受井眼轨迹控制的低渗气藏水平井积液预测模型及应用

发布时间：2018-08-30 08:10

【摘要】：气井积液将会造成气井产能大幅下降,需及时准确预测井筒积液量,实施对应有效排水采气措施,保护气井产能。在积液量预测研究中,以往学者主要采用气井短期生产过程中油套压下降幅度或者关井油套压差来计算积液高度,从而得出积液量,但是针对低渗气藏水平井长期生产状态下预测井筒积液量的问题现有方法显得无能为力。针对低渗气藏压裂水平井在开井生产状态下无法准确预测井筒积液量的问题,首先在单相低渗透气藏压裂水平井井筒、裂缝、气藏耦合流动的理论基础上,考虑气水两相流动,根据流体力学理论和动量定理,结合两相渗流理论及实际气体状态方程,建立新的低渗气藏压裂水平井气水两相渗管耦合模型；然后在此出发,提出利用油压作为约束,建立了由井筒持液率剖面预测井筒积液量的模型。针对不同井眼轨迹下的水平井积液预测模型,在水平型水平井积液预测模型的框架上,调整水平段井斜角,建立了上倾型、下倾型及起伏型水平井积液预测模型,同时完成了Fluent模拟研究及现场实例验证。研究结果表明了该预测模型在气井正常生产时就可准确计算积液量,而无需关井测试；且针对长时间生产条件下的气井,能及时判断其积液情况。在水平段井眼轨迹对积液影响的研究中发现小角度的上倾型水平井最不易积液。
[Abstract]:The gas well fluid accumulation will cause the gas well productivity to be greatly reduced. It is necessary to predict the wellbore fluid accumulation in time and accurately implement the corresponding effective drainage and gas production measures to protect the gas well productivity. In the research of fluid accumulation prediction, in the past scholars mainly used the drop range of oil casing pressure or the pressure difference of shut-in oil casing to calculate the liquid accumulation height in the short term production process of gas wells, thus obtaining the amount of fluid accumulation. However, there is no way to predict the wellbore fluid accumulation under the long-term production of horizontal wells in low permeability gas reservoirs. In order to solve the problem that it is impossible to accurately predict the wellbore fluid accumulation in a fractured horizontal well in a low permeability gas reservoir under the condition of open hole production, firstly, on the basis of the theory of coupling flow of fractured horizontal well, fracture and gas reservoir in single-phase and low permeability gas reservoir, the gas-water two-phase flow is considered. According to hydrodynamics theory and momentum theorem, combined with two-phase percolation theory and actual gas state equation, a new coupling model of gas-water two-phase seepage pipe in fractured horizontal wells in low permeability gas reservoir is established, and then the oil pressure is used as the constraint. A model for predicting wellbore fluid accumulation from wellbore liquid holdup profile is established. Aiming at the fluid accumulation prediction models of horizontal wells under different wellbore trajectory, on the frame of horizontal well fluid accumulation prediction model, the slope angle of horizontal section well is adjusted, and the updip, downdip and undulating horizontal well accumulative fluid prediction models are established. At the same time, the Fluent simulation research and field examples are completed. The results show that the prediction model can accurately calculate the amount of fluid accumulated in the normal production of gas wells without the need of well shut-down test, and can judge the accumulation of fluids in time for gas wells under the conditions of long time production. In the study of the influence of wellbore trajectory on fluid accumulation in horizontal section, it is found that small angle upward horizontal well is the most difficult to accumulate fluid.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE243

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