Prediction and evaluation of abnormal formation pressure and fracture pressure in ‘Maria’ field, deep offshore, Niger delta

  • Authors

    • Ajibade A.M Obafemi Awolowo University, Ile Ife.
    • Enikanselu P. A. Federal University of Technology, Akure.
    • Olowokere M.T Obafemi Awolowo University, Ile Ife.
    2019-05-27
    https://doi.org/10.14419/e.v2i1.11476
  • Use about five key words or phrases in alphabetical order, Separated by Semicolon.

  • This work aimed at the establishment of pore pressure generation mechanisms and pore pressure prediction for the "Maria†Field, Niger Delta. The objectives are therefore to isolate the pressure behaviour of the reservoir of interest in the study area and build a robust geological pressure model; predict pore pressure; and identify overpressure zones from pressure/depth plots with supporting evidence from drilling and mud log data.

    A velocity cube was built by geostatistically mapping the available well-log data in the area, constrained by depth horizons and a 3D trend. The velocity volume was calibrated with checkshot data from an offset well. The calibrated velocity-to-pressure transform was then applied to the trend-krigged velocities. To apply the pore-pressure transform, density at all locations were determined to calculate 3D volume of pressure.

    Well log data from Four (4) wells within the study area were used to determine the compaction trend using shale acoustic parameters and depth, and to establish pressure mechanism and predict overpressure depth. Normal Compaction Trend (NCT) were drawn by fitting of trend lines to the interval velocity, porosity and density data as a function of depth below mudline. Pressure data in the form of repeat formation test (RFT), Leak of Test (LOT), and mud weight (MW) data were used in this study to calibrate the prediction.

    The top of overpressure were determined in Maria-001, -014 and -015 as 3749.04 m (12300ft), 2727.96 m (8950ft) and 2712.72 m (8900ft) respectively. Maria-004 well revealed normal pressure trend from plotted pressure data. At shallow depths, the subsurface stratigraphy follows normal compaction trend (NCT) from well and seismic velocity models. However, the shifts from the NCT, as observed from resistivity, sonic velocity and porosity, indicated under-compaction of sediments as the cause of the abnormal pressure in the field. The predicted pore pressures were compared with offset well data and good match were observed. The results of this study lead to an understanding of the subsurface pressure distribution. There is velocity reversal with density increase as in Maria-001, 014 and 015 wells this is most likely indicative of undercompaction as the cause of the abnormal pressure. In Maria-001 where the velocity decreases with constant density values, secondary pressure is likely to be the cause of the abnormal pressure. Overpressure mechanism analysis using velocity-density cross-plot techniques showed that the plots have negative trends in three wells namely Maria-001, -004, and -014. Velocity reduction were observed in the three wells which suggests that Disequilibrium compaction was the only primary mechanism that created overpressure. Lateral transfer along faults and connected reservoir systems also could have contributed to overpressure generated from deep processes as shown in Maria-004.

     

     


     

  • References

    1. [1] Alixant, J.L. and Desbrandes, R. (1991): “Explicit Pore-Pressure Evaluation: Concept and Application,†SPEDE p. 182. https://doi.org/10.2118/19336-PA.

      [2] Ajakaiye, D.E. & Bally, A.W. 2002a.Course manual and atlas of structural styles on reflection profiles from the Niger Delta. American Association of Petroleum Geologists, Continuing Education Course Note Series, 41. https://doi.org/10.1306/CE41915.

      [3] Bilotti, F. & Shaw, J.H. 2005. Deep-water Niger Delta fold and thrust belt modeled as a critical-taper wedge: The influence of elevated basal fluid pressure on structural styles. American Association of Petroleum Geologists Bulletin, 89, 1475–1491. https://doi.org/10.1306/06130505002.

      [4] Bilotti, F., Shaw, J.H., Cupich, R.M. &Lakings, R.M. 2005. Detachment fold, Niger Delta. In: Shaw, J.H., Connors, C. & Suppe, J. (eds) Seismic interpretation of contractional fault-related folds. American Association of Petroleum Geologists, Studies in Geology, 53, 103–104.

      [5] Briggs, S.E.,Davies, R.J., Cartwright, J.A. & Morgan, R. 2006. Multiple detachment levels and their control on fold styles in the compressional domain of the deepwater west Niger Delta. Basin Research, 18, 435–450 https://doi.org/10.1111/j.1365-2117.2006.00300.x.

