank Final Report.doc
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Appendix III Guidelines for Environmental and Cultural Heritage Protection and Pastoral Relations
Appendix IV Data Processing Report
Appendix V Tape List, Tape Header, VP/CDP Relationships, Processing Summary
Appendix Figure 1 Location Map
Appendix Figure 2 Seismic Grid Location Map
Appendix Figure 3 Bowen/Surat Basins Stratigraphic Chart
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SUMMARY
The SR04 Seismic Survey was conducted in ATP336P Roma, from the 28th July to the 5th August 2005. The survey comprised seven lines of 2D acquisition totalling approximately 76 km and was completed with no HSE incidents.
The SR04 seismic survey was designed to address the south eastern portion of ATP336P, where no seismic coverage existed, and areas where the most prospective shows within the permit were recorded. In particular a north-south line was designed through the Sunnybank 6 well, which initially flowed OTS @ 630 bopd from the Rewan ‘C’ (top) sand. The SR04 data complemented the Roma Seismic Reprocessing Project (REFS), which was conducted concurrently and included 1400 line kilometres of varying vintage 2D seismic that encompassed the entire SR04 survey area.
Existing seismic within ATP336P Roma is dominated by mid 1980 vintage dynamite surveys. These show monoclinal structure dipping eastwards into the Taroom Trough from the Roma Shelf. The Permian Tinowon Sandstone and Triassic Rewan plays formed the focus of the SR04 survey. Trapping mechanisms within ATP336P are typically structural-stratigraphic in nature with pay zones often below existing seismic resolution. The majority of the SR04 survey was located in the southeast portion of the permit in an attempt to image the Tinowon sandstone and mature either anticlinal or stratigraphic traps.
The SR04 survey did not highlight any major structural or stratigraphic features or trapping mechanisms within ATP336P Roma. Within the survey limits, the monoclinal ramp structure dipping from west to east was again present. Variations in the isochron between the Bandanna Coal and basement indicate possible variations in depositional environment which in turn could indicate variations in reservoir. However this play is considered a very high risk at this time as the Sunnybank wells appear to have tested the isochron thick. Minor structural leads were identified. The imaging of the Sunnybank trap also failed to further improve the understanding of the stratigraphic trapping mechanism present due to the subseismic nature of reservoir sands.
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INTRODUCTION
The ATP 336 Roma is located in eastern Queensland and covers both the Permo-Triassic Bowen Basin and the Jurassic-Cretaceous Surat Basin (Figure 1). The ATP was awarded on October 1, 2003 and will be up for renewal in September 2007. Associated Petroleum Pty Ltd (Santos Ltd) holds an 85% (operator) stake whilst Interstate Pipelines Pty Ltd (Sunshine Gas Ltd) holds 15% of the permit. The ATP surrounds the Roma PL’s on the northern, eastern and southern side in two unconnected areas.
The SR04 seismic was recorded in the south east portion of the permit to try and further define the Rewan and Tinowon plays (Figure 2). In order to build up full fold small incursions were made into ATP631 (Origin Energy CSG Ltd operator), ATP647P (Starzap Pty Ltd operator), ATP 375 (Origin Energy CSG Ltd operator) and ATP 336P W (Associated Petroleum Pty Ltd operator).
Where necessary approval was sought for entry into the required permits prior to the beginning of the survey.
GEOLOGY
Bowen Basin
The Permian Triassic Bowen Basin formed under a Retro-arc Foreland Basin setting. Structurally the Basin experienced extension within the Early Permian followed by a period of thermal sag.
The mid-late Permian saw a period of compression often resulting in the inversion of normal faults.
The Bowen Basin depocentre is located to the east of the permit area, and is approximately 300m thick at the eastern edge of the permit, thinning to the west as the dips reduce over the Roma shelf. The Permian consists of interbedded shales, sands and coals (Figure 3) of fluvial to marine origin, and includes proven oil and gas reserves. The Permian also contains considerable fractions of volcanolithics, which in places degrades porosities.
Surat Basin
The Surat Basin is more gently structured than the Bowen, and displacements are generally not expressed as faults on seismic, but as flextures. The largest structuring occurs in the Hutton- Wallumbilla region and the Grafton Range field, located some 45km to the north west of the survey area. The Basin underwent a period of compression during the Early-Late Cretaceous which caused northern uplift and tilting to the southeast.
