The Study On Well Testing Method For Multi-stage Fractured Horizontal Wells In Tight Gas Reservoirs And Testing Software Development

Tight gas reservoir with low porosity and low permeability is unconventional gas reservoir.In recent years,because of the low permeability of tight gas reservoir,low natural production capacity and huge difficulty to development,the scholars pay more attention to the research of tight gas seepage rule,at same time,the multi-stage fractured horizontal well technology has widely been applied.The study on multi-stage fractured horizontal well rarely takes the fracture conductivity and non-Darcy effect into account.The object of this paper is to study tight gas reservoir and well test analysis.Using modern seepage theory,well test method,mathematics method,computer programming and other subject's knowledge.We established and solved well test model of fractured horizontal well in homogeneous infinite formation and dual-porosity reservoir.The software is accomplished according to the well test analysis method.By the analysis which describes the dynamic change of fractured horizontal well pressure in the tight gas reservoir,this paper provides theoretical guidance for the study of tight gas reservoir.The main works in this paper are as follows:(1)A single fracture horizontal well model in single medium is established considering the change of fracture conductivity and non-Darcy effect,using a semi analytical method to solve the mathematical model of numerical discrete fracture,drawing the bottom-hole pressure response curve.It provides a theoretical basis for the establishment of multi-stage fractured horizontal wells in tight gas reservoirs.(2)The single medium in tight gas reservoir mathematical flow capacity with multi-stage fracturing horizontal well model is established which considering the change of fracture conductivity,using a semi analytical method to solve the mathematical model of numerical discrete fracture,drawing the bottom-hole pressure response curve,dividing whole flow pattern into a few flow stages according to the characteristic curve,and the influence of wellbore storage coefficient,skin factor,fracture spacing,fracture number and dimensionless conductivity coefficient on the curves is analyzed.(3)The double porosity medium in tight gas reservoir mathematical flow capacity with multi-stage fracturing horizontal well model is established which includes Quasi steady state and unsteady flow through a double porosity medium,using a semi analytical method to solve the mathematical model of numerical discrete fracture,drawing the bottom-hole pressure response curve,dividing whole flow pattern into a few flow stages according to the characteristic curve,and the influence of elastic storage ratio,inter-porosity flow coefficient and dimensionless conductivity coefficient on the curves is analyzed.(4)Based on the couple of well test analysis method,the C#programming language is used under Visual Studio platform in Windows platform application development environment,and the multifunctional well test interpretation software is compiled.(5)Based on the model established in the software,the data of the real test well are fitted well,and the validity of the model is verified.