渤南油田义65区块开发后期沉积相再认识

渤南油田义65块为开发了30多年的低渗透油藏，主力油层为沙河街组三段9砂组。在开发后期，利用岩心、地质和丰富的测井、开发资料，对沉积特征及沉积微相的展布进行再认识，确认其为浊积扇沉积，按沉积特征可进一步划分出内扇、中扇和外扇3个亚相及若干微相。并对各亚相、微相特征进行了描述，分小层绘制了沉积微相平面分布图。中扇亚相是义65块浊积扇体的主体部分，根据沉积特征可细分为辫状水道微相、辫状水道间微相、辫状水道侧缘微相、朵状体微相。中扇辫状水道微相和朵状体微相储层最为发育。平面上，各小层以辫状水道为中心，向外依次发育水道间、辫状水道侧缘和扇缘沉积微相，在部分辫状水道末端发育朵状体，水道展布方向为南-北向或东南-西北向。

New understanding of sedimentary facies of Es3(9) in Yi 65 Block of Bonan oilfield at later stage of production

The major pay zone of Yi 65 block in Bonan Oilfield,a low permeability reservoir in production over 30 years,is the 9^th sand unit of the 3^rd Member of Shahejie Formation(Es³⁽⁹⁾).Nowadays,Yi65 block is at the later production stage.Based on the core,geologic,well logging and production data,we restudied the sedimentary features and microfacies of the major pay zone in the study area.The results show that it is turbidite fan deposit,and can be further divided into three subfacies(inner fan,mid-fan and outer fan)and several microfacies.We described the subfacies and microfacies and mapped the distribution of the sedimentary microfacies of each sublayer.The mid-fan is the main part of the turbidite fan in the study area,and can be further divided into braided channel,inter-braided channel,lateral wing of braided channel and lobes.Reservoirs of the braided channel and lobes are best developed.On plane view,the braided channel occurs in the central part,with the inter-braided channel,lateral wing of braided channel and lower fan occurring successively outwards.The lobes occur at the end of some braided channel.And the briaded channels are of SN-trending or SE-NW-trending.