The maximum effective hole-diameter mathematical modei describing the flow of slightly compressible fluid through a commingled reservoir was solved rigorously with consideration of wellbore storage and different skin ...The maximum effective hole-diameter mathematical modei describing the flow of slightly compressible fluid through a commingled reservoir was solved rigorously with consideration of wellbore storage and different skin factors. The exact solutions for wellbore pressure and the production rate obtained from layer j for a well production at a constant rate from a radial drainage area with infinite and constant pressure and no flow outer boundary condition were expressed in terms of ordinary Bessel functions. These solutions were computed numerically by the Crump's numerical inversion method and the behavior of systems was studied as a function of various reservoir parameters. The modei was compared with the real wellbore radii modei. The new modei is numerically stable when the skin factor is positive and negative, but the real wellbore radii modei is numerically stable only when the skin factor is positive.展开更多
The pressure response for the composite reservoirs with a sealing fault locating in inner and outer region is different,which neglected by previous researchers,would cause significant errors during well-test interpret...The pressure response for the composite reservoirs with a sealing fault locating in inner and outer region is different,which neglected by previous researchers,would cause significant errors during well-test interpretations.Based on seepage theory,a well-test model of two-region radial composite reservoir with infinite outer boundary has been built in this study considering wellbore storage and skin effects.The solutions for this model and characteristics of the type curves have been analyzed by applying the method of mirror image,Laplace transformation and superposition principle,including a straight fault,a perpendicular fault and parallel faults cases.The study shows that the dimensionless pressure derivative curves would be obviously different in two cases:the well to fault distance is larger,and smaller than the half length of the inner-region radius.Therefore,type curves are presented with reasonable parameters to analyze the distance effect on the dynamic pressure response.The results in this study are of great significance。展开更多
A new model called semi-permeable wall model is presented for multilayer gas reservoir. The model is used to study the influence of crossflow on pressure transient well tests and other single-phase flow problems. It i...A new model called semi-permeable wall model is presented for multilayer gas reservoir. The model is used to study the influence of crossflow on pressure transient well tests and other single-phase flow problems. It is suggested here to use this model to approximate the actual multilayer gas reservoir, so that the problem is greatly simplified mathematically. Its differential equation is established here for multilayer gas reservoirs, and is linearized by normalized pseudo pressure and pseudo time. Simulation program is developed by finite-difference method when all layers are perforated. The feature of wellbore pressure and rate is clarified by analyzing the results of numerical simulation.展开更多
基金National Natural Science Foundation of China(No.50206016)Special Funds for Major State Basic Research Program of China(973 Program,No.1999022308)
文摘The maximum effective hole-diameter mathematical modei describing the flow of slightly compressible fluid through a commingled reservoir was solved rigorously with consideration of wellbore storage and different skin factors. The exact solutions for wellbore pressure and the production rate obtained from layer j for a well production at a constant rate from a radial drainage area with infinite and constant pressure and no flow outer boundary condition were expressed in terms of ordinary Bessel functions. These solutions were computed numerically by the Crump's numerical inversion method and the behavior of systems was studied as a function of various reservoir parameters. The modei was compared with the real wellbore radii modei. The new modei is numerically stable when the skin factor is positive and negative, but the real wellbore radii modei is numerically stable only when the skin factor is positive.
基金This work was financially supported by National Science and Technology Major Project no.2016ZX05015-003 and no.2017ZX05009-004.
文摘The pressure response for the composite reservoirs with a sealing fault locating in inner and outer region is different,which neglected by previous researchers,would cause significant errors during well-test interpretations.Based on seepage theory,a well-test model of two-region radial composite reservoir with infinite outer boundary has been built in this study considering wellbore storage and skin effects.The solutions for this model and characteristics of the type curves have been analyzed by applying the method of mirror image,Laplace transformation and superposition principle,including a straight fault,a perpendicular fault and parallel faults cases.The study shows that the dimensionless pressure derivative curves would be obviously different in two cases:the well to fault distance is larger,and smaller than the half length of the inner-region radius.Therefore,type curves are presented with reasonable parameters to analyze the distance effect on the dynamic pressure response.The results in this study are of great significance。
基金the National NatualScience Foundation of China (No.59995460).
文摘A new model called semi-permeable wall model is presented for multilayer gas reservoir. The model is used to study the influence of crossflow on pressure transient well tests and other single-phase flow problems. It is suggested here to use this model to approximate the actual multilayer gas reservoir, so that the problem is greatly simplified mathematically. Its differential equation is established here for multilayer gas reservoirs, and is linearized by normalized pseudo pressure and pseudo time. Simulation program is developed by finite-difference method when all layers are perforated. The feature of wellbore pressure and rate is clarified by analyzing the results of numerical simulation.
