CAJ | 학술논문

通过分析致密油充注孔喉下限与流体力学作用的相互关系，结合油气充注满足的力学条件，对源储界面和储集层内部的致密油充注孔喉下限进行理论探讨和实例分析。基于充注力学平衡关系及Young-Laplace方程，根据源储界面附近和储集层内部的最大充注动力建立相应的充注孔喉下限理论模型。将该模型应用于鄂尔多斯盆地延长组、四川盆地中下侏罗统、美国威利斯顿盆地Bakken组致密油，确定其源储界面附近的充注孔喉下限分别为15.74 nm、29.06 nm和14.22 nm，储集层内部充注孔喉下限分别为39.45 nm、37.20 nm和52.32 nm；相应的源储界面渗透率下限分别为0.0021×10-3μm2、0.0061×10-3μm2和0.0018×10-3μm2，储集层内部渗透率下限分别为0.0100×10-3μm2、0.0094×10-3μm2和0.0169×10-3μm2。源储界面岩性复杂，孔隙度与渗透率相关性差；储集层内部岩性单一，孔隙度与渗透率相关性较明显，由此确定储集层内部相应的孔隙度下限为2.16%、2.00%和3.50%。图4表2参32
통과분석치밀유충주공후하한여류체역학작용적상호관계，결합유기충주만족적역학조건，대원저계면화저집층내부적치밀유충주공후하한진행이론탐토화실례분석。기우충주역학평형관계급Young-Laplace방정，근거원저계면부근화저집층내부적최대충주동력건립상응적충주공후하한이론모형。장해모형응용우악이다사분지연장조、사천분지중하주라통、미국위리사돈분지Bakken조치밀유，학정기원저계면부근적충주공후하한분별위15.74 nm、29.06 nm화14.22 nm，저집층내부충주공후하한분별위39.45 nm、37.20 nm화52.32 nm；상응적원저계면삼투솔하한분별위0.0021×10-3μm2、0.0061×10-3μm2화0.0018×10-3μm2，저집층내부삼투솔하한분별위0.0100×10-3μm2、0.0094×10-3μm2화0.0169×10-3μm2。원저계면암성복잡，공극도여삼투솔상관성차；저집층내부암성단일，공극도여삼투솔상관성교명현，유차학정저집층내부상응적공극도하한위2.16%、2.00%화3.50%。도4표2삼32
By analyzing the relationship between throat threshold and fluid forces of oil charge in tight reservoirs and according to the oil-charging mechanical conditions, the lower limits of throat at the interface between source and reservoir rocks and in the middle of reservoirs were determined theoretically. On the basis of Young-Laplace formula and the equilibrium between driving forces and capillary resistance, the threshold models were set up by using the maximum driving forces near the source-and-reservoir interface and inside reservoirs respectively. They were applied to the Yanchang Formation in the Ordos Basin, the middle-lower Jurassic in the Sichuan Basin and the Bakken Formation in the Williston Basin in America. The corresponding results near the interface are 15.74 nm, 29.06 nm, and 14.22 nm, and the ones in the middle of reservoirs are 39.45 nm, 37.20 nm, and 52.32 nm respectively. Accordingly, the threshold permeabilities of the three typical tight oil reservoirs calculated are 0.002 1×10-3 μm2, 0.006 1×10-3 μm2, 0.001 8×10-3μm2 near the interface and 0.010 0×10-3μm2, 0.009 4×10-3μm2, 0.016 9×10-3μm2 at the inner reservoirs. The rocks near the interface are complex, so there is a poor correlation between porosity and permeability, while inside reservoirs, homogeneous lithology results in good correlation between porosity and permeability. The porosity thresholds were determined as 2.16%, 2.00% and 3.50%respectively.