Analysis Of Interlayers In Fan Delta Front Reservoir

Fan delta sedimentary reservoir has always been a hot research,and it is a main task of many researchers and scholars.Fan delta front,close to the former sub-phase delta,can be used as the high-quality reservoir due to a large scale of deposits of sand-body and good physical properties,so it is considered as an important target for oil and gas exploration.However,the sedimentary process of fan delta is very complex,and interlayers are well developed,although reservoir scale is very large.In the course of development,the interlayers has a strong blocking effect for subsurface fluid flowing within the reservoir,which causes remaining oil enrichment and leads to severe water channeling.Therefore,we can produce remaining oil to enhance oil recovery by the geological basis of analyzing origin and development characteristics and spatial distribution rules of interlayers,and meticulously depicting it.Combined oilfield production situation of LN2 well area,T ? oil group were studied.The research horizon is belong to the fan delta front facies,the target layer interlayers is identified and characterized,based on outcrop,logging,core and production dynamic data,guiding by sedimentary facies model.The study shows that,T?oil group belongs to fan delta front,when sedimentary source is rich,and water power is strong,sand body is contiguously distributed in flakes,which is subdivided into 9 monolayers.In this area researchers find thoes types of sedimentary microfacies;submarine distributary channel and subsea natural barrier and underwater distributary interchannel also.Core analysis shows that,the water boy of each monolayer gradually became deeper from bottom to up,and hydrodynamic strength was from strong to weak,resulting in progressive reduce of the scale of submarine distributary channel and subsea natural barrier and the distribution scope,in contrast with the range of underwater distributary interchannel increasing.Submarine distributary channel,as main reservoir of the target bed,develops interlayers,which can be divided into 3 types,such as muddy interlayers,calcareous intercalation and petrophysical intercalation.Among them,muddy interlayers can be divided into mudstone between channels,interlayer mudstone and residual mudstone in layers.Interlayer mudstone is stably distributed in the region and easy to identify,so it is the remained two that is fine studied.They have large scale with length from 400 to 3520 meters,and width from 260 to 620 meters and thickness from 0.6 to 3.8 meters,and is mostly long strip shape.Calcareous intercalation is controlled by diagenetic heterogeneity,which is mainly distributed in the bottom of channel sand bodys and smaller scale with length from 490 to 2560 meters and width from 220 to 650 meters and thickness from 0.5 to 2.8 meters,and it is mostly lenticular or long strip.Petrophysical intercalation is distributed in the outer of subsea natural barrier,which has smaller scale with length from 500 to 2780 meters and width from 250 to 630 meters and thickness from 0.6 to 2.8 meters,and it is long strip shape.