四川盆地磨溪地区灯四段风化壳岩溶储层特征

近年来，四川盆地磨溪地区灯四段的油气勘探取得了重大突破，为研究磨溪22井区灯四上亚段优质岩溶储层特征及分布规律，开展了岩心分析、物性测试、地震资料解释、测井分析和有利岩溶储层发育区预测等工作。结果表明：①岩溶储层的岩性主要为藻云岩类、砂屑云岩类和结晶云岩类，储集空间主要为溶蚀孔、溶洞和裂缝；②溶蚀作用包括同生期大气淡水的溶蚀作用、埋藏期深部热液溶蚀作用和有机酸的溶蚀作用、表生期大气淡水的溶蚀作用；③表生期的溶蚀作用控制了优质储层的分布，多发育于垂直渗流带附近和水平潜流带上部区域，平面上优质储层的分布受控于沉积相带和古地貌特征，以丘滩相和溶丘斜坡较好。该研究成果为磨溪地区下一步勘探指明了方向。

Characteristics of weathering crust karst reservoir of Deng 4 member in Moxi area,Sichuan Basin

In recent years,great breakthroughs have been made in oil and gas exploration of Deng 4 member in Moxi area,Sichuan Basin.In order to study the characteristics and distribution regularity of high-quality karst reservoirs in the upper sub-member of Deng 4 member in Moxi 22 well area,core analysis,physical property testing,seismic data interpretation,logging data analysis and prediction of favorable development area of karst reservoir were carried out.The results show that:(1)The lithology of karst reservoir is mainly algal dolomite,sand-clastic dolomite and crystalline dolomite,and the reservoir space is mainly dissolved pore,cave and fracture.(2)The dissolution of carbonate rock includes the contemporaneous dissolution of atmospheric fresh water,deep hydrothermal dissolution and organic acid dissolution in the burial period,and dissolution of atmospheric fresh water in the supergene period.(3)The supergene dissolution controls the distribution of high-quality reservoirs which are mostly developed near the vertical vadose zone and the upper part of horizontal phreatic zone.The distribution of high-quality reservoirs in plane is controlled by sedimentary facies belt and palaeogeomorphological characteristics,with mound-beach facies and karst dome being the best.The research results indicate the direction for the next exploration in Moxi area.