Is there a benefit to throwing the kitchen sink at geotechnical studies in an exploration phase?

2016 ◽  
Vol 56 (1) ◽  
pp. 203
Author(s):  
James Shadlow ◽  
Adam Craig ◽  
David Christiansen
Keyword(s):  
Rock Physics ◽  
Business Case ◽  
3D Seismic ◽  
Avo Inversion ◽  
Volume Assessment ◽  
Exploration Drilling ◽  
Northern Carnarvon Basin ◽  
Seismic Amplitudes ◽  
Well Data ◽  
Gas Fields

In short, yes. This case study illustrates that the application of a thorough geotechnical workflow incorporating many new and advanced techniques can assist in exploration business case decision making. Is an exploration drilling decision made lightly? A workflow incorporating 3D seismic processing, AVO inversion and stratigraphic framework studies involving high-resolution biostratigraphic and chemostratigraphic analyses was used to assess the prospectivity of an exploration permit near giant gas fields in the offshore Northern Carnarvon Basin. The primary reservoir is the prolific Triassic Mungaroo Formation fluvio-deltaic sediments, and secondary reservoirs include mid-Jurassic marine sands. 3D seismic reprocessing xcombined a newly acquired broadband seismic dataset into a multi-survey multi-azimuth PSDM volume that conditioned data for input to an AVO inversion. New petrophysics and rock physics analysis and modelling on regional well data were then calibrated with the AVO inversion to statistically derive lithology and fluid prediction volumes. These data were used in conjunction with reservoir paleo-stratigraphy studies to derive a subsurface model for reservoir distribution and hydrocarbon prediction. A two-stage risking process was applied to each prospect that objectively applied risk based on the seismic amplitudes. This enabled a more accurate risked-volume assessment, combined with the ability to assess a prospect portfolio covering different plays. The resultant interpretation identified issues with interpretations made on vintage data that would not have been easily identified without undertaking these studies. The integration of these assessments resulted in an unfavourable exploration drilling business case and a decision not to renew the permit.

Seismic integrated study for offshore deep- and thin-stratum characterization: A case study from the Enping sag within the Pearl River Mouth Basin

2020 ◽  
Vol 39 (3) ◽  
pp. 176-181
Author(s):  
Jun Liu ◽  
Donghai Liang ◽  
Guangrong Peng ◽  
Xiaomin Ruan ◽  
Yingwei Li ◽  
...  
Keyword(s):  
Seismic Data ◽  
River Mouth ◽  
Rock Physics ◽  
Pearl River ◽  
Pearl River Mouth Basin ◽  
Avo Inversion ◽  
Lithology Prediction ◽  
The Pearl River ◽  
Well Data

In the Enping 17 sag within the Pearl River Mouth Basin in the South China Sea, one wildcat well has been drilled to the Lower Paleogene Enping Formation (FM EP) and partially into the Wenchang Formation (FM WC) for deep formation hydrocarbon exploration. However, no commercial play was discovered. The reasons for this are clear if the petroleum systems modeling is examined. In FM EP, the main reason for failure is due to poor sealing. In FM WC, the failure is due to the lack of a good reservoir for hydrocarbon accumulation. Encountering a 9 m thick reservoir at a depth of 4650 m indicates that braided fluvial delta and lowstand turbidite sandstone may develop in FM WC. With the objective of establishing cap rock in FM EP and reservoir rock in FM WC, and in the absence of sufficient well data, an integrated framework for 3D seismic reservoir characterization of offshore deep and thin layers was developed. The workflow includes seismic data reprocessing, well-log-based rock-physics analysis, seismic structure interpretation, simultaneous amplitude variation with offset (AVO) inversion, 3D lithology prediction, and geologic integrated analysis. We present four key solutions to address four specific challenges in this case study: (1) the application of adaptive deghosting techniques to remove the source and streamer depth-related ghost notches in the seismic data bandwidth and the relative amplitude-preserved bandwidth extension technique to improve the seismic data resolution; (2) a practical rock-physics modeling approach to consider the formation overpressure for pseudoshear sonic log prediction; (3) interactive and synchronized workflow between prestack 3D AVO inversion and seismic processing to predict a 9 m thick layer in FM WC through more than 60 rounds of cyclic tests; and (4) cross validation between seismic qualitative attributes and quantitative inversion results to verify the lithology prediction result under the condition of insufficient well data.

Facies architecture of the K10 supersequence in the Browse Basin: when sequence stratigraphy meets lithostratigraphy

2016 ◽  
Vol 56 (2) ◽  
pp. 568
Author(s):  
Steve Abbott ◽  
Kamal Khider ◽  
Andrew Kelman ◽  
Karen Romine
Keyword(s):  
Seismic Sequence ◽  
Depositional Facies ◽  
Facies Architecture ◽  
Sequence Stratigraphic ◽  
Exploration Target ◽  
Lithostratigraphic Units ◽  
Northern Carnarvon Basin ◽  
Well Data ◽  
Gas Fields ◽  
The Relationship

Regional seismic sequence stratigraphic mapping of the K10 supersequence (Berriasian–Valanginian) has brought into focus the relationship between sequence stratigraphic and lithostratigraphic units. In this extended abstract, the relationship between seismically-defined sandstone bodies and the Brewster Member, an important exploration target and reservoir in the Browse Basin, is investigated. Deposition of the K10 supersequence started at the onset of rifting between Greater India and the Northern Carnarvon Basin. Sediment sourced from uplifted areas resulted in deposition of the Barrow Delta in the Exmouth and Barrow sub-basins. In the Browse Basin, K10 is also a sand-rich progradational sequence, albeit diminutive compared to the Barrow Delta. Seismic mapping of K10 in the Caswell Sub-basin has resolved stratal geometries and, with the integration of well data, recognition gross depositional facies. Sandstone-prone siliciclastic platform facies (clinoform topsets) include the Brewster Member. The first reference to the Brewster Member in the Australian Stratigraphic Units Database applied the name to the upper part of the K10 sequence between 3,284 m and 3,405 m in Heywood–1. Usage of this name, however, has been inconsistently applied to sandstone-prone units within K10. Given the significance of the Brewster Member as an exploration target, and as a reservoir in the Ichthys-Prelude and Burnside gas fields, attention to integration of sequence stratigraphic and lithostratigraphic frameworks for this interval is timely.

