辽河盆地东部凸起太原组页岩气聚集条件及有利区预测

Shale gas accumulation factors and prediction of favorable area of Taiyuan Formation in Liaohe Eastern Uplift

从辽河盆地东部凸起太原组泥页岩发育的沉积背景、地球化学条件、储集物性及含气性等方面分析页岩气聚集的基础条件,采用多信息叠合法对该区太原组页岩气富集有利区进行预测.结果表明:太原组地层发育潮坪、沼泽及泻湖相,富有机质暗色泥页岩、碳质泥页岩,单层厚度大,分布面积广,连续性好,有机碳平均质量分数为3.3%,有机质类型以Ⅲ型为主的混合型,生烃潜力较大,热演化程度高,处于大量生气的阶段;泥页岩脆性较好,孔隙和裂缝发育,含气性好,具备页岩气聚集的地质、地球化学条件及储集物性条件,有利于页岩气的生成、富集及后期储层改造.根据页岩气富集的多种因素分析结果,认为王家南部地区页岩气聚集条件和储集性能较优越,是辽河盆地东部凸起太原组页岩气勘探开发的有利区域.

The basic conditions of shale gas accumulation was analyzed by study of depositional background,geochemical conditions,reservoir properties and gas-bearing of Taiyuan Formation on Liaohe Eastern Uplift,and favorable shale gas-rich zone in of Taiyuan Formation was predicted by the method of multiple factors superposition.This study shows that marshes,tidal flat and lagoons facies with dark organic-rich shale,carbonaceous shale developed well in Taiyuan formation of Liaohe Eastern Uplift.These shales possess good factors,such as large individual layer thickness,wide distribution,good continuity,whose organic carbon content reaches 3.3%,organic matter type is mainly III,which has excellent hydrocarbon generation potential and high degree of thermal evolution,at the stage of massive gas generation.Meanwhile,the dark shale owns good brittleness and good developments of pores and fractures in addition to high gas content,so the shales of Taiyuan Formation possess good geological,geochemical conditions and reservoir property conditions for gas accumulation,which helps shale gas generation,accumulation and late reconstruction of the reservoirs.Comprehensive analysis of the factors of shale gas enrichment suggests that the southern area of Wangjia possesses the most valuable conditions for shale gas accumulation,which,therefore,serves as the central favorable area of the breakthrough of shale gas exploration in Liaohe Eastern Uplift.