Assisted history matching and graphical methods for estimating individual layer properties from well testing data in stratified reservoirs with multilateral wells

Calculation Model of Drainage Radius of Single-Layer/Multi-Layer Commingled Gas Production Wells in a Closed Constant-Volume Gas Reservoir and Its Application

“…Galvao and Guimaraes [9] developed the delta transient method (DTM) to obtain the permeability and skin coefficient of each layer of a multi-layered infinite formation, and extended the method to multiple flow-rate schemes [10]. Bela et al [11] extended the DTM method to the horizontal wellbore model in order to obtain individual layer permeabilities and skin factors of stratified reservoirs with multilateral wells. Sallam and El-Banbi [12] and Juell and Whitson [13] attempted to analyze multi-layered commingled gas reservoirs using an iterative workflow.…”

“…However, the above models could only compute the average drainage radius for the gas well with a single layer [2][3][4][5][6][7][8]. Although some studies [9][10][11][12][13] have involved multi-layer commingled gas production wells, a clear calculation formula of the drainage radius of these wells was not proposed. In addition, although the well test data required for calculation of the drainage radius can be obtained by using the pressure drawdown test and pressure buildup test, its accuracy from pressure drawdown test is easily affected by many factors, while the long shut-in time required for pressure buildup test can seriously impact the production of gas field and the economic feasibility of gas reservoir development [14][15][16][17].…”