CAJ | 학술논문

常规液相钻井技术对油气藏储层污染空间分布特征的认识是许多学者关心问题。采用高能、高精度CT仪探索研究了钻井液污染后全直径岩心3D空间分布特征，建立了相应测试方法及定量判断钻井液滤失深度手段，获取了不同条件下钻井液污染三维空间分布图形；并结合电镜扫描及能谱分析，分析孔隙型及裂缝型储层钻井液污染微观特征。研究表明，钻井液滤失深度主要集中在离岩心端面11~24 mm；钻井液污染后孔隙型、裂缝型储层岩心污染空间呈“锅底状”特征，裂缝型储层岩心还可观察到钻井液贯穿整个裂缝；压差及裂缝导流能力是制约钻井液侵入基质孔隙深度的重要因素；裂缝中侵入颗粒以重晶石颗粒、盐类结晶为主，以区域性滤饼、团聚状颗粒形态分布；基质孔隙储层侵入颗粒以盐类结晶为主，以孔隙表面沉淀、孔隙充填、孔喉堵塞分布。研究成果为深入认识孔隙型、裂缝型储层钻井液污染特征提供重要机理认识，为室内实验评价技术提供了新的研究技术方法。
상규액상찬정기술대유기장저층오염공간분포특정적인식시허다학자관심문제。채용고능、고정도CT의탐색연구료찬정액오염후전직경암심3D공간분포특정，건립료상응측시방법급정량판단찬정액려실심도수단，획취료불동조건하찬정액오염삼유공간분포도형；병결합전경소묘급능보분석，분석공극형급렬봉형저층찬정액오염미관특정。연구표명，찬정액려실심도주요집중재리암심단면11~24 mm；찬정액오염후공극형、렬봉형저층암심오염공간정“과저상”특정，렬봉형저층암심환가관찰도찬정액관천정개렬봉；압차급렬봉도류능력시제약찬정액침입기질공극심도적중요인소；렬봉중침입과립이중정석과립、염류결정위주，이구역성려병、단취상과립형태분포；기질공극저층침입과립이염류결정위주，이공극표면침정、공극충전、공후도새분포。연구성과위심입인식공극형、렬봉형저층찬정액오염특정제공중요궤리인식，위실내실험평개기술제공료신적연구기술방법。
The understanding on spatial distribution features of oil/gas reservoir pollution by conventional liquid drilling technique is a concern of many scholars. The authors used high-energy, high-precision CT instrument to explore the 3D spatial distribution features of full-diameter core after being polluted by drilling lfuid, established the corresponding test method and the means of quantitatively determined the ifltration depth of drilling lfuid, and obtained the 3D spatial distribution diagram of drilling lfuid pollution under various conditions. Besides, the authors analyzed the microscopic features of porous and fractured reservoir drilling lfuid pollution with the help of scanning electron microscope and energy spectrum. The research shows that the drilling lfuid ifltration depth mainly occurs at 11 mm to 24 mm from the core end face. After being polluted by drilling lfuid, the core from porous and fractured reservoirs shows‘pot-bottom’ feature of polluted space. And from fractured reservoir cores, it can be observed that drilling lfuid has penetrated the whole fracture. Pressure difference and fracture conductivity are the main factors restricting drilling lfuid from invading the matrix pore depth. The introduced particles in fractures are mainly barite grains and salt crystals and distributed in regional iflter cake and aggregated grains. The introduced particles in matrix porous reservoirs are mainly salt crystals and distributed in the forms of settlement on pore faces, pore iflling and throat plugging. The research ifndings provide an essential understanding on the mechanism of drilling lfuid pollution features in porous and fractured reservoirs and provide a new research method for indoor experimental evaluation.