川西地区雷顶不整合面岩溶缝洞型储层特征与分布

CHARACTERISTICS AND DISTRIBUTION OF KARST-VUGGY RESERVOIR OF LEIDING UNCONFORMITY SURFACE,WESTERN SICHUAN BASIN

钻井、录井、测井及地震等资料表明,川西地区雷顶岩溶储层岩性主要为粉—细晶白云岩、亮晶砂屑白云岩、藻屑砂屑白云岩等,孔隙类型以晶间溶孔、粒间溶孔、溶蚀扩大孔为主;优质储层发育主要受到碳酸盐岩白云岩化重结晶叠加早期暴露溶蚀和晚期深埋溶蚀作用的控制。岩溶储层地震相表现为复合相位,断续或连续分布,能量减弱,具有在高阻背景下的相对低阻特征。综合预测认为,川西雷顶不整合面岩溶缝洞型储层呈北东南西向展布,总体由东向西增厚,在川西探区文星—新场—马井—金马—鸭子河一带最厚,大于50 m,最大可达80 m。

It is illustrated from drilling,mud- logging,well-logging and seismic data that(1) Leiding karst- vuggy reservoir, western Sichuan Basin,is mainly composed of silty- fine dolomite,sparry and algal dolarenite;(2) its porous types include primarily intererystalline and intergranular dissolution pore,and dissolution- enlarged pore;and(3)its development is mostly affected by the recrystallization of dolomitization in carbonate,and the early exposure dissolution and late deep- burial dissolution.For this karst reservoir,its seismic facies appears a compound form of both discontinuous and continuous distribution with gradually weak energy;meanwhile,it is characterized by relatively low resistance against a high- resistance background.After a comprehensive evaluation,it is deemed that the karst- vuggy reservoir is distributed in a NE- SW trend,which its thickness increases roughly from east to west,especially the thickest occurring in Wenxing- Xinchang- Majing- Jinma- Yazihe area(the thickness more than 50 m,and the maximum reaching 80 m),