The Precipice Sandstone, the major gas producer on the Roma Shelf, unconformably overlies Permo-Triassic sediments and is the basal formation of the Surat Basin. Moving off the Roma shelf high sees the Triassic Snake Creek Mudstone acting as a regional seal. When present and where no faulting has provided vertical conduits, the mudstone causes hydrocarbons to be trapped within the Triassic and Permian sequences, with little hydrocarbon trapping within the overlying Jurassic sequences. This forms the geological case within the SR04 survey area.
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HYDROCARBON PLAYS
Source
Permian coals form the main source of the Roma hydrocarbons although minor production and shows within the Evergreen Fm are locally sourced. The migration path is from the centre of the Taroom trough westwards along bedding planes and faults.
Seal
The hydrocarbons are expected to be sealed by the Snake Creek Mudstone and by intra- formational seals within the Permian, the Triassic Rewan Fm and the Evergreen Fm.
Reservoir
The Precipice reservoir is expected to be water wet in the survey area, the primary objective being the Permian reservoirs, ie Lorelle Sst and Tinowon Sst and sands within the Rewan Fm. The Showgrounds Sst forms the secondary reservoir target.
Traps
Two trap types are envisaged:
1. Independent four way dip closure along west-east trending basement highs
1. A stratigraphic trap being formed by either the absence of reservoir along the crest of a plunging nose or as an embayment style pinchout.
OBJECTIVES
The objectives of the SR04 survey was to further define the Tinowon and Rewan plays within ATP336P. This was aimed to be achieved by firstly imaging any structural and stratigraphic trapping mechanisms that may be present within the south-eastern portion of the permit and secondly, through further defining the extent of existing traps.
Existing seismic within the permit is dominated by mid 1980 vintage dynamite surveys with some 1970’s lines present. Prior to the SR04 survey the south eastern portion of the permit was devoid of seismic coverage (Enclosure 1). The north-south trending Taroom Trough forms the eastern axis for Surat and Bowen Basins. It is here that the regional source, the Permian Blackwater Group is found. This currently exhibits both an oil and gas generating maturity towards the south east portion of the trough.
Migration pathways from source to trap are typically along permeable sandstone carrier beds with faults acting as conduits through both regional (Snake Creek Mudstone) and localised (Tinowon Siltstone) seals. Trapping mechanisms within the permit are typically structural-stratigraphic in nature with pay zones often below existing seismic resolution. Faulting styles within the permit are either normal, caused by Early Permian extension, reverse, caused by late Permian contraction or a combination of both in zones subjected to reactivation.
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Southeast ATP336P Roma Area
The Permian Tinowon Sandstone play is currently the most active play within Eastern Queensland. The Tinowon Formation was deposited in a fluvial deltaic environment with reservoir quality forming the critical risk for this play. All large conventional structures have been drilled, however, and remaining potential will be in smaller structures, not identified by the existing seismic grid, and stratigraphic traps. Recent drilling activity for the Tinowon has utilised air-nitrogen underbalanced techniques in an attempt to minimise reservoir damage. The Churchie Field (Santos 51%, Mosaic 49% (Operator)) along with Origin Energy’s Myall Creek Field are currently the main areas of activity for this play. Combined, the two fields have a 2P resource of over 70 Bcf. Flow rates greater than 5 MMscf/d have been recorded for both fields. Analysis of wells within the Tinowon fairway has indicated several paleovalleys which appear to control reservoir quality for Tinowon producing fields. Utilising gamma and sonic net sand cutoffs based on well data, a southwest-northeast trending net sand thickening (Enclosure 6) becomes apparent through the southeast corner of ATP336P, downdip of Appletree 1 and Tinowon 1. The majority of the SR04 survey was located here in an attempt to image the Tinowon sandstone and mature either anticlinal or stratigraphic traps.
The Rewan play is another emerging play in the area with similar reservoir quality issues. The Rewan is bound above and below by regional unconformity surfaces that negate the use of isopachs and other well based mapping techniques to determine depositional trends. Updip, Sunnybank 6 (2003) was a recent test of bypassed pay within the Rewan “C” sand where a fault bound stratigraphic trapping mechanism is present. On DST, the well flowed OTS @ 650 bopd with GTS @ 0.34 MMscf/d. This zone exhibited 1.7m of category 1 net pay, deposited as a fluvial channel sand. Early indications from a three hour production test recorded a stabilised oil rate of 630 bopd with 1.5 MMscf/d of gas. Well control to the north, west and east indicates a lack of this reservoir however minimal well control exists to the south. A north-south line through Sunnybank 6 was designed in an attempt to image a possible thickening of the reservoir to the south, and to provide a location for a possible appraisal well.
