Interpretation Report for Seismic Survey ‘Surprise 3D, 2012’ · 2019. 3. 5. · Seismic interpretation ... Table 2: Seismic processing steps for stages 1 to 3 – Time, depth

Interpretation Report

for

Seismic Survey ‘Surprise 3D, 2012’ Time domain processed, October 2012

Depth domain processed, February 2013 Specialised depth domain processed, February 2014

By

Central Petroleum Ltd

Lvl 32, 400 George Street

Brisbane, QLD 4000

February 2015

Interpretation Report for Seismic Survey ‘Surprise 3D, 2012’ by Central Petroleum Ltd __________________________________________________________________________________

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Table of Contents 1. Introduction ................................................................................................................................ 3 2. Seismic acquisition ...................................................................................................................... 4 3. Seismic processing ...................................................................................................................... 4

3.1 First-stage processing (time domain)........................................................................................ 4 3.2 Second-stage processing (time & depth domains) – Isotropic tomographic inversion ............ 5 3.3 Third-stage processing (time & depth domains) – Anisotropic tomographic inversion ........... 5

4. Objectives.................................................................................................................................... 8 5. Seismic interpretation ................................................................................................................. 9

5.1 Horizons and surfaces ......................................................................................................... 9 5.2 Synthetic seismogram ....................................................................................................... 10 5.3 Depth conversion .............................................................................................................. 10

6. Results ....................................................................................................................................... 11 7. Conclusions ............................................................................................................................... 11

Table of Figures

Figure 1: Location map – Seismic survey ‘Surprise 3D, 2012’. ........................................................................... 3 Figure 2: Migrated stack (TOMO-10 update, 2nd processing stage) – Interval velocities overlain. .................... 6 Figure 3: Composite seismic section through 3D cube – Synthetic seismogram of Surprise-1R. ....................... 8 Figure 4: Composite synthetic seismogram, logs and seismic panel – Surprise-1R. ........................................ 10 Figure 5: ‘Seismic 3D, 2012’ processed cubes. (a) Time, (b) Depth, (c) Interval velocity and, (d) Time slice. ... 12 Figure 6: Depth structure (differentially processed) – Lower Stairway Sandstone: (a) isotropic TOMO-10 update (stage 2), (b) isotropic TOMO-7 update (stage 3), (c) anisotropic TOMO-7 update (stage 3) and, (d) residual (isotropic TOMO-10 minus ISOTROPIC TOMO-7 update). ................................................................. 13 Figure 7: Seismic inline sections, (a) 1120, (b) 1170 (Surprise-1R), (c) 1220 and, (d) 1320. ............................. 17 Figure 8: Seismic crossline sections, (a) 5090, (b) 5140 (Surprise-1R), (c) 5190 and, (d) 5240. ........................ 21 Figure 9: TWT Structure (msec-SS) – Mereenie Sandstone. ............................................................................ 22 Figure 10: TWT structure (msec-SS) – Carmichael Sandstone (unconformity). ............................................... 23 Figure 11: TWT structure (msec-SS) – Stokes Siltstone. .................................................................................. 24 Figure 12: TWT structure (msec-SS) – Lower Stairway Sandstone. ................................................................. 25 Figure 13: TWT structure (msec-SS) – Pacoota Sandstone. ............................................................................. 26 Figure 14: TWT structure (msec-SS) – Goyder Formation (unconformity). ..................................................... 27 Figure 15: TWT structure (msec-SS) – Base Giles Creek Dolostone (unconformity). ....................................... 28 Figure 16: Depth structure (m-SS) – Mereenie Sandstone. ............................................................................. 29 Figure 17: Depth structure (m-SS) – Carmichael Sandstone (unconformity). .................................................. 30 Figure 18: Depth structure (m-SS) – Stokes Siltstone. .................................................................................... 31 Figure 19: Depth structure (m-SS) – Lower Stairway Sandstone. .................................................................... 32 Figure 20: Depth structure (m-SS) – Pacoota Sandstone. ............................................................................... 33 Figure 21: Depth structure (m-SS) – Goyder Formation (unconformity). ........................................................ 34 Figure 22: Depth structure (m-SS) – Base Giles Creek Dolostone (unconformity). .......................................... 35

