CAJ | 학술논문

针对深部地层同一种泥岩，先后采用常规渗透测试、变围压渗透测试和三轴压缩下瞬态法3种方法开展渗透率的测试研究。试验发现，3种方法下泥岩的渗透率差别极大，其中常规渗透测试所得的渗透率高出后两种方法3~5个数量级；变围压法在围压大于5 MPa 后与三轴压缩下的瞬态法所测得的渗透率值较为接近；瞬态法下泥岩渗透率随偏应力增加而缓慢降低，偏应力高达30 MPa 时仍未出现扩容现象。测试显示泥岩的渗透率具有强烈的压力敏感性，其内在原因是较高围压下裂隙闭合、孔隙压紧、孔喉连通性减小，进而导致渗透率下降，而制样、烘干处理等对渗透率也有一定影响。基于试验结果与泥岩所处实际地层应力状态，提出可采用变围压法开展油气储集层的盖层的渗透率及其演化规律研究，而三轴压缩下瞬态法则更适用于能源储库盖层及核废料处置室围岩的渗透规律研究；常规渗透方法所得数据的应用则须商榷。研究结论对研究深部泥岩的渗透特性和密封性能有一定参考价值。
침대심부지층동일충니암，선후채용상규삼투측시、변위압삼투측시화삼축압축하순태법3충방법개전삼투솔적측시연구。시험발현，3충방법하니암적삼투솔차별겁대，기중상규삼투측시소득적삼투솔고출후량충방법3~5개수량급；변위압법재위압대우5 MPa 후여삼축압축하적순태법소측득적삼투솔치교위접근；순태법하니암삼투솔수편응력증가이완만강저，편응력고체30 MPa 시잉미출현확용현상。측시현시니암적삼투솔구유강렬적압력민감성，기내재원인시교고위압하렬극폐합、공극압긴、공후련통성감소，진이도치삼투솔하강，이제양、홍간처리등대삼투솔야유일정영향。기우시험결과여니암소처실제지층응력상태，제출가채용변위압법개전유기저집층적개층적삼투솔급기연화규률연구，이삼축압축하순태법칙경괄용우능원저고개층급핵폐료처치실위암적삼투규률연구；상규삼투방법소득수거적응용칙수상각。연구결론대연구심부니암적삼투특성화밀봉성능유일정삼고개치。
For the same deep mudstone, three testing methods of permeability (conventional testing method, variable confining pressure method, and pulse method under triaxial compression) have been conducted respectively. According to the testing results, large difference of permeability was found inbetween the three methods, in which the permeability of conventional method is 3-5 orders higher than those of the other two methods. The results of variable confining pressures method while its confining pressure exceeds about 5 MPa approach relatively the results of pulse method under triaxial compression. Permeability of pulse method slowly decreased with the increasing of deviatoric pressure, and dilatancy didn’t occur even when confining pressure reached 30 MPa. The results indicate that the permeability of mudstone is strongly sensitive to pressure; the intrinsic reason of which is that the cracks, fissures and pores in rock matrix tend to be compacted under high compression, which results in the reduction of pore size and connectivity for percolation channels and then causes the permeability to decrease; moreover, samples production, oven drying treatment, etc. also influence some of the permeability. Based on the results and the in-situ stresses conditions of mudstone, it is proposed that the variable confining method is suitable for the permeability and its development of reservoirs’ cap rock, while the results of pulse method under triaxial compression is more suitable for the cap rock of energy storage caverns and rock wall of wastes disposals. However, one should be very cautious while uses the results from conventional method. The research carried out supplies some constructive references for the analysis of the percolation properties and sealability of mudstone in deep strata.