Meandering Well Seepage Law And Capacity Analysis

At present, the stage of complex reservoir development is coming in China. And our petroleum industry is confronted with severe technological challenges, so new technologies and theories should be investigated to develop these complex reservoirs. Among them, complex well technology and its development theory are significant to exploit complex reservoirs and should be focused on and studied. Snaky well is a new type of complex well that are used in oil-field development both in China and at abroad in recent years. And it has an extensive potential application in China. But there are not any reports of achievements in studying fluid flow laws through porous media and productivity analysis of snaky wells. So the chief work in this dissertation aims at studying seepage laws and productivity analysis of snaky wells. In this way, the accomplishments in this dissertation can provide theory reference for development plan design and analysis and prediction of production performance when snaky wells are used to develop oil-field. By adopting theories and methods such as reservoir engineering, hydromechanics, mathematical analysis and numerical simulation, the acquired achievements are as follows:1. On the basis of the established mechanical model of snaky well and compared with conventional horizontal well, the influences that well types of snaky well exert on well productivity and seepage laws are analyzed. Furthermore, it is demonstrated that vertical wave of snaky well has a large influence on its wellbore flow and inflow performance. Therefore, snaky well is a new type of complex well that is different from conventional horizontal well. And snaky well can not be simplified as horizontal well to study seepage laws and productivity analysis.2. On the basis of wellbore structure characteristics and variable-mass flow performance of snaky well, basic hydromechanics theory is used to establish wellbore pressure drop models of single-phase flow and two-phase stratified flow in snaky well with open hole completion or perforation completion. And calculation methods of wellbore pressure drop on operating conditions of fixed production rate or fixed bottomhole producing pressure are presented.3. By adopting analytic method, single-phase stable seepage laws of snaky well are studied and attained. Seepage mathematical models of single snaky well in several kinds of reservoir, such as infinite reservoir, bottom-water reservoir, gas-cap reservoir, reservoir with bottom water and gas cap, edge water reservoir and sealed reservoir, are established. Furthermore, according to basic theory of mechanics of fluids in porous media and mathematical analysis method, analytic solutions of these models are attained. And formation pressure distribution law of single snaky well with single-phase stable flow is attained, too.4. By adopting analytic method, single-phase unstable seepage laws of snaky well are studied and attained. Seepage mathematical models of single snaky well in several kinds of reservoir, such as sealed reservoir, gas-cap reservoir and reservoir with bottom water and gas cap, are established. Furthermore, according to basic theory of mechanics of fluids in porous media and mathematical analysis method, analytic solutions of these models are attained. And formation pressure distribution law ofsingle snaky well with single-phase unstable flow is attained, too.5. Using numerical simulation method and multisection well model, compared with horizontal well and vertical well, seepage features of single snaky well with multiphase flow is attained. And seepage features of single snaky well when adopting combined well pattern of snaky wells and vertical wells is attained, too. Moreover, numerical simulation method is adopted to study inflow performance characteristics of snaky well in solution gas drive reservoir. In this way, it is pointed out that traditional methods have limitations in plotting IPR curve of snaky well and an improved method is presented to realize it.6. By coupling wellbore flow and reservoir seepa...