Table of Tables Table 1: Acquisition parameters for seismic survey ‘Surprise 3D, 2012’. .......................................................... 4 Table 2: Seismic processing steps for stages 1 to 3 – Time, depth and interval velocity cube outputs. ............. 7 Table 3: Seismic horizons. ................................................................................................................................ 9


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1. Introduction The survey area for seismic survey ‘Surprise 3D, 2012’ is located in the western half of EP-115, the latter being located four hours’ drive west of Alice Springs (Fig. 1). The seismic coverage in the Surprise area is approximately 1 line per 4 km2. A seismic 3D was acquired as a result of the oil discovery by Central Petroleum Ltd – Surprise-1 was re-entered (Surprise-1R) and side-tracked (Surprise-1R HST1, re-entry horizontal sidetrack-1). The 3D grid straddles the subsurface oil pool. Terrex Seismic acquired the seismic data, Terrex Spatial carried out the surveying, contractors pre-processed the field data and DownUnder GeoSolutions processed the data.

The pre-approvals included line clearance, rehabilitation plans as well as a eco-survey to report on the seismic survey’s potential impact on flora and fauna. Other sensitivities were pre-empted, in particular, an exclusion zone bounding the south-eastern edge of the seismic grid area. The acquisition was carried out flawlessly even while the Surprise oil well was being flow-tested. Ground receiver cables were protected adequately against minor ground traffic during flow-test operations, no traffic noise was detected, and wind noise was at a minimum.

Both time and depth domain as well as interval velocity cubes were output from processing stages two and three, only a time cube from stage one. The primary reservoir objective (Lower Stairway Sandstone) was interpreted on all cubes whereas all other horizons were interpreted in processing stage-2. This report describes the seismic interpretation and ensuing outcomes – inline and crossline sections, examples of a seismic time slice as well as relevant TWT and depth maps are shown. The interpretation is tied to Surprise-1R where logs were obtained prior to drilling the side-track well ‘Surprise-1R HST1’. Only the Surprise-1R well will be referred to in this interpretation report.

Figure 1: Location map – Seismic survey ‘Surprise 3D, 2012’. Exclusion zone: area where approval is required in order to gain access to aboriginal-owned land.


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2. Seismic acquisition The ‘Surprise 3D, 2012’ seismic survey was the first ever 3D acquired in the Northern Territory – acquisition spanned the period June – July 2012. The size of the survey area was extended in order to adequately image a deeper Neoproterozoic salt target in addition to the overlying Ordovician oil-bearing Lower Stairway and Pacoota Sandstone reservoir objectives.

The survey used cabled technology, and source and receiver line parameters are tabulated (Table 1). Vibrator sweep tests were conducted to optimise source energy input – final key acquisition parameters included 1 sweep per VP, a sweep length of 12 sec, a sweep range of 6–72 Hz, a 300 ms start taper and a drive level of 75%. Pre-processing was carried out during the first two days of acquisition – sweep tests, raw shots, frequency spectra and brute stacks were relayed to head office. Detailed information relating to the acquisition can be found in the field operation’s report ‘Surprise 3D seismic survey’ written by Terrex Seismic as well as the surveying report written by Terrex Spatial – both reports were submitted to the Government.

Table 1: Acquisition parameters for seismic survey ‘Surprise 3D, 2012’. Data recorded by Terrex Seismic Date recorded 30/6/2012 to 12/7/2012 Total square km 81.9

Source parameters Seismic source Vibroseis, 3 x Hemi 50, 3 inline, 15 m pad-to-pad Sweep length 12 sec Sweep frequency 6–72 Hz, linear sweep Sweeps per VP 1 VP interval 50 m along 350 m spaced lines trending at 119.3° E-of-N, lines orthogonal

to receiver lines. Total no of source point locations is 4911, equating to 57 sources/km2, max inline offset is 3,850 m.

