湖相混积型页岩油储层孔隙度计算方法

Porosity Calculation Method of Lacustrine Mixed Shale Oil Reservoir

湖相混积型页岩油储层岩性复杂,黏土含量高,黏土矿物类型多样且含量变化大,难以选择骨架参数及准确计算孔隙度。应用岩石物性分析、全岩X衍射分析,结合含泥岩石物理体积模型,求取黏土矿物骨架值;利用常规测井资料及能谱测井资料,建立黏土骨架计算模型;基于元素测井计算矿物类型及含量,结合黏土骨架计算模型,建立变黏土骨架孔隙度计算模型,进一步求取混积型页岩油储层孔隙度。与常规拟合法和变骨架孔隙度计算方法相比,变黏土骨架孔隙度计算模型精度较高,解决了湖相混积型页岩油储层孔隙度计算难题,易于在此类储层推广应用。

Lacustrine mixed shale oil reservoir is characterized by complex lithology,high clay content,multiple clay mineral types and large variation of clay content.It is difficult to select skeleton parameters and calculate porosity accurately.In this paper,the skeleton values of clay minerals are obtained by means of petrophysical property analysis,whole-rock X-ray diffraction analysis and physical volume model of mud-bearing rocks.Using conventional logging data and energy spectrum logging data,the clay skeleton calculation model is established.Based on the calculation of mineral types and content by elemental logging,combining with the calculation model of clay skeleton,a calculation model of variable clay skeleton porosity is established to calculate the porosity of mixed shale oil reservoir.Compared with the conventional fitting and variable skeleton porosity calculation methods,the variable clay skeleton porosity calculation model has relatively higher accuracy,which solves the problem of porosity calculation of lacustrine miscible shale oil reservoirs,and is easy to be popularized and applied in lacustrine mixed shale oil reservoir.