Calculating waterbody parameters in gas reservoirs based on intelligent algorithms
Reasonable determination of waterbody parameters in gas reservoirs is not only important to calculate water invasion pre-cisely but a great support for dynamic analysis of water-invaded reservoirs and adjustment of development plan.So,based on the ma-terial balance equation of water drive gas reservoirs,the model of waterbody parameters was developed to form an objective function,and these parameters were calculated under the premise of minimum error between fitting and measured formation pressure.And the calculation method based on intelligent algorithms was discussed.Moreover,taken A well area in certain gas reservoirs as an example,two optimization algorithms of both whale and particle swarm were used respectively to optimize the function.And the obtained pa-rameters were compared.Results show that(i)the optimal waterbody parameters induced from the whale optimization algorithm are:the radius of waterbody's inner broundary(rw)of 1,101 m,the dimensionless radius of outer boudary(reD)of 5.10,the water-invasion angle(θ)of 25.07°,the storativity ratio(ω)of 0.13,and the interporosity flow coefficient(λ)of 0.00035,while those from the particle swarm optimization algorithm are:rw of 1,030 m,reD of 4.83,θ of 15.68°,ω of 0.21,and λ of 0.00016,respectively;(ii)the relative error between the fitting pressure from the two algorithms and the measured pressure is small(＜5%generally),and the average rela-tive error is 1.36%in the whale algorithm,which is smaller than that of another algorithm(2.01%);and(iii)the whale enjoys fast con-vergence,strong global search ability and simple operation.And the swarm,as an evolutionary algorithm,is characterized by smaller convergence value of objective function.Both algorithms are feasible.The calculation results lay the foundation for analyzing water invasion in gas reservoirs,and the comparison of two algorithms provides not only an additional technique for calculating waterbody parameters in similar gas reservoirs in China but reference for efficient development of such gas reservoirs.
万方数据
维普
