塔河油田奥陶系碳酸盐岩古岩溶塌陷体特征及成因

摘要

Fracture-caved reservoirs in Ordovician carbonate rocks are the main oil and gas reservoirs in Tahe oilfield and the collapse resulted from the subsidence of ancient cave systems is one of the important types of the late karst reformation.Using the data of core,conventional logging,imaging logging,seismic reflection configuration and production performance,the paper analyzes and studies the identification method and the genesis of the collapse in carbonate rocks,presents a set of identification methods applicable to the karst collapses of fracture-caved reservoirs and establishes the corresponding identification criteria for them.Based on the genetic analysis,the karst collapses in Tahe oilfield can be classified into 3 genetic types including fracture induced collapse,overlying stratun load collapse and late-stage hypergene karst collapse.The statistics of 122 collapses of the fracture-caved reservoirs in Tahe oilfield show that the late-stage hypergene karst collapse has the greatest potential for oil and gas development due to the developed fractures and caves within the reservoir.%奥陶系碳酸盐岩缝洞型储集体是塔河油田主要的含油气储集体,因古溶洞系统垮塌而形成的塌陷体是重要的岩溶改造类型之一.针对碳酸盐岩塌陷体识别方法不健全、成因认识不清的现状,运用岩心、常规测井、成像测井、地震反射结构和生产动态特征进行分析研究,提出一套适用于缝洞型油藏岩溶塌陷体的识别方法,并建立了相应的识别标准.通过对岩溶塌陷体成因分析,将塔河油田岩溶塌陷体划分为断裂诱导塌陷体、上覆地层负载塌陷体和后期表生岩溶塌陷体3种成因类型.通过对塔河油田缝洞型油藏122个塌陷体开发效果统计分析,认为后期表生岩溶塌陷体缝洞发育,最具油气开发潜力.