Fracture characteristics in Qingxi Oilfield,Jiuquan Basin
Sun Xing1,2,4, Pan Liang-yun1, Yan Qun1, Zhao Jian-ru1, Wei Jun3, Fang Chen3
1. BGP Geological Research Center,CNPC, Zhuozhou, Hebei, 072751, China;
2. College of Earth Resource and Information, China University of Petroleum(China East), Qingdao, Shandong, 266555, China;
3. Research Institute of Exploration and Development,Yumen Oilfield, Yumen, Gansu, 735200, China
Abstract：From the core and logging data,in this article fracture types and microscopic features are analyzed in Qingxi Oilfield,Jiuquan Basin.Fracture distributions and their relation with geological structure are discussed based on regional tectonic background by seismic attributes,drilling and log data.The following observations are obtained.1.Massive sandstone and argillaceous dolomite in the Xiagou of lower Cretaceous are typical low porosity and low permeability reservoirs.Fractures are major hydrocarbon pore volumes and migration pathways.Various types of tectonic fractures are developed,but the high angle fracture and oblique fractures are the most effective to oil and gas accumulation.2.Faults control the fracture development direction.The direction of fracture development belt and that of fault development belt are basically same,mainly to the NNE and NWW.3.The position of tectonic transition and fault intersection is a center of tectonic stress concentration and fracture development.4.Crack growth controls oil and gas enrichment.The crack belt of NNE adjusting faults is an oil and gas enrichment zone.Using fracture prediction result,the newly defined Well L104 acquires high-productive oil flow with 64m3 per-day.
