高黏土陆相页岩实验技术及其应用

Experimental techniques and their application for high clay content continental shale

页岩储层“四性”实验评价是页岩油勘探开发的重要基础及核心。现有实验技术存在页岩含油量检测不准、微纳米孔隙测量视域小及代表性差、流动性直接测量参数缺乏等难题,不适应古龙页岩油生产需求。通过研发实验装备、确定实验条件,建立基于保压密闭岩心“四性”实验技术及流程。结果表明:古龙高成熟和成熟页岩含油量测定较国标法可减少损失71%和50%,应用新建不同成熟度页岩含油量恢复模型,恢复了国标法现场录井页岩含油量数据;高成熟与低成熟阶段页岩中干酪根有机质、不同赋存状态油和水定量特征差别明显,受干酪根有机质向页岩油转化及演化程度的控制;页岩孔缝组合构成规模储集空间及流动网络通道,储集空间分为2大类7亚类12种类型,总孔隙度高于粉砂质岩、灰质岩、云质岩;确定页岩油上部、中部、下部油层组含油性与流动性特征,圆柱状页岩样品驱替油率为16%~43%,同一地层温度(100℃)不同驱替压力(10~50 MPa)下的超临界CO_(2)驱替使孔隙度增加4.51百分点、渗透率增加0.53×10^(-3)μm^(2)。研究成果为页岩油规模增储和效益上产提供了实验依据。

Experimental evaluation of“4 properties”of shale reservoir is important foundation and core of shale oil exploration and development.Existing experimental techniques face challenges of inaccurate measurement of shale oil content,small visual field and poor representativeness of micro-nano pores measurement,and lack of direct parameters for fluidity measurement,which cannot meet the requirements for Gulong shale oil production.Through research and development of experimental equipment and determination of experimental conditions,“4 properties”experimental technique and its process are established based on pressure-maintainance sealed cores.The results show that measured oil content losses of highly mature and mature Gulong shale oil are respectively 71%and 50%lower than that measured by national standard method.New established restoration model for oil content of shale with different maturity is applied to restore shale oil content data from method of national standard on-site mud logging.Quantitative characteristics of kerogen organic matter,oil and water with different occurrence states of shale in high-maturity and low-maturity stages are significantly different,being controlled by transformation and evolution degree of kerogen organic matter to shale oil.Pores-fractures combination of shale constitutes large-scale accumulation space and flow paths network.Reservoir space is divided into 2 classes of matrix pores and fractures,including 7 subclasses and 12 types,with total porosity higher than that of siltstone,limestone and dolomite.Oil-bearing property and fluidity characteristics of upper,middle and lower shale oil reservoirs are determined,and oil displacement rate of cylindrical shale samples is 16%~43%.Supercritical CO_(2) displacement at same formation temperature(100℃)and different displacement pressures(10~50 MPa)increases porosity by 4.51%and permeability by 0.53×10^(-3)μm^(2).The research provides experimental evidence for large-scale reserves increase and beneficial production increase of shale oil.