The Halladale and Black Watch gas fields—drilling AVO anomalies along Victoria's Shipwreck Coast

2009 ◽  
Vol 49 (1) ◽  
pp. 101 ◽  
Author(s):  
Andrew Constantine ◽  
Glenn Morgan ◽  
Randall Taylor
Keyword(s):  
Joint Venture ◽  
Seismic Survey ◽  
Amplitude Variation With Offset ◽  
Development Scenarios ◽  
Fault Block ◽  
Close Proximity ◽  
Strong Amplitude ◽  
Water Gradient ◽  
Seismic Amplitudes ◽  
Gas Fields

The Halladale and Black Watch fields are adjacent fault-dependent gas accumulations at the Turonian Waarre Formation level situated in the eastern Otway Basin, about 4–5 km from shore in VIC/RL2(v). The two fields were first identified in 2002 when anomalous seismic amplitudes were observed on the tail-ends of several 90s-vintage 2D lines that extended into what was then vacant acreage. After being awarded the block as VIC/P37(v) Origin Energy Limited and its joint venture (JV) partner, Woodside Energy Limited, acquired a 211 km2 full-fold 3D seismic survey over the anomalous amplitudes in late 2003. Subsequent analysis of the seismic volume revealed two tilted fault blocks with strong amplitude variation with offset (AVO) anomalies in the Waarre A and Waarre C units that conformed to structure and appeared to shut off at the same depth. A similar AVO anomaly was also observed in the overlying Santonian Nullawarre Formation, raising the possibility that Halladale and/or Black Watch had leaked or were leaking. In early 2005, the VIC/P37(v) JV drilled two exploration wells targetting the key Waarre C reservoir on the eastern flank of Halladale and eastern crest of Black Watch. Both wells encountered live gas columns in the Waarre C but no GWCs were observed on logs and wireline pressure data indicated the two fields were not in pressure communication. A third well was then drilled down-dip of the Waarre C AVO shut off on the Halladale fault block to obtain a water gradient from the Waarre C. This well proved invaluable in determining the height of the gas columns in the Waarre C at both fields as it showed the gas-water contacts (GWCs) at Halladale (1,760 mSS) and Black Watch (1,770 mSS) were shallow to their respective AVO shut offs by about 20 m and 10 m respectively. Subsequent analysis of shear wave sonic data from the third well indicated there is a 17 m residual gas column at the base of the Halladale Field. This suggests Halladale either leaked slightly at some time in the past or is still leaking. A similar scenario may also occur at Black Watch. Given the close proximity of the two fields to the coast, development scenarios from onshore are now being considered.

Fault-seal potential of the Palaeozoic in the northwest Canning Basin

2012 ◽  
Vol 52 (1) ◽  
pp. 427
Author(s):  
Julian Strand ◽  
Antoine Vaslin ◽  
Laurent Langhi
Keyword(s):  
Injection Site ◽  
Western Australia ◽  
Co2 Sequestration ◽  
Hydrocarbon Exploration ◽  
Early Permian ◽  
North West ◽  
Canning Basin ◽  
Price Point ◽  
Exploration Drilling ◽  
Gas Fields

As part of a Geological Survey of Western Australia organised review of the Canning Basin involving UWA and CSIRO, the fault-seal potential for the northwest Canning Basin has been analysed. This study has two foci: firstly identifying potential for fault-bound hydrocarbon reservoirs in the Early Permian (Poole Sandstone and Upper Grant Group). Secondly, James Price Point, 55 km north of Broome, is the chosen location for an LNG facility to service the northern North West Shelf gas fields. As such, the study aims to highlight potential CO2 sequestration reservoir sequences occurring inside 200 km of James Price Point, the economically feasible distance for CO2 delivery to an injection site. Historically, hydrocarbon exploration drilling in the Fitzroy Trough targeted anticlinal structures, which proved unsuccessful due to localised, but significant, erosion of the Permian sequence including the Noonkanbah Formation top-seal on anticlinal crests. Given there is potential for untested, fault-bound traps to exist, which might provide an alternative to the anticlinal traps, it will be useful to identify the distribution of shale-rich, top-seal and fault-seal prone sequences, and where these occur at suitable reservoir depths. The study shows the Early Permian sequences on the flanking terraces of the Fitzroy Trough commonly have suitable top-seal and fault-seal prone sediments. In wells analysed in the Fitzroy Trough itself, the Early Permian sequence is poorly represented, but Permo-Carboniferous sediments observed indicate some sealing potential might exist there. Moving south onto the Broome Platform and into the Wiluna Sub-basin, the Early Permian sequences still display some sealing potential, but Ordovician units might provide more suitable targets for sequestration in these areas.

Sign in / Sign up

Export Citation Format

Share Document