1887
Volume 54 Number 1
  • E-ISSN: 1365-2478

Abstract

ABSTRACT

In the Southern Gas Basin (SGB) of the North Sea there are many mature gas fields where time‐lapse monitoring could be very beneficial in extending production life. However, the conditions are not immediately attractive for time‐lapse seismic assessment. This is primarily because the main production effect to be assessed is a pore pressure reduction and frame stiffening because of gas production in tight sandstone reservoirs that also have no real seismic direct hydrocarbon indicators. Modelling, based on laboratory measurements, has shown that such an effect would be small and difficult to detect in seismic data. This paper makes two main contributions. Firstly, this is, to our knowledge, the first time‐lapse study in the SGB and involves a real‐data assessment of the viability for detecting production in such an environment. Secondly, the feasibility of using markedly different legacies of data in such a study is addressed, including an assessment of the factors influencing the crossmatching. From the latter, it is found that significant, spatially varying time shifts need to be, and are successfully, resolved through 3‐D warping. After the warping, the primary factors limiting the crossmatching appear to be residual local phase variations, possibly induced by the differing migration strategies, structure, reverberations and different coherencies of the volumes, caused by differences in acquisition‐structure azimuth and acquisition fold. Despite these differences, a time‐lapse amplitude signature is observed that is attributable to production. The character of the 4‐D amplitude anomalies may also indicate variations in stress sensitivity, e.g. because of zones of fracturing. Additionally, warping‐derived time attributes have been highlighted as a potential additional avenue for detection of pressure depletion in such reservoirs. Although the effects are subtle, they may indicate changes in stress/pressure in and around the reservoir because of production. However, to fully resolve the subtle time‐lapse effects in such a reservoir, the data differences need to be better addressed, which may be possible by full re‐processing and pre‐stack analysis, but more likely dedicated 4‐D acquisition would be required.

Loading

Article metrics loading...

/content/journals/10.1111/j.1365-2478.2006.00515.x
2005-12-09
2020-04-02
Loading full text...

Full text loading...

References

  1. DruzhininA. and MacBethC.2001. Robust cross‐equalization of 4‐D 4‐C PZ migrated data at Teal South. In 71st Ann. Internat. Mtg , Soc. of Expl. Geophys , pp. 1670–1673.
    [Google Scholar]
  2. HallS.A., MacBethC. and BarkvedO.I.2003. Warping and 4D deformation monitoring. In 73rd Annual Internat. Mtg., Soc. Expl. Geophys., postconvention workshop abstracts .
  3. HallS.A., MacBethC., BarkvedO.I. and WildP.2002. Time‐lapse seismic monitoring of compaction and subsidence at Valhall through cross‐matching and interpreted warping of 3D streamer and OBC data. In 72nd Annual Internat. Mtg., Soc. Expl. Geophys., Expanded Abstracts .
  4. HallS.A., MacBethC., BarkvedO.I. and WildP.2005. Cross‐matching with interpreted warping of 3D streamer and 3D OBC data at Valhall for time‐lapse assessment. Geophysical Prospecting, 53, 283–297.
    [Google Scholar]
  5. HatchellP., SayersC., Beukelvan denA., MolenaarM., MaronK., KenterC., StammeijerJ. and Veldevan derJ.2003. Whole earth 4D: Monitoring geomechanics. In 73rd Annual Internat. Mtg., Soc. Expl. Geophys., Expanded Abstracts , 1330–1333.
  6. JohnstadS.E., SeymourR.H. and SmithP.J.1992. Seismic reservoir monitoring over the Oseberg field during the period 1989‐1992. First Break, 13, 169–183.
    [Google Scholar]
  7. LandroM., SolheimO.A., HildeE., EkrenB.O. and StronenL.K.1999. The Gullfaks 4D seismic study. Petroleum Geoscience, 213–226.
    [Google Scholar]
  8. MacBethC.StammeijerJ. and OrmerodM.2003. A petroelastic‐based feasibility study of monitoring pressure depletion in a UKCS gas reservoir. In 73rd Ann. Internat. Mtg., Soc. Expl. Geophys., Extended Abstracts .
  9. MooreP.J.R.M.1989. Barque and Clipper: well test analysis in low‐permeability fractured gas reservoirs. SPE, 18966, 379–390.
    [Google Scholar]
  10. MulderG.BuschV.L.P.ReidI.Sleeswijk VisserT.J. and HeystvanB.G.1992. Sole Pit: improving performance and increasing reserves by horizontal drilling. SPE25025, 83–94.
    [Google Scholar]
  11. RickettJ. and LumleyD.E.2001. Cross‐equalisation data processing for time‐lapse seismic reservoir monitoring: A case study from the Gulf of Mexico. Geophysics66, 1015–1025.
    [Google Scholar]
  12. WattsG.F.T.JizbaD.GawithD.E. and GutteridgeP.1996. Reservoir monitoring of the Magnus field through 4D time‐lapse seismic analysis. Petroleum Geoscience361–372.
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journals/10.1111/j.1365-2478.2006.00515.x
Loading
/content/journals/10.1111/j.1365-2478.2006.00515.x
Loading

Data & Media loading...

  • Article Type: Research Article
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error