A Study Of The Percolation Mechanisms With Rock Deformation And The Application For Low Permeability Gas Reservoir

In these years, amount of gas fields with low porosity and permeability of our country are discovered, how to develop these kinds of fields are the very important things that must to be solved, and the key to develop these gas fields is the mechanism of fluid flow through the porous medium. So, according to the real situation of low permeability reservoirs in China, the percolation mechanisms for low permeability reservoir with irreducible water was studied deeply based on the lab results and theoretical investigation, in this paper, by combing rock mechanics with fluid flow mechanics, reservoir engineering and reservoir numerical simulation, considering non-Darcy flow, media deformation and the movement of irreducible water as the integer, breakthrough the research methods of separating all sorts of factors, then, the percolation mechanisms for low permeability reservoir with irreducible water was found out, and the corresponding mathematical model was set up solved. The SuLiGe gas field was researched as the example of applied research, to present the more scientific theory direction for developing the low permeability deformation gas reservoir with high efficiency. The first, the rock deformation experiment was designed for the low permeability deformation gas reservoir. On the basic of deformation experiment, the characteristics of the low permeability gas reservoir deformation were researched. The corresponding experiments presented the data of the porosity, permeability diversification with the confining pressure or the pore-pressure and the rock deformation instance with various irreducible water saturations. The second, the rock deformation mechanism, the influencing factor on deformation, the law of the low permeability gas reservoir rock, the law of irreducible water change with the rock deformation and the critical value of irreducible water were all analyzed. The corresponding mathematical model was set up. The third, the complete set of model on low permeability gas reservoir with irreducible water numerical simulation with the coupling of the fluids and reservoir deformation was set up, by the method of combining the plasto-elasticity and fluid mechanics in porous medium, for the first time, and the solution was researched. This is different from the bygone model which can not describe the gas reservoir definitely, for not considering the infection of irreducible water during the reservoir was developed. The last, the research findings were exercised in SuLiGe gas field practice research, such as the characteristic of permeability variation around gas well-bore, the distribution of permeability around gas well-bore, the mechanism of the abnormity for deliverability testing data, and so on. Many new realizations were gotten out, which is the basic of the science development of low permeability gas reservoir and the dynamic analysis.