煤层气井多次铺砂压裂工艺

Multi-sanding fracturing technology used for CBM wells

喻鹏 钟炳成 乔豁通 张洋

YU Peng ZHONG Bingcheng QIAO Huotong ZHANG Yang

中国石油华北油田公司采油工程研究院

Oil Production Engineering Research Institute, PetroChina Huabei Oilfield Company, Renqiu062552, Hebei, China

沁水盆地高阶煤储层采用活性水压裂工艺后，直井平均单井日产量仅1 000 m³/d左右。理论分析和压裂监测统计表明，常规活性水压裂工艺存在压裂容易窜层和活性水携砂能力差、支撑距离短的弊端，制约了煤层的改造效果和单井产量的提升。为进一步提高煤层气井压裂改造效率，利用低黏液体携砂能力差、易形成砂堤的特性，提出煤层多次铺砂压裂工艺思路。以裂缝和砂堤为研究对象，根据物质平衡理论，建立了活性水多次铺砂压裂数学模型，同时优化压裂排量、液量和支撑剂粒径等工艺参数。现场试验结果表明，应用三次铺砂压裂工艺大大降低了煤层压窜的程度，压后单井平均日产气量达到2 223 m³/d，验证了三次铺砂数值计算模型指导现场施工的可行性。

After active water fracturing technology is applied to high-rank coal reservoirs in the Qinshui Basin, the average coalbed methane (CBM) production rate of each vertical well is only about 1 000 m/d.It is indicated from theoretical analysis and fracturing monitoring statistics that conventional active water fracturing technology is disadvantageous with easy interlayer communication and poor carrying capacity and short support distance of active water, which restrict the stimulation effect of coal beds and the improvement of single-well production rate.In this paper, the idea of multi-sanding fracturing technology for coal beds was proposed to improve the stimulation efficiency of CBM well fracturing.Fractures and sand banks were taken as the research objects to establish the mathematical model of multi-sanding active water fracturing according to the material balance theory.Meanwhile, the technological parameters were optimized, including fracturing flow rate, fluid volume and proppant grain diameter.And finally, it was tested on site.It is shown that after three-sanding fracturing is adopted, the coalbed fracturing channeling degree is decreased significantly and post-fracturing average CBM production rate of each well is up to 2 223 m/d.It is verified that three-sanding numerical mathematical model is feasible to guide the field construction.

10.13639/j.odpt.2017.03.019