Research on Optimal Design of Horizontal Well Development in Fracture-Cavity Carbonate Gas Reservoirs with Bottom Water

Abstract

AbstractFracture-vuggy carbonate gas reservoirs with bottom water have complex and multi-scale pore structures. The development and distribution of fractures and karst caves have extremely strong randomness and heterogeneity, as well as the complex gas-water relationship, these characteristics have severely restricted the scale of the benefit development of this type of gas reservoirs. In order to solve the above problems and maximize the benefits of gas reservoir development, in this paper a numerical simulation method for the development of fractured-vuggy carbonate gas reservoirs with bottom water considering the effect of friction was established by integrating a variety of technical means. This method takes into account factors such as the different production allocation, water avoidance height, width of the high-permeability fracture-cavity zone, location of fracture development zone, permeability of high-permeability zone, degree of fracture development and other factors, and the influence of working system, well layout method and reservoir physical properties on the effect of horizontal well development of bottom water gas reservoirs were comprehensively analyzed. The optimal value of the dimensionless water avoidance height of the horizontal section is determined to be around 0.4 through the optimization of relevant technical indicators. Moreover, the horizontal section should avoid large vertical fractures, and the heel end of the horizontal well should be far away from the fracture development zone. The research results have important guiding significance for the scientific and efficient development of fractured-vuggy carbonate gas reservoirs with bottom water.KeywordsFracture-cavity typeGas reservoir with bottom waterHorizontal wellCarbonate rockOptimized design