玛湖凹陷西斜坡百口泉组砂砾岩储集层特征及物性控制因素

Characteristics of Sandy Conglomerate Reservoirs and Controlling Factors on Physical Properties of Baikouquan Formation in the Western Slope of Mahu Sag, Junggar Basin

准噶尔盆地玛湖凹陷西斜坡百口泉组为扇三角洲砂砾岩沉积,火成岩岩屑含量高,储集层之间物性差异大,一直以来制约油气勘探。综合运用岩心观察、薄片鉴定等对百口泉组储集层特征及其控制因素进行研究,对玛湖凹陷西斜坡百口泉组砂砾岩储集层进行了重新分类及命名,结合研究区岩心粒度分布特征,在GB/T 17412.2—1998《岩石分类和命名方案沉积岩岩石分类和命名方案》的基础上,将中砾岩进一步划分为小中砾岩及大中砾岩,在此基础上明确了研究区砂砾岩粒度适中、黏土矿物含量较低及次生溶蚀发育是形成优质储集层的关键。

Baikouquan formation in the western slope of Mahu sag, Junggar basin is a set of fan-delta sandy conglomerate depositions. Highcontent of igneous rock debris and the big differences among physical properties of reservoir sections always constrain the petroleum explo-ration in the area. The reservoir characteristics of Baikouquan formation and the controlling factors are studied based on core observationand thin section identification, and the sandy conglomerate reservoirs of Baikouquan formation in the western slope of Mahu sag are re-clas-sified and denominated. Combined with the grain size distribution of cores in the study area and based on the standard GB/T 17412.2—1998 Rock Classification and Naming Scheme： Sedimentary Rock Classification and Naming Scheme, pebble conglomerate is further divid-ed into fine pebble conglomerate and coarse pebble conglomerate. Based on which, moderate grain size of sandy conglomerate, relativelylow content of clay minerals and secondary corrosion are considered as the key factors for high-quality reservoir formation.