| In recent years,the problem of casing damage in the Sazhong Development Zone has been grim.According to statistics,the main types of casing damage are mainly deformation and dislocation,accounting for 94.77% of the type of casing damage,which will seriously restrict the area from achieving good economic benefits and an efficient development process.Therefore,this article takes the typical well group in Sazhong Development Zone as the research object,establishes a three-dimensional fluid-structure coupled seepage model,explores the relevant laws of the main development parameters and the risk of casing damage,and on this basis combines the actual conditions of the development zone in Sazhong to define the main development.The parameter's optimization threshold.Based on the mathematical model of fluid-structure interaction theory,this paper establishes a three-dimensional 1 injection and 1 mining concept model.Using injection pressure and production pressure as variables,it explores the risk mechanism of formation instability caused by fluid-structure interaction in the development of oil fields.And made a preliminary assessment of the rationality of the model program.Based on this,combined with the actual mining area in Sazhong Development Zone,a three-dimensional and five-point model was further established to study the pressure maintenance level,injection bottom hole pressure,production bottom hole flow pressure,oil production rate,and injection and production ratio.The main development parameters of the development of production and well network integrit y and its impact on the risk of casing damage,based on the first three major development parameters,designed a constant pressure program model;Based on the latter two main development parameters,a quantitative solution model was designed.Through The 3D Coulomb Criterion,the geotechnical simulation and analysis of the injection and mining system at Sazhong Development and Mining Area was conducted to obtain the results of the risk level of different strata and the average risk of the risk result was obtained.The three attributes of value,risk point-to-point ratio and maximum risk value are programmed and processed automatically.The risk data in each solution model is extracted,and risk sensitivity identification is performed according to three data processing methods: normalization,PCA,and MIN-MAX.Sensitivity analysis initially defines and optimizes the main development parameters.Based on this,a corresponding risk function curve was established.Through the extreme value processing of the risk function,the risk extreme function formula was obtained,and then a practical risk prediction map of the main development parameters in the Sazhong Development Zone was established.Through the combination of the risk data of the Casing Damage Database of the Sazhong Development Zone and the lithologic distribution characteristics of the actual casing damage point of the Sazhong Reservoir,a reasonable water drive with the lowest risk of casing damage that meets the actual production conditions in the Sazhong Development Zone is finally given.The main development parameters of the threshold: the production well bottom flow pressure in the 4MPa ~ 6MPa,pressure maintenance level in the 80% to 90%,within the scope of the production operation system allowed,the injection well bottomhole pressure should choose the lower value is excellent.With an oil recovery rate of 0.6% and an injection-production ratio of 0.9-1.05,the risk of casing damage is minimal.This will provide certain reference for Sa in the prevention of casing damage in the future and the safe and efficient production of reasonable development threshold adjustment of water drive development. |
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