Print this pagePrediction of High-Producing Accumulation of Super-Tight Sandstone Reservoir in Upper Triassic in Sichuan Basin of China
Xinchang Gas field lies on the Xinchang structure with NE-E trending of Xiaoquan-Fenggu uplift in Western Sichuan depression in Sichuan basin. The gas reservoirs, formed in the 2nd member of Xujiahe Formation (T3x2), are characterized by the following 6 points including 1.Super-deep. 2.Thick and big sand bodies with steadily distributed delta front facies , super-tight, low porosity, low permeability. 3. Structures were formed lately. 4. Overpressure. 5. Complicated gas-water interface. 6. Heterogeneous reservoir. All of these characteristics prove that it’s difficult to explore the 2nd member of Xujiahe Formation (T3x2) in Xinchang Gas field. Conventional seismic technologies are facing big challenges under the tough seismic-geologic conditions. Converted wave 3D3C (three-component and three-dimension) seismic is propitious to explore the deep tight sandstone gas reservoir due to converted wave and compressed wave, which can be acquired simultaneously.
In 2005, the technique of 3D3C seismic exploration was deployed and implemented in main part of Xinchang reservoir. By using abundant 3D3C seismic data, doing multi-component joint data processing, inversion, multi-component attributes analysis and integrated interpretation for the target of the high producing accumulation bed in Xinchang gas field, problems such as better gas-bearing bed recognition and fracture network detection etc. can be solved effectively.
This article focus on the research on synthetically analyzing the basic geological characters of the 2nd member of Xinchang Xujiahe Formation (T3x2) and main control factors of gas-bearing bed.We fully applied PP and PS waves information of 3D3C seismic data, synthetically studied cause of formation from geological history for fracture detection, P wave attributes for fracture detection, P wave azimuthal anisotropy for fracture detection, S wave splitting for fracture detection, PP and PS waves joint inversion for gas-bearing bed recognition, Poisson’s ratio and P wave impedance joint display for gas-bearing bed recognition. These techniques effectively resolved the problems of high producing accumulation bed prediction of tight sandstone reservoir in Xujiahe Formation. There have been completed drilling 8 wells aiming at the 2nd member of Xujiahe Formation (T3x2) in Xinchang gas field, 6 of which have got gas production, and 3 wells are of high production with over 500,000 cubic meters daily yields.
AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil