Study On Stable Production Technology Of The Chang 8₁ Reservoir In Zhuang 9 District

This paper takes the Chang 8 Member Reservoir in southern Heshui as the research object.The Xifeng Oilfield and Heshui Oilfield have been discovered near the research area with hundreds of millions of tons of geological oil reserves.The research area has great potential for exploitation,that’s because of the geological conditions in this area are similar to that in Xifeng Oilfield,and some exploratory wells implemented in the early stage have obtained good oil and gas display.However,the problems of rapid changes in the sand body plane and large differences in reservoir properties gradually come to the fore in the process of large-scale development,which makes it difficult to guarantee the development effect.In this study,a large amount of logging and core data were collected.On the basis of summarizing previous research results,the reservoir of chang8 formation was classified and evaluated from the aspects of formation correlation,sedimentary characterization and laboratory test,and the favorable development area was predicted.The main achievements are as follows:(1)In the southern part of Heshui,the delta front subfacies are developed in Chang 8reservoir,which is mainly controlled by the southwest sedimentary system of the basin.Then,the main sedimentary microfacies are the underwater distributary channel and the diversion bay.And the sand body of the esearch layer is distributed in the southwest-northeast direction under the control of the sedimentary background.(2)The study area of Change 8 reservoir belongs to the ultra-low permeability reservoir.The main rock types of this reservoir are feldspathic litharenite and lithic arkose;the main types of interstitial materials are iron calcite,chlorite,etc;the pore types are mainly residual intergranular pore.The porosity and permeability of the reservoir are reduced and its physical properties become worse,due to the high content of interstitial materials and destructive diagenesis such as cementation and metasomatism.(3)Make classification and assessment of the Chang 8 reservoir in the study area from reservoir physical properties,pore types,diagenesis,mercury intrusion parameters,etc.Reservoirs of type II and III are mainly developed in Chang 8 of the study area.Reservoirs of type I-c are locally developed at the confluence of rivers,where the sand body is thicker and the reservoir property is better.(4)The Chang 8 reservoir in the study area is a lithologic reservoir,because of the oil-water distribution of Chang 8 reservoir is mainly controlled by sand body size,reservoir physical properties and lateral phase transition.(5)The favorable area prediction is carried out combined with the trial oil test and mining situation of the previous wells on the basis of reservoir evaluation.Two advantageous reservoir areas of class I with 28.4km~2 of oil-bearing area;and three dvantageous reservoir areas of classⅢwith 11.6km~2 of oil-bearing area are preferred.