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SEISMIC DATA ACQUISITION & PROCESSING
Both Acquisition and processing are detailed in Appendix 1. Enclosure 2 is a sample of the processed seismic time section for SR04-07.
The seismic lines recorded and those re-processed within close proximity of the SR04 survey are shown within Table 1.
Survey
Line
Table1 INTERPRETATION
The data was interpreted and the raw data gridded on Geoframe 4.0.4.2 utilising a grid cell size of 250m. Sunnybank 6 was the most recent well within the interpretation area. This well was utilised to generate an initial synthetic (Figure 4) and to provide a starting point for the interpretation. Contouring and map production was done within the Petrosys dbmap package.
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HORIZONS MAPPED
(Enclosure 3)
The Top Bandanna Fm seismic horizon represents the coals at the top of the formation. The map is used to evaluate structuring at the reservoirs close to it, i.e. Basal Rewan Formation and Showgrounds Sandstone. Moving from west to east sees a rapid change from the Roma Shelf to the northwest into the monoclinal ramp structure that extends into the Taroom trough. This change is also seen in Figure 6, along line SR04-07. Moving north to south along SR04-01 (Figure 5) sees a slight shallowing of the Bandanna Coal to basement section.
Three structural leads exist at this level, outlined in Table 2. The leads consist of structural noses, downthrown fault blocks and small closures. The basement faulting which creates an isolated fault block within the Sunnybank area is less visible at the Bandanna TWT level.
Bandanna Horizon Leads
Closure sq km
(Enclosure 4)
The Basement time map is used to evaluate structuring of the Permian reservoirs. Again the TWT map indicates a monoclinal structure dipping eastward. Structural leads at this level consist of noses, downthrown fault blocks and small closures. These leads and their respective sizes are listed in Table 3. The Sunnybank area is part of an isolated fault block with the possibility of the two faults converging to the north. Although the trapping for this area is within sands of the Triassic Rewan Formation, this downthrown basement fault block may have formed a focal point for sedimentation at later times.
Basement Leads
(Enclosure 5)
The Bandanna Isochron is relevant for any intra-Permian stratigraphic traps. It is assumed that the Permian sands may be thicker where the sedimentary interval thickens. Four noticeable features occur within and nearby to the SR004 survey area. A north northwest to south south east trending isochron thick extends along some of the length of SR04-01. This follows the approximate orientation of the main western fault in the area and falls on the down thrown side of this fault where increased sedimentation would be expected. Another anomaly trending approximately
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northwest to southeast within the vicinity of the Sunnybank wells also occurs. Two southwest to northeast trending isochron thicks begin within the vicinity of line 84-w22.
These thicker packages may represent fluvial paths within the Permian Formations. Moving off the Roma Shelf high into the Taroom Trough sees the unconformity surface between the Triassic and Permian units become more conformable.
DATA ARCHIVE
The Geoframe Project “roma_client” which contains the SR04 data, has been archived on Exabyte tape. This report, figures and enclosures as well as gridded and contoured data, faults and polygons have also been archived on that tape. Table 4 contains the locations of all files within Santos’ unix system.
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CONCLUSION AND RECOMMENDATION
The SR04 seismic survey was conducted in a safe, environmentally responsible and timely manner.
The seismic mapping indicates that there are three and eight structural leads present at the Rewan and Tinowon reservoir levels respectively. The survey however has not increased the understanding of the trapping mechanisms within the Sunnybank area due to the subseismic nature of the 1.7m category 1 net pay present here. The area north of the SR04 seismic survey still contains large areas that contain either no seismic data or only sparse 1972 vintage regional lines. Any future seismic survey in that area should be targeted where reservoir quality is likely to be more favourable than at the Sunnybank area.
Two Bandanna Coal to basement isochron thickenings occur within the vicinity of the Sunnybank area trending north northwest to south southeast and northwest to southeast. These may indicate Permian and Triassic fluvial paths. However the seismic resolution is of marginal quality for detailed stratigraphic work, due to the high amplitude coals present.
References
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