      [6] Bolas, H.M.N., Hermanrud, C and Teige, G.M.G.: 2004.Origin of overpressures in shales: constraints from basin modelling; AAPG Bulletin, vol.88, no.2; pp.193- 211. https://doi.org/10.1306/10060302042.

      [7] Bourgoyne, A.T. Jr, and Rocha, A.L. Jr. (1996):

      [8] Caillet, G., and S.Batiot.: 2003. 2-D modelling of hydrocarbon migration along and across Growth faults: An example from Nigeria: Petroleum Geoscience, vol.9; pp.113-124. https://doi.org/10.1144/1354-079302-499.

      [9] Carcione, J.M., and H.B. Helle, 2002, Rock physics of geopressure and prediction of abnormal pore fluid pressure using seismic data: CSEG Recorder, v. 27/7, p. 8-32.

      [10] Chopra, S, and A. Huffman, 2006, Velocity determination for pore pressure prediction: Leading Edge, v. 25/12, p. 1502-1515. https://doi.org/10.1190/1.2405336.

      [11] Clegg, P., 2011, Understanding Overpressure and its Prediction, Training Module: IPA.

      [12] Corredor, F.H., Shaw, J.H. &Bilotti, F. 2005a. Structural styles in the deep-water fold and thrust belts of the Niger Delta. American Association of Petroleum Geologists Bulletin, 89, 753–780. https://doi.org/10.1306/02170504074.

      [13] Corredor, F.H., Shaw, J.H. &Suppe, J. 2005b. Shear fault-bend fold, deep water Niger Delta. In: Shaw, J.H., Connors, C. &Suppe, J. (eds) Seismic interpretation of contractionalfault-related folds. American Association of Petroleum Geologists, Studies in Geology, 53, 87–92.

      [14] Crain, E. R. (1986). The log analysis handbook. Tulsa, OK: Penn-Well.

      [15] Desbrandes, R. (1985). Encyclopedia of well logging. Houston, TX: Gulf.

      [16] Doust and Omatsola (1990).

      [17] Eaton, B.A. (1975): “The Equation for Geopressure Prediction from Well Logs,†paper SPE 5544 presented at the 1975 SPE Annual Technical Conference and Exhibition, Dallas, TX, September 28 – October 1. https://doi.org/10.2118/5544-MS.

      [18] Hilchie, D. W. (1982). Advanced well logging interpretation. Golden, CO: D.W.

      [19] Hoesni, M.J., Swarbrick, R. E, and Goulty, N. R (2003). The Origins of overpressure in the Malay Basin AAPG Barcelona Conference, Spain.

      [20] Hottman, C.E., and Johnson, R.K.: “Estimation of Formation Pressures from Log-derivedShale Properties,†JPT, June 1965, p. 717 https://doi.org/10.2118/1110-PA.

      [21] http://www.onepetro.org/mslib/app/Preview.do?paperNumber=00005544&societyCode=SPE

      [22] Indrelid, S.L., 1997.A guide to the prediction of pressures from seismic velocities; SIEP-97-5790.

      [23] Iverson etal.,1994.

      [24] Krusi, H.R., 1994.Overpressure prediction; A contribution towards safer drilling; Nigeria Association of Petroleum Explorationists Bulletin, vol.9; pp.86 –91.

      [25] Krueger, S.W. & Grant, N.T. 2006.Evolution of fault-related folds in thecontractional toe of the deepwater Niger Delta. Paper presented at the AAPG Annual Convention, 9–12 April, Houston, Texas. Search and Discovery, article #40201, available on the World WideWebathttp://www.searchanddiscovery.net/documents/2006/06060krueger/index.htm.

      [26] Krueger, S.W., Snyder, F.C., Grant, N.T., Beeley, H.S., Maler, M., Parry, C.C. & Solomon, S. 2005. Evolution of fault-related folds in the contractional toe of the deepwater Niger Delta (abstract). In: Proceedings of the International Conference on Theory and Application of Fault-Related Folding in Foreland Basins, Beijing, China. PetroChina Ltd and Princeton University, 43–44.

