低渗致密气井分类评价方法研究 ——以子洲气田为例

由于子洲气田低渗致密气储层地质情况复杂，储层物性差异大，造成子洲气田各井的产量、压力等生产特征不同。为了更好地指导低渗致密气井高效合理的开发，需要基于各井的静态特征和动态规律，对其进行合理的分类。采用储能系数和地层系数两个储层物性参数，作为静态评价指标；采用稳产期累产气量、稳产期日均产气量、平均日产气和单位压降产气量四个动态参数，作为动态评价指标。创造性地提出依据各评价指标频率分布直方图的特征，对气井进行各指标分级。基于正交矩阵的思路，建立了动静结合的低渗致密气井分类评价方法，最终形成了静-动结合的气井分类结果：子洲气田152口低渗致密气井中I类井（储层物性好，实际产量高）占11.2%、II类井（储层物性较差，实际产量高）占8.5%、III类井（储层物性好，实际产量低）占30.3%、IV类井（储层物性差，实际产量低）占50.0%。其中，III类井是今后生产开发的研究重点，明确III类井的范围，可为将来措施提产指明方向。建立的动静结合低渗致密气井分类评价方法，可为类似区块低渗致密气井的分类提供借鉴。

Classification and evaluation methods for low-permeability tight gas wells in the Zizhou gas field

The complex geological conditions, and the anisotropic reservoir properties of tight gas reservoirs in the Zizhou gas field caused significant differences in yields and pressure of wells. In order to design a more efficient and reasonable development strategy for tight gas wells, the gas wells need to be reasonably classified based on the static formation properties and dynamic performance of each well. The reserve coefficient and formation coefficient are chosen as static evaluation indexes, and cumulative gas production in the stabilized gas production stage, average daily gas production in stabilized stage, average daily gas production over the whole range, and daily gas production per tube pressure drop are chosen as dynamic evaluation indexes. Gas wells are classified based on frequency distribution histograms according to each index. Then a static-dynamic coupled classification method for tight gas wells is established on basis of the idea of orthogonal matrix, and a static-dynamic combined classification is performed. Results show that for 152 wells in the Zizhou gas field, wells of type I (good reservoir properties, high actual production) account for 11.2%, type II (poor reservoir properties, high actual production) account for 8.5%, type III (good reservoir properties, low actual production) account for 30.3%, and type IV(poor reservoir properties, low actual production) account for 50.0%, respectively. Especially, wells of type III should be the research focus of further production and development. Defining the distribution of type III wells can help guide the selection of measures to improve production in the future. This static-dynamic coupled classification method can provide a reference for the classification of tight gas wells in similar blocks.