松辽盆地南部长岭断陷登娄库组致密砂岩有利储层控制因素

应用普通薄片、铸体薄片、扫描电镜、物性分析及粘土矿物衍射,对松辽盆地南部长岭断陷登娄库组致密砂岩储层基本特征进行分析。结合区域构造特征、沉积特征及成岩作用研究该套致密砂岩的成因,分析致密砂岩中优质储层发育的控制因素。研究结果表明:登娄库组储层为一套辫状河及辫状河三角洲沉积砂体,岩石类型主要是岩屑质长石砂岩或长石质岩屑砂岩。现今洼陷内储层均已致密,沉积作用是形成致密储层的最基本因素,物源区岩性决定后期成岩作用的类型和强度,成岩作用中压实作用、胶结作用则是形成致密储层的关键。致密砂岩中优质储层受多种因素的控制作用,储层沉积相、砂岩粒径及深部流体溶蚀是控制登娄库组优质储层分布的主要因素。

Controlling factors on high quality reservoir of tight sandstone of Denglouku Formation in Changling Fault Sag,southern part of Songliao Basin

The characteristics of tight sandstone reservoirs of the Denglouku Formation in the Changling Fault Sag were investigated,based on measurements normal thin-sections,cast thin-sections and cathodoluminescence thin-sections,scanning electron microscope,and X-ray diffraction of clay minerals.The reason of tight sandstone reservoirs and the controlling factors of high quality reservoir dealt with tentonic characteristics,combining sedimentary characteristics and diagenesis were analyzed.The results show that the reservoir of Denglouku Formation is a set of braided river and braided river deltaic sediments,which is comprised of feldspathic litharenitc and lithic arkose.The reservoirs in fault subsidence have all become densified.Sedimentation is the most fundamental element to form tight sandstone.The type and intensity of diagenesis are decided by lithologic character of parent rock.The compaction and cementation are the key points to form tight sandstone.The formation of high quality reservoir is controlled by a lot of elements.Sedimentary facies,particle diameter of sandstone and deep fluid dissolution are the main elements to control the distribution of high quality reservoir.