      [27] Law, B.E., R.M. Pollastro., and C.W. Keighini.: 1986. Geologic characterization of low permeability gas reservoirs in selected wells, greater green river basin, Wyoming, Colorado and Utah, in C.Spencer and R.Mast, eds., geology of tight gas reservoirs ; AAPG Studies in geology; vol.29;pp.253-269.

      [28] Morgan, R. 2003. Prospectivity in ultradeep water: the case for petroleum generation and migration within the outer parts of the Niger Delta apron. In: Arthur, T.J., McGregor, D.S. & Cameron, N.R. (eds) Petroleum Geology of Africa: new themes and developing technologies. Geological Society, London, Special Publications, 207, 151–164. https://doi.org/10.1144/GSL.SP.2003.207.8.

      [29] NFOR, Bruno Ndichoet al., (2011). Porosity as an overpressure zone indicator in an X-field of The Niger Delta Basin, Nigeria Arch. Appl. Sci. Res., 2011, 3 (3):29-36.

      [30] Nwaufa, W.A., Horsfall, D.E., and Ojo, C.A.: 2005.Advances in deep drilling in the Niger delta,1970-2005: NAOC Experience, NAPE Conference Proceedings, August 2006, pp.5- 14.

      [31] Olatunbosunetal., (2014). Detecting and Predicting Over Pressure Zones in the Niger Delta, Nigeria: A Case Study of Afam Field. Journal of Environment and Earth Science ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online). Vol. 4, No.6, 2014.

      [32] Oilfield review, 2005.

      [33] Reda, M. A., Ghorab, M. A., and Shazly, T. F. (2003). Determination of permeability and density and nature of fluids of some Miocene-Pre Miocene rocks in the central Gulf of Suez. Egypt. J. Appl. Geophys. 2:129–138.

      [34] Said, R. (1990). The geology of Egypt. Rotterdam, the Netherlands: Brookfield.

      [35] Schieber, J., Zimmerle, W., and Scthi, P. (1998). Shale and mudstone (Vols. 1 and 2). Stuttgart, Germany: Schweizerbart’scheVerlag

      [36] Schlumberger. (1986). Repeat Formation Tester. Princeton Junction, NJ:

      [37] Shaker, S., 2007, Calibration of Geopressure Predictions using the Normal Compaction Trend: Perception and Pitfall: CSEG Recorder, 7 p.

      [38] Shaker, S. S. 2012: Drilling Challenges due to the disparity between reservoir and seal pressure gradient: Based on a case Histories from Gulf of Mexico, American Association of Drilling Engineers AADE-12-FTCE-66.

      [39] Shaker, S. S., 2007, the precision of normal compaction trend delineation is the key stone of predicting pore pressure. AADE-07-NTCE-51.

      [40] Swarbrick, R.E., Osborne, M.J. & Yardley, G.S. 2002.Comparison of overpressure magnitude resulting from the main generating mechanisms.In: Huffman, A.R. & Bowers, G.L. (eds) Pressure regimes in sedimentary basins and their prediction. American Association of Petroleum Geologists Memoir, 76, 1–12.

      [41] Swarbrick, R.E, 2002, Challenges of Porosity-based Pore Pressure Prediction: CSEG Recorder, 4 p.

      [42] Ward, C.: 1995. Evidence for sediment unloading caused by fluid expansion overpressure generating mechanisms, in M. Fejerskov, and A.M. Myrvang, eds., Proceedings of the Workshop on Rock Stress in the North Sea; Trondheim, Norway, SINTEF and the University of Trondheim,13 –14 February; pp.218 –231.

      [43] Workshop Module, 2007, Pore Pressure Prediction and Wellbore Stability Workshop: Knowledge System, Nov 7th-8th, 2007.

      [44] Yoshida, C., et al.: “An Investigative Study of Recent Technologies Used for Prediction, Detection, and Evaluation of Abnormal Formation Pressure and Fracture Pressure in North and South America,†IADC/SPE 36381 presented at the 1996 IADC/SPE Asia Pacific Drilling Technology Conference, Kuala Lumpur, Malaysia, September 9 – 11. https://doi.org/10.2118/36381-MS.

  • Downloads

  • How to Cite

    A.M, A., P. A., E., & M.T, O. (2019). Prediction and evaluation of abnormal formation pressure and fracture pressure in ‘Maria’ field, deep offshore, Niger delta. SPC Journal of Energy, 2(1), 1-17. https://doi.org/10.14419/e.v2i1.11476