| At present,because of the low productivity of single layer,most of low permeability tight gas reservoirs adopt combined production.However,there are some problems in combined production wells,such as difficult production splitting,interlayer interference and unclear seepage mechanism.At the same time,the current method can only calculate the dynamic reserves of existing wells,which makes it difficult to accurately calculate the dynamic reserves of the whole area of this type of gas reservoir,thus affecting the accurate formulation of development plans.Aiming at this problem,taking the low permeability tight gas reservoir in Linxing block as an example,the production splitting of combined production wells,the calculation of single well dynamic reserves,the division of gas reservoir flow units and the calculation of dynamic reserves by flow unit method are studied.Firstly,the formation coefficient method,energy storage coefficient method and catastrophe theory method are used to divide the production of each layer.The analysis results show that the catastrophe theory method is the closest to the test results of gas production profile.Then,based on the constraints of well test model,the dynamic reserves of single well are calculated by pressure drop method,differential curve method,pressure recovery method and production instability method,and the dynamic reserves of each gas well are divided into different layers according to catastrophe theory.Next,the flow units are divided by the fuzzy C-means clustering algorithm,and the results are imported into the geological model.Finally,the dynamic reserves of the unused part of the reservoir are determined by analogy method using the method of flow unit facies modeling in geological modeling,and the distribution scale of remaining reserves is studied by using dynamic reserves and the "dessert area" of reserves is screened.Accurate calculation of dynamic reserves of gas wells is very important for studying the utilization degree of gas reservoirs and evaluating the remaining development potential of gas reservoirs.The method of calculating dynamic reserves based on Flow Units adopted in this paper has certain practical significance for calculating dynamic reserves of low permeability tight gas reservoirs. |
