基于突变理论的煤层气井产量预测研究

Application of the Catastrophe Theory in the Quantitative Evaluation of Coalbed Methane High-production Zone

高产区评价是煤层气高效开发的关键环节,为研究突变理论在煤层气储层高产区定量评价中的可行性,在系统梳理煤层气高产区主控因素基础上,建立了高产区评价指标体系,并根据突变理论计算了高产区评价指标(S),将其与实际日产气量进行了对比分析。结果表明:从煤层含气性、解吸效率和产出能力3个方面建立的高产区评价指标体系能够有效预测高产区。根据突变理论计算得到高产区评价指标(S)与日产气量具有较强的相关性,单井日产气量随煤层气高产区评价指标(S)增加而增加,当高产区评价指标(S)大于0.6时,日产气量一般在1 000 m^3以上。因此利用突变理论能够有效预测煤层气储层高产区,该理论为煤层气高产区预测提供了有效的手段。

High production zones evaluation is a key link for the efficient development of coalbed methane. In order to study the feasibility of the application of catastrophe theory in the quantitative evaluation of the high production zones of coalbed methane reservoir, the index system for the evaluation of high production zones was established on the basis of the systematic analysis of the main controlling factors of high production zones. The evaluation index of high production zones, denoted as S, was calculated based on catastrophe theory,and the value was compared with the actual daily production. The results show that the evaluation index system of high production zones, including coal seam gas bearing, desorption efficiency and output capacity, can effectively predict high producing zones. The evaluation index of high production zones calculated by catastrophe theory has a strong correlation with the daily gas production,and the daily gas production increases with the increase of the evaluation index S. When the value of the evaluation index is greater than 0.6, the daily gas production is generally above 1 000 m^3. Therefore, the catastrophe theory can be used to predict the high production zones of coalbed methane reservoir effectively, which provides an effective means for the prediction of high production zones coalbed methane reservoir.