Receiver parameters Group interval 50 m along 350 m spaced lines trending at 209.3° E-of-N, lines orthogonal

to source lines. Total no of receiver point locations is 4858, equating to 57 receivers/km2, max crossline offset is 2,800 m.

No channels 2464 live channels, 16 lines with 154 live channels on each line Record length 6 sec Receiver array 12 over 50 m, centred on peg, 4.16 m spacing Multiplicity 88, bin size 25 X 25 m

3. Seismic processing

3.1 First-stage processing (time domain) The first-stage processing output is a time domain 3D cube; processing was conducted between July and October 2012. The cube includes inlines 5000–5309, crosslines 1000–1448 with a TWT range of 0–6500 msec. The survey datum used is GDA-94 and the UTM zone is 53. Test and final stacks were produced using a bandpass filter of 5–12–65–70 Hz. The key processing steps from the EBCDIC header for the first-stage processing are outlined in table 2 (step 1); included are:

• Four passes of velocity picking, starting off at a 2 X 2 km spacing; and, • Use of refraction statics (no upholes were acquired)


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3.2 Second-stage processing (time & depth domains) – Isotropic tomographic inversion The second stage processing outputs both time and depth domain cubes, processed using isotropic tomographic inversion – processing was conducted between November 2012 and February 2013. The objective of the depth image processing was to obtain a better velocity model and tie to the well data. Also, this stage was deemed necessary as lateral velocity variations are expected in a basin that has been shortened and uplifted – unconformities and complex contacts abound. The second stage processing involved 10 isotropic tomographic inversion updates – these are abbreviated in this report, for example TOMO-10. An example of the resultant depth migrated stack can be seen in figure 2 with interval velocities overlain (colour fill). Note the velocity inversion present in the Mereenie Sandstone (blue colour in mid-section). The final processing sequence is summed up below – key differences from the processing of the stage-1 time-domain cube can be seen in Table 2 (step 2).

• Ten iterations of tomographic velocity analysis were applied to the data at a 100 meter interval – the stage-1 processed migration velocities served as an initial input. Tomography update-1 to 3 were densely picked up shallow and sparse down deep – the sonic log for Surprise-1R was introduced in the TOMO-3 update. Tomography updates 4 and 5 were run to top salt (ie. Base Giles Creek Dolostone). Residual moveouts reduced greatly as illustrated on CDP gathers for the TOMO-6 to -10 updates. Well markers were introduced in the TOMO-6 update in order to anchor velocities at the Parke Siltstone and Mereenie Sandstone levels; thereby, resulting in a bulk shift when reducing the overburden velocities accordingly.

• A Kirchhoff pre-stack depth migration was used; the offset bin range is 100–4700 m (100 m increment), aperture 3000 m, depth step 3 m, velocity grid 200 X 200 m with a 3D input data grid of 25 X 25 m.

• A residual moveout correction (RMO) was automatically calculated every 100 m, manually picked every 500 m and applied to flatten the CDP gathers. The RMO attempts to correct for non-hyperbolic moveout as well as short wavelength spatial velocity changes due to anisotropic changes in the geology. The RMO corrections are minimized greatly by the TOMO-10 update.

• An outer trace mute was applied to the data before stacking to supress direct arrivals, refraction energy and NMO stretch.

• Angle stacks were produced at the following offset ranges: 0–35, 5–15, 15–25, 25–35 and 35–45 degrees.

• The data was stacked according to an inversely normalisation function that is based on fold of coverage.

• A final datum shift of 500 ms was applied to correct from the processing datum to MSL.

3.3 Third-stage processing (time & depth domains) – Anisotropic tomographic inversion The third processing stage outputs both time and depth domain cubes, processed using anisotropic tomographic inversion – processing was conducted between December 2013 and February 2014. The third seismic processing stage was deemed necessary as a result of a local velocity anomaly that was distorting the integrity of the structure within the closure of the oil accumulation.

• The isotropic pre-stack depth migrated TOMO-6 update was used as input to the anisotropic tomographic inversion. Two methods were used to correct for the local velocity anomaly:


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Method 1: The interval velocity was scaled against key horizons using a velocity field that was 6% lower.

