Irawan Y Tribuana, Usep Mulyadi, Agus M Ramdhan, Asep H Rustam


Pore pressure estimation in hard-overpressure zone is very important in drilling activities. Correct and precise estimation are able to reduce the cost for drilling due to reduced non-productive time (NPT) and in increase in safety aspect while drilling. Pore pressure estimation is done by post-mortem analysis in exploration wells using validation points from pressure measurement data such as Drill Stem Testing (DST), Modular Dynamic Tester (MDT), and Repeat Formation Tester (RFT). A wireline logs data used for identification of the type of overpressure and predicts pore pressure magnitude in the shale section. Through the correlation between effective-stress and velocity, a single compaction equation was obtained for the Lower Kutai Basin with the value of : 5.097 * σ 0.854. By using this single equation, pre-drill pore pressure prediction activity will be more easy and could estimate pore pressure in hard-overpressure zone precisesly.


single equation compaction; pore pressure estimation; unloading; hard-overpressure; Lower Kutai Basin

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Barker, C. 1990. Calculated volume and pressure changes during the thermal cracking of oil to gas in reservoirs: AAPG Bulletin, Vol.56, p. 2068 – 2071.

Boles, J., and Franks, S.G. 1979. Clay diagenesis in Wilcox sandstones of southwest Texas : implication of smectite diagenesis on sandstone cementation. Journal of Sedimentary Petrology, 49, 55-70.

Bowers. 1995. Pore Pressure Estimation From Velocity Data : Accounting for Overpressure Mechanism Besides Undercompaction. SPE Drilling & Completion, June 1995.

Dodson. 2009. Eliminating Non-Productive Time Associated with Drilling Trouble Zones. OTC (Offshore Technology Conference) : Houston, Texas.

Eaton, B. A. 1975. The equation for geopressure prediction from well logs. SPE Paper No. 5544.

Fertl, W.H., Chapman, R.E., and Hotz, R.F. 1994. Studies in Abnormal Pressure. Elsevier : New York, USA.

Freed, R.L., and Peacor, D.R. 1989. Geopressure shale and sealing effect of smectite to illite transtition. Bulletin of American Association of Petroleum Geologist, V.73, No.10.

Katahara, K. 2006. Overpressure and shale properties : stress unloading or smectite-ilolite transformation?. 76th SEG Annual Meeting, Expanded Abstracts, 1520- 1524

Mouchet, J-P., and Mitchell, A., 1989. Abnormal Pressures While Drilling. Elf Aquitaine, Boussens, Manual Techniques 2, 255p.

Perry and Hower. 1970. Burial diagenesis in Gulf Coast pelitic sediments. Clay and Clay Minerals. Vol.18, p 165 – 177.

Powers, M.C. 1967. Fluids-release mechanism in compacting marine mudrocks and their importance in oil exploration. AAPG Bulletin 51, p 1240 – 1254.

Swarbrick, R.E., and Osborne, M.J. 1998. Mechanism that generate abnormal pressure : an overview. In : Law, B.E., Ulmishek, G.F. & Slavin, V.I. (eds.) Abnormal Pressure in Hydrocarbon Environment. AAPG, Tulsa, Memoir 70, 13-34.

Swarbrick, R.E., Osborne, M.J., and Yardley, G.S. 2002. Comparison of overpressure magnitude resulting from the main generating mechanism. In : Huffman, A.R. & Bowers, G.L (eds.) Pressure Regimes in Sedimentary Basins and their Prediction. AAPG, Tulsa, Memoir 76, 1-12.

Ramdhan, A.M., and N.R. Goulty, 2011, Overpressure and mudrock compaction in the Lower Kutai Basin, Indonesia – a radical reappraisal. AAPG Bulletin, V. 95, No.10.PP.1725-1744

Rider, M. 2002. The geological interpretation of well logs. Scotland : Rider-French Consulting Ltd.

Tissot, B.P., Pelet, R., and Ungerer, P.H. 1987. Thermal history of sedimentary basins, maturation indices, and kinetics of oil and gas genertion : AAPG Bulletin, Vol.71, p. 227-240.

DOI: https://doi.org/10.29017/SCOG.39.2.105

DOI (PDF): https://doi.org/10.29017/SCOG.39.2.77-90

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