CAJ | 학술논문

致密砂岩油藏水驱渗流特征体现非线性渗流规律，存在启动压力梯度，且水驱过程中多孔介质会产生变形，岩石渗透率降低。通过电镜扫描试验研究致密砂岩纳米级微观孔隙特征，结合岩石颗粒分布特征，建立致密砂岩变形引起应力敏感理论模型，得到岩石介质变形系数，并与试验测试结果进行对比分析；建立考虑致密砂岩岩石变形影响的渗流数学模型，研究启动压力梯度及介质变形共同作用对油、水两相非线性渗流特征影响。算例结果表明，启动压力梯度与介质变形的耦合作用造成水驱渗流阻力增大，地层压降损失增大；介质变形系数越大，相同生产时间内原油采出程度越低，随着生产时间增加，地层压降损失幅度增大。
치밀사암유장수구삼류특정체현비선성삼류규률，존재계동압력제도，차수구과정중다공개질회산생변형，암석삼투솔강저。통과전경소묘시험연구치밀사암납미급미관공극특정，결합암석과립분포특정，건립치밀사암변형인기응력민감이론모형，득도암석개질변형계수，병여시험측시결과진행대비분석；건립고필치밀사암암석변형영향적삼류수학모형，연구계동압력제도급개질변형공동작용대유、수량상비선성삼류특정영향。산례결과표명，계동압력제도여개질변형적우합작용조성수구삼류조력증대，지층압강손실증대；개질변형계수월대，상동생산시간내원유채출정도월저，수착생산시간증가，지층압강손실폭도증대。
The process of water flooding met the law of non-Darcy flow and existed threshold pressure gradient in tight sandstone reservoirs. Porous medium would get deformed,and the permeability would decrease. The nanometer pore characteristics of tight sandstone through scanning electron microscope(SEM) experiment were researched. Based on the distribution of rock particles,a theory model which characterized stress sensitivity caused by medium deformation was established and medium deformation coefficient was derived. The comparison analysis of results between the theory model and experiment is performed. Moreover,a seepage mathematical model was established which took the deformation of tight sandstone into consideration. The coupling influences of the threshold pressure gradient and medium deformation on the oil-water two-phase nonlinear percolation feature are studied. The result shows that the flow resistance and formation pressure drawdown loss increase under the coupling effects of threshold pressure gradient and medium deformation. Moreover,with the increase of production duration,amplitude of pressure drawdown loss would increase.