Method 2: The TOMO-6 velocities were scaled accordingly using a synthetic delta function that was calculated using a fit to the blocked sonic log in Surprise-1R – the scaling was carried out in the time domain. The anisotropic velocity function was scaled by dividing the isotropic velocity by 1 plus the synthetic delta function – the scaling is only accurate between a TWT of 300 and 900 ms where the sonic log is available.

• The two pre-stack depth migrated stacks were then be compared in both the time and depth domains (Table 3, 3rd stage, methods 1 & 2).

• De-noise testing was also carried out using: (a) First-pass time frequency denoise (TFD1), (b) linear random demultiple, (3) parabolic radon demultiple, (4) second pass time frequency denoise and, (5) third pass time frequency denoise.

Note that RMO and repicking of velocities in stage three were not carried out following the TOMO-7 update as was done in the second processing stage – time and cost constraints being the dominant factor to the processing contractor.

Figure 2: Migrated stack (TOMO-10 update, 2nd processing stage) – Interval velocities overlain.


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Table 2: Seismic processing steps for stages 1 to 3 – Time, depth and interval velocity cube outputs. Note: sourced from the EBCDIC header. Text in red represents differences between time and depth flows. Processing steps C11–C18 represent the base processing flow – only steps C19–C22 differ across stages 1–3.

Step Seismic processing steps Stage C11 Reformat from SEGY to internal format, designature, merge geometry database

1st to 3rd

C12 Spherical divergence correction, elevation statics C13 Ground-roll removal in shot domain, monochromatic frequency filter C14 Despike in CDP and receiver domains, DUG LNR (linear noise removal algorithm that

uses inversion to reduce operator smearing, carried out in shot, receiver and CDP domains)

C15 First pass surface consistent scaling, surface consistent deconvolution (160 ms op.) C16 Second pass surface consistent scaling, despike in CDP domain C17 Despike in receiver domain, radial transform in shot domain C18 Refraction statics correction, residual statics correction **** *********************************************************************** ********* C19 Trim statics correction, DUGREG, pre-stack migration

1st C20 Migration velocity NMO correction, mute, stack, spectral whitening C21 Time variant filter, bulk shift down 500 msec, SRD, output SEGY Final migrated stack in time **** *********************************************************************** ********* C19 Trim statics correction, DUGREG, TOMO-10 update

2nd

C20 Tomo-10 velocity extrapolation, pre-stack depth migration C21 Conversion to time, RMO, new mute, stack, bulk shift -500 msec C22 Correction to SRD, output SEGY TOMO-10 extrapolated migrated RMO stack in time C19 Trim statics correction, DUGREG, TOMO-10 update C20 Pre-stack depth migration, RMO, mute, stack C22 Output SEGY TOMO-10 migrated stack in depth **** *********************************************************************** ********* C19 Trim statics correction, DUREG, stack sum, TFDN, randon demultiple

3rd method 1

C20 Scale down 6% up shallow for TOMO-6 velocity update, TOMO-7 velocity update C21 Isotropic pre-stack depth migration, conversion to time, mute, stack, C22 Bulk shift -500 msec, correction to SRD, output SEGY TOMO-7 isotropic pre-stack depth migrated stack in time C19 Trim statics correction, DUREG, stack sum, TFDN, randon demultiple C20 Scale down 6% up shallow during TOMO-6 velocity update, TOMO-7 velocity update C21 Isotropic pre-stack depth migration, conversion to time, mute, stack, C22 Conversion to depth, output SEGY TOMO-7 isotropic pre-stack depth migrated stack in depth **** *********************************************************************** ********* C19 Trim statics correction, DUREG, stack sum, TFDN, randon demultiple

3rd method 2

C20 Scale down 6% up shallow during TOMO-6 velocity update, TOMO-7 velocity update C21 Anisotropy model building, anisotropic pre-stack depth migration C22 Conversion to time, mute, stack, bulk shift -500 msec, correction to SRD, output SEGY TOMO-7 anisotropic pre-stack depth migrated stack in time C19 Trim statics correction, DUREG, stack sum, TFDN, randon demultiple C20 Scale down 6% up shallow during TOMO-6 velocity update, TOMO-7 velocity update C21 Anisotropy model building, anisotropic pre-stack depth migration C22 Conversion to time, mute, stack, conversion to depth, output SEGY TOMO-7 anisotropic pre-stack depth migrated stack in time


