Classification and Estimation of Gas Wells in Sulige Gas Field Based on Mathematical Statistics

Abstract

Sulige gas field is a typical sandstone lithologic gas reservoir with characteristics of low pressure, low permeability and low abundance. Sulige tight gas reservoirs are characterized by complex internal structures of sand bodies, and thin and dispersed gas layers with strong heterogeneity, thus the productivity of gas wells varies greatly. Therefore, the idea of classified evaluation was adopted for the gas wells in the field. Based on reservoir parameters and gas well productivity, the gas wells are classified into three types: I, II and III. But the classification of some gas wells based on static parameters at the initial stage of production did not correspond with the dynamic characteristics at the late stages. According to the production performance data of ten thousand of gas wells, skewed distribution is adopted for the classification of different types of gas wells for the first time. Then the gas well classification standards of Sulige gas field are adjusted and the parameters of different types of gas wells are estimated. The production performance characteristics of different types of gas wells are more accurate based on the new classification standards and it can guide the production of gas wells. The skewness distribution also has application prospect in reserves evaluation.