致密砂岩油可动量及其主控因素——以鄂尔多斯盆地三叠系延长组长7为例  

Movable oil and its controlling factors in tight sandstones:A Case study of the Triassic Chang7 reservoir,Yanchang Formation,Ordos Basin

作　　者：崔景伟[1] 朱如凯[1] 李士祥[2] 杨智[1] 张忠义[2] 

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中国石油长庆油田公司勘探开发研究院,西安710018

出　　处：《石油实验地质》2016年第4期536-542,共7页Petroleum Geology & Experiment

基　　金：国家重点基础研究发展计划(973计划)项目"中国陆相致密油(页岩油)形成机理与富集规律"(2014CB239000);国家油气重大专项"岩性地层油气藏成藏规律;关键技术及目标评价项目"(2011ZX05001)资助

摘　　要：中国致密油地质储量超过100×108 t，但确定可采资源量难度较大。通过改进耗散型石英微天平分析仪（QCM－D）实现地层条件下岩心的单位原油吸附量、利用高压压汞和N2吸附手段对含油孔隙下限和有效比表面积测试，最后结合密闭取心含油量测试结果，对鄂尔多斯盆地三叠系延长组长7油层组可动油开展评价。结果显示长7致密砂岩表面吸附油厚度15．6 nm，吸附质量13 mg／m2；含油孔径下限为18 nm左右，比表面积平均为1 m2／g；孔隙度6％～10％，游离态原油比例为14．3％～48．6％，结论与核磁共振实验测定结果具有可比性。控制致密砂岩原油可动量的地质因素包括原油密度、黏度、有效孔隙表面积、有效孔隙体积以及储层矿物组成，针对特定区域和层系，可动量主要受孔比表面积控制。Tight oil in place in China has been estimated over 10 billion tons, but it is difficult to define the availably producible reserves. Several efficient ways, including perfecting Quartz Crystal Microbalance with Dissipation （ QCM-D） to evaluate adsorption ratio per unit in subsurface cores, applying mercury injection capillary pressure （ MICP） and nitrogen adsorption to define the lower oily limit and the effective specific surface area, and combi-ning oil testing results in confined cores, were utilized to evaluate the movable oil in the Triassic Chang7 reser-voir, Yanchang Formation, Ordos Basin. The results indicated that the thickness of oil adsorbed on tight sand-stone surfaces was 15. 6 nm with an intensity around 13 mg/m2 , the lowest oily limit was around 18 nm, the effective specific surface area was around 1m2/g, the porosity was around 6%-10%, and the ratio of free oil was around 14.3%-48.6%. All these results were comparable with the NMR experiments. Several factors controlled the movable oil amounts in tight sandstones, including crude oil density and viscosity, effective specific surface area, effective porosity volume and mineral constituents. For specific region or layer, the amounts of movable oil is parametrically controlled by pore surface area/effective porosity volume.

关 键 词：吸附态 游离态 致密油 延长组 鄂尔多斯盆地 

分 类 号：TE122[石油与天然气工程—油气勘探]