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4. Objectives The interpretation focussed on horizons lying above the unconformity that is associated with the Petermann Orogeny (ie. Base Giles Creek Dolostone, Table 3, Fig. 3). Horizons include the Lower Stairway Sandstone (ie. primary reservoir objective), Stokes Siltstone (ie. regional seal), Horn Valley Siltstone (ie. source-rock interval) and Pacoota Sandstone (ie. secondary reservoir objective). A second Surprise well is under consideration, with the possibility to test deeper objectives if the location is in the west end of the field. Seismic reflector packages present below the Base Giles Creek Dolostone unconformity are present, however imaging is compromised by salt diapirism such that the configuration of trap(s) is less certain. Perhaps reprocessing focused on improving the deep section might assist.

The structure bearing the oil accumulation at the Surprise Field was known, prior to acquisition of the seismic 3D data, to be bifurcated by NNW-SSE trending faults which sole out at the Stokes Siltstone/Carmichael Unconformity. Thus the possibility was recognised of compartmentalizing the accumulation, and the field having a stratigraphic component which might affect reserve estimates. The underlying salt diapirism and associated salt-cored anticline was interpreted to be responsible for the shallower complex fault sets seen at the level of the reservoir and seal, some faults probably undetectable on 2D seismic data. However with the benefit of 3D seismic data the faults were re-interpreted as minor and the azimuth for the principal NNW–SSE-trending faults adjusted.

Interpretation of the time-domain (phase 1) seismic 3D cube, isotropic TOMO-10 (phase 2) and final isotropic/anisotropic TOMO-7 (phase 3) cubes improved ties to the well, and ultimately provided more confidence in the mapped structure.

Figure 3: Composite seismic section through 3D cube – Synthetic seismogram of Surprise-1R. Vertical scale: msec-SS. The composite section was extracted from the TOMO-10 processed cube (2nd stage).


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5. Seismic interpretation

5.1 Horizons and surfaces Horizons interpreted and the rationale for interpreting them are tabulated (Table 3). Both inline and crossline sections as well as TWT and depth maps are included in figures 7–22.

Four regional unconformities are observed in the basin (ie. Areyonga, Base Giles Creek Dolostone, Goyder, Carmichael). The unconformities reflect important tectonic basin phases and have been taken as key markers during the interpretation phase – these are described briefly, as follows.

• The Areyonga Unconformity reflects the Neoproterozoic Areyonga Movement and is regional in extent – it is not well imaged on the 3D seismic data. Formations subcropping the unconformity include the Gillen Member, Loves Creek Member and Johnnys Creek Beds.

• The Base Giles Creek Unconformity reflects the Petermann Orogeny, the latter responsible for causing differentiation of the Officer and Amadeus basins. Truncational erosion is observed regionally (eg. Fig. 7) – formations subcropping this unconformity are numerous and difficult to identify locally due to limited well control.

• The Goyder Unconformity reflects the Delamarian Orogeny. The Goyder Formation has clastics present above the unconformity and a carbonate present below. As such, the unconformity is generally associated with a high amplitude reflector where the carbonate is present.

• The Carmichael Unconformity reflects the Rodingan Movement, the latter equivalent to the first movement associated with the Alice Springs Orogeny.

All other horizons interpreted between the regional unconformities are key markers and/or reservoir–seal units (see Table 3).

Table 3: Seismic horizons. Formation top

/Seismic horizon Rationale for interpretation TWT/depth

maps Mereenie Sst Water aquifer, important to interpret when juxtaposed against

potential petroleum-bearing reservoirs Figs 9/16

Carmichael Sst (Unc.)

