Reservoir Architectural Characteristics And Remaining Oil Distribution In Wen 79 South Block In Zhongyuan Oilfield

Wen 79 South Block is located at the southern tip of Wen 79 Block in the Wenliu Structure,Dongpu Depression.The reservoir is relatively intact and the fracture is relatively undeveloped.At present,the degree of recovery in this area is relatively low,therefore,the potential of remaining oil adjustment is huge.The heterogeneity of reservoir architecture is complex and the reservoir changes greatly,resulting in difficulty of water breakthrough or rapid flooding,which makes the recovery efficiency of the study area lower.Therefore,this paper is expected to find out the heterogeneity of the reservoir and the differential flow of fluid through the anatomy of the internal architecture of the reservoir,and provide a reference for the remaining oil in the area.This thesis takes S₂L submember as the research object.On the basis of sedimentary knowledge,based on core observation and sedimentary simulation experiments,the sedimentary model in this area was constructed.Under the guidance of the model,the internal architectural anatomy of the reservoir was carried out by logging data and the internal architecture model was established.Then,based on reservoir physical characteristics,the differential flow mechanism of reservoirs is analyzed.The idea of"static analysis and prediction,dynamic test and verification"was adopted to identify the reservoir's dominant flow channel with dynamic development data.Finally,on the basis of the analysis of the internal architecture,the law of fluid difference flow and the flow channel,the remaining oil is summarized.The remaining oil enrichment area is predicted and the corresponding development measures are put forward.The main results obtained in this paper are as follows:1)The sedimentary deposits in the study area are shallow-water sediments,which are different from the deltas with a unified diversion system that generally use distributary channels as skeletons.Instead,they are a kind of superposition deposition model with a single body as the basic unit.According to the sand body contact relationship,the contact patterns,such as tight contact,partial contact and separation contact,can be distinguished.2)Based on the anatomy of the reservoir architecture,it is believed that there are three types of superimposing styles:isolated body,lateral body and vertical body.The fluid flow capacity of different architectural units is different.The main sandbody of lobe is the best,the lateral margin of lobe is the second and the thin sand is the worst.The development characteristics of different architectural units are different.There are three different flow patterns,namely hypertonic shielding,hypertonic buffering,and separation blocking.The formation of these three differential flow patterns mainly depends on the physical properties of the reservoir units and their mutual contact relationship.3)Based on the history of well history and production dynamic data,the corresponding relationship between injection and production is analyzed.In combination with the results of internal architecture analysis,the response relationship between oil and water wells is analyzed,and the dominant flow channel is identified.4)There are three types of remaining oil in the study area.The first one is the interlayer or plane remaining oil caused by hypertonic shielding.The second one is the interlayer remaining oil caused by low permeability buffer.The last one is the imperfect remaining oil caused by non-permeating barrier.The three major types should adopt the following measures to tap remaining oil respectively:combination of injection and plugging to improve the efficiency of injection and production,the enhanced water injection to distribute or modify reservoirs,drilling new wells or digging new holes to repair the oil sand body.This study provides technical support for the prediction of remaining oil in the study area and provides reference for other high water cut oilfields.