基于聚类分析的煤层气二次压裂选井选层方法研究

山西沁水盆地柿庄南区块煤层气井初次压裂生产多年后整体产气量下降,迫切需要进行二次压裂以提高产能,而目标井段的选取对二次压裂的设计施工及增产效果具有极为重要的影响。针对区块二次压裂试验井数少、样本数量有限的问题,提出基于聚类分析的煤层气二次压裂选井选层方法。综合考虑地质储量、可压性和工程三方面因素建立二次压裂选井的层次聚类模型；再根据施工曲线特征设置压裂风险短路条件,排除复压风险高的井,并结合聚类集成算法,最终确定每口井的复压潜力大小。以本区块15口井为例开展了各井二次压裂改造潜力评价,优选B01井为目标井,二次压裂后取得了较好的增产效果。该研究可为井数有限条件下的二次压裂选井选层提供一种有效方法,为后续压裂生产提供依据和借鉴。

Study on Secondary Fracturing Candidate Selection of Coalbed Methane Based on Clustering Analysis

After years of first fracturing of coalbed methane wells in Shizhuang south block of Qinshui basin, Shanxi Province, the overall gas production has declined, and it is urgent to carry out secondary fracturing to improve the production capacity, and the selection of target wells has a very important impact on the design and construction of secondary fracturing and the stimulation effect. In order to solve the problem of low number of secondary fracturing test wells and limited number of samples in the block, the method of fracturing candidate based on clustering analysis was proposed. Firstly, considering geological reserves, compressibility and engineering factors, the hierarchical clustering model of secondary fracturing well selection was established; then, according to the characteristics of construction curve, fracturing risk short-circuit conditions are set to exclude wells with high overpressure risk. Combined with clustering integration algorithm, the secondary fracturing potential of each well was finally determined. Taking 15 Wells in this block as examples, the potential of secondary fracturing for each well was determined, and well B01 was selected as the target well. After the secondary fracturing, a good stimulation effect was achieved. This study can provide an effective method for well and layer selection under the condition of limited number of wells, and provide basis and reference for subsequent fracturing production.