Top coincident with the Rodingan Movement (basal Alice Springs Orogeny) Figs 10/17

Stokes Slst Top of regional seal and marine sequence Figs 11/18 Stairway Sst Top of upper clastic/carbonate sequence, oil/gas shows present

within No maps

Lower Stairway Sst

Top of oil-bearing reservoir (primary objective at Surprise-1R) Figs 12/19

Horn Valley Slst Top of source rock interval (primary source rock at Surprise-1R) No maps Pacoota Sst Top of potential reservoir (primary objective at Mereenie Field),

secondary objective on the Surprise structure Figs 13/20

Goyder Fm (Unc.) Top coincident with the Delamarian Orogeny, transition from carbonate-to-clastic lithology in places Figs 14/21

Tempe Fm Top of potential secondary source rock interval No maps Base Giles Creek Dolostone (Unc.)

Top coincident with the Petermann Orogeny, basin-wide unconformity & megasequence boundary Figs 15/22


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5.2 Synthetic seismogram A synthetic seismogram was produced for Surprise-1R (Fig. 4) – a composite section shows the tie to a seismic panel extracted at the well location (Fig. 3), key logs are also shown. Note the velocity inversion within the Mereenie Sandstone.

Figure 4: Composite synthetic seismogram, logs and seismic panel – Surprise-1R. Abbreviations: AI – acoustic impedance; GR – gamma ray; DT – sonic; RC – reflection coefficient, RHOZ – density. Logging commenced in the Parke Siltstone. A 25 Hz Ricker wavelet was extrapolated from the seismic data at the well location to produce the synthetic seismogram – the seismic panel is taken at the well location.

5.3 Depth conversion Depth conversion of the Surprise 3D time cube was carried out through inversion of the cube with velocity constraints originating from Surprise-1R’s sonic log and associated checkshots. Depth cubes were produced, as previously discussed (Table 2; ie. isotropic TOMO-10 (stage 2) and TOMO-7 (stage 3) inversions as well as the anisotropic TOMO-7 (stage 3) inversion). An interval velocity cube is output for each of the inversions – a time, depth and interval velocity-cube example is shown in Figures 5a–c.


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6. Results Key outcomes from the interpretation of the Surprise 3D grid are as follows.

• The structure at the Surprise location is a salt-cored anticline that becomes more arcuate with depth. Several faults tip-out at the Stokes Siltstone/Carmichael Unconformity (Figs 7–22), their origin linked to salt diapirism. Furthermore, it is probable that other minor and sub-seismic faults are also present. It follows that some degree of fault compartmentalization is anticipated, the degree of which will remain unknown until further wells are drilled. The interpretation has also demonstrated that across-fault seals can be effective in holding a hydrocarbon column since the oil accumulation at the Surprise structure is a 3-way dip closure (Fig. 5d).

• The Surprise structure has a relatively small areal closure; thereby, limiting the size of potential oil pools present at the stratigraphic level of the Lower Stairway Sandstone (ie. LCC at -2016 mSS, Fig. 5d). Also, the prospectivity of pre-Pacoota Sandstone stratigraphic intervals remains undrilled and unknown. However, outcrop geology suggests that the Cleland Sandstone should be present; also, the Tempe Formation is interpreted (Fig. 3) although it’s closest well intersection is located 80 km to the east at Mt Winter-1.

• The top Lower Stairway Sandstone was interpreted on the time and depth cubes for all three stages of processing (Figs 6a–c). The depth maps, when compared, show subtle shifts in the crest of the structure mapped with the isotropic TOMO-7 depth cube being near-coincident with that on the time cube, more in-line with what would be expected – a residual map shows up the difference (Fig. 6d). Any small lateral shift of the other horizons is deemed too subtle to change the outcome of the interpretation, the latter made off the TOMO-10 cube.

7. Conclusions The following points are inferred from the results.

• The oil accumulation at Surprise-1R is pooled in a three-way dip fault-bound closure; thereby, indicating that across-fault seals are capable of holding back hydrocarbons. Thus, other accumulations could be present in fault-bound traps even though the basin has been severely shortened and thrust faults abound – fault-bound traps need to be included in the prospect portfolio and individual prospects considered on their own merit.

• The closure is best represented by the -2016 m contour. A small graben separates the western oil accumulation from the eastern closure where oil may be pooled.

