利用不同压力表示的Horner法、Agarwal法和MDH法在气井压力恢复曲线解释中的应用与对比OA

For closed volumetric gas reservoirs,new wells that have completed gas tests need to first perform a single-point or multi-point productivity testing according to the gas well testing program to determine the absolute open flow rate and inflow performance IPR curve.The gas well is then shut in for a pressure buildup test to determine the original formation pressure,effective permeability,and the total skin factor of the well(St=S1+S2+S3+S4).For new gas wells,currently available methods for interpreting pressure buildup curve including Horner method,Agarwal method,and MDH method using different pressure representations.Among them,the Horner method and the MDH method are the traditional evaluation methods in the world.The Agarwal method was the recommended method in this paper.The Horner method was used to determine the original formation pressure and effective permeability of gas reservoirs.The Agarwal method and the MDH method were used to determine the effective permeability of gas reservoirs and the total skin factor of gas wells.Through the application of an example,it is shown that the evaluation results of three pressure buildup curve interpretation methods represented by different pressure representations are basically the same.This is related to the longer production time(83.3 days,2000 hours)of the gas well before shut-in.