Predicting Abnormal Formation Pressure Using 3D Seismic Velocity, in Kupal Oil Field

Document Type : Research Paper

Authors

1 Geology Department, Earth Sciences Faculty, Shahid Chamran University of Ahvaz, Iran

2 Geology Department, National Iranian South Oil Company (NISOC), Ahvaz, Iran

Abstract

Pore pressure prediction is important in hydrocarbon exploration, production, and drilling activities. The presence of abnormal pressure may cause different problems such as pipe stuck, well blow out, mud loss, and so forth. Using seismic data is the only method for pore pressure prediction before drilling. In the present paper, stacking velocity which has been obtained from 3D seismic data processing was calibrated with acoustic log. The effective pressure was determined using Bower´s equation. Pore pressure would be predicted by overburden pressure and basic Terzaghi´s equation as well as abnormal pressure zones if existed. The results indicated that there have been two abnormal pressure zones existed in the Kupal Oilfield: high pressure zone in Gachsaran Formation (Member 1 or cap rock), in Pabdeh Formation, and two low abnormal pressure zones in the upper part of Asmari Formation. Pore pressure in Lower Asmari section is higher than in the upper part due to higher porosity.
 

Keywords

Main Subjects


[1]. Chopra S. and Huffman A. R., “Velocity determination for pore pressure prediction,” The Leading Edge, Vol. 23(12), pp.1502-1515, 2006. ##
[2]. Dutta N., Mukerji T., Prasad M. and Dvorkin J., “Seismic detection and estimation of overpressure Part I: The rock physics basis,” CSEG Recorder, Vol. 27(7), pp. 58-73, 2002. ##
[3]. Pennebaker E. S., “Seismic data indicate depth, magnitude of abnormal pressure,” World Oil, Vol. 166, pp. 73–78, 1968.##
[4]. Fillippone W. R., “Estimation of formation parameters and the prediction of overpressure from seismic data,” Presented at the SEG Research Symp. Geo-pressure Studies, Paper R1.4, Dallas, TX, Oct. 17-21, pp. 502-503, https://doi.org/10.1190/1.1827121, 1982.##
[5]. Wang Z. and Wang R., “Pore pressure prediction using geophysical methods in carbonate reservoirs: Current status, challenges and way ahead,” Journal of Natural Gas Science and Engineering, Vol. 27, pp. 986-993, 2015 ##
[6]. Terzaghi K., “Theoretical soil mechanics,” John Wiley and Sons, Inc. 526P. ISBN 0-471-85305-4, 1943.##
[7]. Sayers C. M., “An introduction to velocity-based pore-pressure estimation,” The Leading Edge, Vol. 25(12), pp.1496-1500, 2006.
[8]. Sherkati S. and Letouzey J., “Variation of structural style and basin evolution in in the central Zagros Izeh zone and Dezful Embayment, Iran,” Marine and Petroleum Geology, Vol. 21, pp. 535–554, 2004.##
[9]. Traugott M., “Pore/fracture pressure determinations in deep water,” World Oil, Vol. 218(8), pp.68-70, 1997. ##
 [10] Chen T. and Guan Z., “Theory and technology of drilling engineering”, The Press of the University of Petroleum, Dongying (China), pp. 166-211, 2000. ##
[11]. Gardner G. H. F., Gardner I. W. and Gregory A. R., “Formation velocity and density-the diagnostic basics for stratigraphic traps,” Geophysics, Vol. 39 (6), pp. 770-780, 1974.##
[12]. Tosaya C. A., “Acoustical properties of clay-bearing rocks”, PhD Thesis, Dept. of Geophysics, School of Earth Sciences, Stanford University, USA. p. 147, 1982.##
[13]. Tosaya C. and Nur A., “Effects of diagenesis and clays on compressional velocities in Rocks”,Geophysical Research Letters, Vol. 9, pp. 5–8, 1982.##
[14]. Dvorkin J., Moos D., Packwood J. L. and Nur A. M., “Identifying patchy saturation from well logs”, Geophysics, Vol. 64 (6), pp.1756-1759, 1999.##
[15]. Eaton B.A., “Graphical method predicts geo-pressure worldwide”, World Oil, Vol. 182, pp.51-56, 1972.##
[16]. Bowers G., “Pore pressure estimation from velocity data: According for overpressure mechanism besides undercompaction”, SPE Drilling and Completion, Vol. 10 (2), pp. 89-95, 1995.##
[17]. Sayers C., Johnson G. and Denyer G., “Predrill pore-pressure prediction using seismic data”, Geophysics, Vol. 67(4), pp.1286-1292, 2002. ##
[18]. Dix C. H., “Seismic velocities from surface measurements,” Geophysics, Vol. 20, pp.68–86, 1955.##
[19]. Lee S., Shaw J., Ho R., Burger J., Singh S. and Troyer B., “Illuminating the shadows: tomography, attenuation and pore pressure processing in the South Caspian Sea,” Journal of Petroleum Science and Engineering, Vol. 24(1), pp. 1-12, 1999. ##
[20]. Kelly M. C., Skidmore C. M. and Cotton R. D., “Pore pressure prediction for large surveys,” SEG Expanded Abstracts, Vol. 24, pp. 1239-1243, 2005.##
[21] نصرت ا.، «پیش‌بینی فشار منفذی توسط نشانگرهای لرزه‌ای سه‌بعدی»، پایان‌نامه کارشناسی ارشد مهندسی اکتشاف نفت، دانشکده مهندسی معدن، متالوژی و نفت، دانشگاه صنعتی امیرکبیر، 1386.##