Well Test Automated Matching Method Based On Response Surface Model

Establishing a reliable geological model is the basis for solving reservoir evaluation,management and development problems,as well as guaranteeing the dynamic prediction of reservoirs and oil wells.Well test analysis is one of the effective ways to obtain formation parameters.Well test analysis is a typical inverse problem that analyzes the formation and wellbore parameters using the time-varying data of the measured bottomhole pressure during shut-in.Based on the response surface method,this thesis presents a numerical well test interpretation method with automatic parameter inversion and a variable analysis method to reduce variables and improve computational efficiency.Firstly,the uncertain parameters and their scope are selected,the trial calculation example is determined,and then the polynomial approximation function is obtained by using the matching method,that is,the response surface model is constructed.The response surface model is used to construct the objective function of the deviation between the calculated value and the observed value.Then the optimal algorithm is used to search the minimum value of the objective function to obtain the uncertain parameter value.The example shows that the method can effectively match the bottom hole pressure and the pressure derivative,so it has a good application prospect.Based on the second-order polynomial model,the computational efficiency can be obviously improved by directly judging the saliency of the variables according to the position relationship of the reservoir parameter and by distance.Then use P significance test and the actual results verify that this method is effective.The main work of thesis includes the following sections:The first part introduces the background and status quo of well testing analysis in detail and the concept of well testing analysis.The second part introduces the response surface method and the commonly used optimization algorithms,including gradient optimization algorithm and intelligent optimization algorithm.The third part introduces the well testing automatic matching method based on the response surface method and the optimization algorithm,carries on the numerical simulation,and automatically reverse the formation and wellbore parameters.The fourth part is based on the second-order polynomial model,which directly reduces the variables according to the geological model and verifies by the numerical results and p-value significance test in statistics.