• A deeper play directly below the Base Giles Creek Dolostone unconformity may exist but the interpretation of any potential trap is not forth-coming within the 3D area.

Seismic interpretation report – Surprise 3D, 2012 by Central Petroleum Ltd _______________________________________________________________________________________________________________________________

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Figure 5: ‘Seismic 3D, 2012’ processed cubes. (a) Time, (b) Depth, (c) Interval velocity and, (d) Time slice. LCC – lowest closing contour. The percentage in (c) shows how much of any one velocity range is represented in the cube.


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Figure 6: Depth structure (differentially processed) – Lower Stairway Sandstone: (a) isotropic TOMO-10 update (stage 2), (b) isotropic TOMO-7 update (stage 3), (c) anisotropic TOMO-7 update (stage 3) and, (d) residual (isotropic TOMO-10 minus ISOTROPIC TOMO-7 update).


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(a)


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(b)


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(c)


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(d)

Figure 7: Seismic inline sections, (a) 1120, (b) 1170 (Surprise-1R), (c) 1220 and, (d) 1320. The seismic section is extracted from the 2nd stage TOMO-10 processed cube.


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(a)


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(b)


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(c)


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(d)

Figure 8: Seismic crossline sections, (a) 5090, (b) 5140 (Surprise-1R), (c) 5190 and, (d) 5240. The seismic section is extracted from the 2nd stage TOMO-10 processed cube.


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Figure 9: TWT Structure (msec-SS) – Mereenie Sandstone. The mapping used the 2nd stage TOMO-10 processed cube. CI – 20 msec.


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Figure 10: TWT structure (msec-SS) – Carmichael Sandstone (unconformity). The mapping used the 2nd stage TOMO-10 processed cube. CI – 20 msec.


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Figure 11: TWT structure (msec-SS) – Stokes Siltstone. The mapping used the 2nd stage TOMO-10 processed cube. CI – 20 msec.


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Figure 12: TWT structure (msec-SS) – Lower Stairway Sandstone. The mapping used the 2nd stage TOMO-10 processed cube. CI – 20 msec.


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Figure 13: TWT structure (msec-SS) – Pacoota Sandstone. The mapping used the 2nd stage TOMO-10 processed cube. CI – 20 msec.


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Figure 14: TWT structure (msec-SS) – Goyder Formation (unconformity). The mapping used the 2nd stage TOMO-10 processed cube. CI – 20 msec.


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Figure 15: TWT structure (msec-SS) – Base Giles Creek Dolostone (unconformity). Note: the Base Giles Creek Dolostone is equivalent to the Petermann Unconformity where the Chandler salt is absent, as is the case in EP-115. The mapping used the 2nd stage TOMO-10 processed cube. CI – 20 msec.


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Figure 16: Depth structure (m-SS) – Mereenie Sandstone. The mapping used the 2nd stage TOMO-10 processed cube. CI – 25 m.


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Figure 17: Depth structure (m-SS) – Carmichael Sandstone (unconformity). The mapping used the 2nd stage TOMO-10 processed cube. CI – 25 m.


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Figure 18: Depth structure (m-SS) – Stokes Siltstone. The mapping used the 2nd stage TOMO-10 processed cube. CI – 25 m.


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Figure 19: Depth structure (m-SS) – Lower Stairway Sandstone. The mapping used the 2nd stage TOMO-10 processed cube. CI – 25 m.


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Figure 20: Depth structure (m-SS) – Pacoota Sandstone. The mapping used the 2nd stage TOMO-10 processed cube. CI – 25 m.


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Figure 21: Depth structure (m-SS) – Goyder Formation (unconformity). The mapping used the 2nd stage TOMO-10 processed cube. CI – 25 m.


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Figure 22: Depth structure (m-SS) – Base Giles Creek Dolostone (unconformity). The mapping used the 2nd stage TOMO-10 processed cube. CI – 50 m.

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Interpretation Report for Seismic Survey ‘Surprise 3D, 2012’ · 2019. 3. 5. · Seismic interpretation ... Table 2: Seismic processing steps for stages 1 to 3 – Time, depth