--> ABSTRACT: Abnormal Fluid Pressure and Compartmentalization in Tarim Basin, China, by X. Huang and Q. Wang; #91021 (2010)

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Abnormal Fluid Pressure and Compartmentalization in Tarim Basin, China

HUANG, XIAOMING, and QIZONG WANG

Studies have addressed the problems of hydrocarbon accumulation and re-distribution in deep basin within the abnormal fluid pressure regimes. This is the first paper concerning the pressure compartment in Tarim basin and Tazhong, Yingmaili and Lunnan oilfields are the three major case study areas.

Overpressured shale was mapped throughout two study areas i.e. Tazhong and Yingmaili oilfield. Well logs and clay mineral show overpressured shale of Permian and Carboniferous formations between 2800 to 3800 meters in Tazhong area. No hydrocarbon accumulations have yet been found beyond the pressure compartment which we presented early, geochemical evidence and oil-gas reservoirs distribution in Tazhong area indicate that the thermal-cracking of oil to gas had occurred two times since the origin oil-reservoir occurrence. The overpressured shale of upper Paleozoic in Yingmalli area is 1000 meters deeper than that in Tazhong area. Some normal pressured Ordovician oil-reservoirs are underlaying the overpressure seal. In the northeast region of Yingmaili where absent this overpressure seal so that the hydrocarbon accumulations are found in Mesozoic-Cenozoic formations. The vertical and multilateral compartmentalizations because of complex deposition conditions in Lunnan area derived many anomalous oil-gas reservoirs including both overpressured and underpressured reservoirs. Detailed studies of thermal history, bury history, geochemistry and well logs have been done and helped us to understand the mechanism of these compartmentalizations.

This research is funded by the invention-fund project of China National Petroleum Corporation, 1996-1997, and was supported by Tarim Petroleum Exploration Company, 1995.

AAPG Search and Discovery Article #91021©1997 AAPG Annual Convention, Dallas, Texas.