Study On The Characteristics Of Chang 8 Reservoir In Ansai Nan,Ordos Basin

Zhidandong-Hechuangping area of Ansai oilfield is located in northern Shaanxi,which is structurally located in the middle and southern part of the slope of northern Shaanxi,with a whole west dipping monocline with high east and low west.In this paper in view of the research district 8 reservoir,low permeability and accumulation regularity of complex oil and gas filling such outstanding problems as inadequate,make full use of agent evaluation Wells and development Wells in this area such as static and dynamic data,describe the research district 8reservoir sedimentary microfacies and sand body distribution rule,comprehensive evaluation of reservoir and block optimization and potential.The following important conclusions and cognition have been obtained from the study:1.Through the study of sedimentary facies markers,it is clear that the Chang8 area in the study area develops delta front deposits,and the underwater distributary channel sand body is the dominant aggregate,which is distributed in a NE-SW direction.2.Research district 8 reservoir is given priority to with fine-grained feldspar sandstone and feldspathic litharenite,filler content of 13%on average,mainly for iron mica is given priority to,calcite,chlorite and water pore types mainly intergranular pore and feldspar dissolved pore,face an average rate of 3.3%,reservoir property belongs to low permeability reservoir is given priority to,locally developed relatively high porosity,high permeability zone.3.Based on the evaluation results of sedimentary,diagenesis and pore structure characteristics of Chang 8 in the study area,the diagenetic facies in the study area can be divided into four types,among which chlorite film cementation-intergranular pore and hydromica cementation-feldspar dissolution diagenetic facies are the favorable diagenetic facies.4.The research district 8 reservoir comprehensive evaluation is divided into four major categories,5 classes,including?,?reservoir oil saturation is high,the testing effect is good,comprehensive evaluation for the high quality reservoirs.5.In view of Nanchang 8 reservoir in Ansai,a total of 17 favorable areas for production and construction were screened,with a predicted oil bearing area of 108.3km2 and a predicted geological reserve of 3452.8×10~4t.It is suggested to deploy a total of 16 exploration and evaluation Wells in 7 favorable target areas.