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Characteristics of the Strike Slip Fault and its Control on Hydrocarbon Accumulation in the Ordovician Carbonate of the Central Tarim Uplift, China

Yanping Zhang¹, Xiuxiang Lü¹, Haijun Yang², Hongfeng Yu², and Guojuan Cao²
¹State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing, China
²Exploration and Development Institute of Tarim Oilfield Company, PetroChina, Korla, Xinjiang, China

The Ordovician carbonate in the Central Tarim Uplift has great exploration potential as one of the main plays that increases reserves and production of the Tarim Oil Field in recent years, but it was found that the oil-gas-water distribution is very complicated along with the progress of exploration. Strike slip fault activity significantly affected hydrocarbon accumulation in the Ordovician of the Central Tarim Uplift, but previous research is less than adequate.

This paper focuses on strike slip fault research on the basis of seismic interpretation, to reveal strike slip fault distribution and activity, to explore the control of strike slip fault on hydrocarbon accumulation of the Ordovician in terms of formation and reform of carbonate reservoir beds and hydrocarbon distribution.

On the basis of three-dimensional seismic data, Semblance description for deep fault, seismic interpretation and layer flattening analysis were used to study strike slip faults. The structural styles of strike slip fault include flower structure, en echelon structure and pull-apart graben. Five stages of strike slip fault activity since the Ordovician include the Middle Ordovician, the Late Ordovician, the Silurian-Devonian, the Permian and minor adjustment of strike slip faulting activity of the Cenozoic.

On the basis of thin section, core, logging and seismic data, our study utilized the seismic attribute reservoir bed prediction technique and fracture-cave carving technique. It was found that the lateral control range of strike slip fault on the development of carbonate reservoir bed was within 8.0km, more obviously within 0.2-4.5 km. The vertical control range was within 305m, more obviously within 220m.

Inclusion, well logging, well testing and geochemical parameters indicated that the convergence of strike slip faults with thrust faults and the extensional stress field of strike slip faults at different period of activities were the charging point, which controlled the hydrocarbon distribution of corresponding accumulation timing. In the area near the main strike slip faults from 1.0km to 6.0km, the closer with the main strike slip fault, the higher the well production.

In a word, the main strike slip fault activity in different period acted as vertical migration pathway between ∈-O marine source rocks and O1y-O3l reservoir beds on the basis of constructive reform of carbonate reservoir beds, and the branch strike slip fault play the role of lateral shunt.

AAPG Search and Discovery Article #90175©2013 AAPG Hedberg Conference, Beijing, China, April 21-24, 2013