Study On Fracture Characteristics And Prediction Of Permian Jiamuhe Formation In Xiaoguan Oilfield

Fractures are richly developed in Jiamuhe Formation of Permian,xiaoguai oilfield,frac-tures not only are vital migration channels but also they are reservoir space for oil and gas. This paper research on fracture development,responses,formation causes and main controlling factors by comprehensive utilization of mathematics and geology and statistics methods in Jiamuhe Formation of this region,and use many methods to predict fractures,then comprehensive evaluation of fractures.This paper mainly achieves the following results and understandings:(1)It is a set of thick and compound sedimentary in Xiaoguai area, Jiamuhe formation, which belongs to the onshore alluvial fan-fan delta.The lithology,mainly consist of the massive or lamellar medium to coarse conglomerate, unequal particleconglomerate and small conglomerate.Besides,the reservoir space give priority to dissolved pore, intergranular pores, microfissure, fracture, a spot of interfacial fracture. Moreover,the reservoir type is mainly fracture and fracture-pore type. The reservoir is multiple controlled by sedimentation, diagenesis and structural fracture function,especially the structural fracture function.(2)The results of core fractures observation is the most basic data and the most reliable evidence of fracture prediction.The fractures’ dips are above75°and take more than75percent,mainly standing seam in Jiamuhe formation of permian system,XiaoGuai oilfield.then the high angle fractures with the dip of45°～75°take10%,only a few low angle fractures and horizontal fractures.Large-scale fractures take60percent, Medium-Scale fractures take20percent,while the small-Scale and micro-Scale fractures take only below10percent.The fracture width range mostly from0.1-1mm,taking more than60percent.simultaneously,the fracture density range mostly from0.6-0.8strip per meter. Among them, the unfilled fractures take absolute Superiority with90.5percent.Whereas,the half-filled and full-filled fractures take almost10percent.(3)We also established criteria for identifying effective fractures with conventional logging,comprehensive utilization resistivity,density,acoustic and gamma logging in order to identify fractures.The main controlling factors of the fracture development are structural, lithology and strata thickness.that fractures in Jiamuhe Formation are mostly developed in fine conglomerate,sandy conglomerate,unequal particle sandstone which slone fault zone.but in the middle-crude conglomerate,argillaceous and tuff,fractures are not developed.(4)This article adopt geological,finite element numerical simulation and secsmic phase-interference data precessing method to predict favorable zones.from the geological method,fractures are mainly developed in G102-G5-G105,G103-CP3-G9,C67-C501and G3-G13;from the numerical simulation of paleo-tectonic stress fields, we know that fractures are mainly developed in G102-G5-G105,G103-CP3-G9,C502-C67-C501and G3-G13;from the secsmic phase-interference data precessing, fractures are mostly developed in G5,G103-CP3, G9,C67,G3-G13and Nearby.(5)A comprehensive evaluation about the fracture distribution is presented in the pape, utilizing the method of weighting combined with various results from prediction.It indicated that fracture of I mainly located in the fault area,G102-G5-G105,CP3-G103,G9,G13-G3, C502-C67-C501and the south,generally it behaved like sheets or bands along the fault.