压裂液对煤岩气藏渗流性能的影响  

Effect of fracturing fluids on the seepage properties of coalbed gas reservoirs

作　　者：高波[1] 康毅力[2] 史斌[1] 游利军[2] 张晓磊[1] 皇凡生 

机构地区：[1]中海油能源发展股份有限公司工程技术分公司 [2]"油气藏地质及开发工程"国家重点实验室.西南石油大学

出　　处：《天然气工业》2015年第9期64-69,共6页Natural Gas Industry

基　　金：国家重点基础研究发展计划(973计划)项目"深井复杂地层漏失与井壁失稳机理及预测"(编号:2010CB226705-01)

摘　　要：水力压裂是实现煤岩气藏工业开采的主要增产措施,但煤岩气藏压裂过程中压裂液滤失严重、返排率低,将直接影响排水采气过程中地层水以及煤层气的渗流性能。为此,选用沁水盆地上石炭统—下二叠统太原组15号煤为研究对象,开展了低伤害活性水压裂液对煤岩气藏渗流性能的损害评价实验,并结合红外光谱和扫描电镜等微观分析手段对比了压裂液作用前后的煤岩表面特征和孔隙结构特征,进而深入分析了压裂液影响煤岩气藏渗流性能的微观机理。结果表明:无论宏观裂隙煤样还是显微裂隙煤样,气体渗透率损害率均明显大于液体渗透率损害率且宏观裂隙煤样渗流性能损害程度略大于显微裂隙煤样;压裂液作用后煤岩表面游离态羟基和羧基官能团增多,亲水性增加,压裂液吸附滞留现象严重,煤岩孔径及裂缝宽度变小,从微观角度揭示了煤岩气藏渗流性能下降的原因。该研究成果可为煤岩气藏压裂液配方优化和产能预测提供基础参数。Hydraulic fracturing is a major stimulation measure for industrial exploitation of coalbed gas reservoirs. During the fractu ring of coalbed gas reservoirs occur serious lost circulation and low flowback rate, which have a direct effect on the seepage properties of formation water and coalbed gas in the process of gas recovery by water drainage. In view of this, damage evaluation experiment of low-damage active water fracturing fluid on coalbed gas reservoir seepage properties was carried out with No.15 coal of Taiyuan For- mation, Upper Carboniferous - Lower Permian in the Qinshui Basin as the study object. Then, the surface characteristics and pore structure characteristics of coals are compared before and after fracturing fluids are used by means of microscopic analysis technolo- gies （infrared spectrum and Scanning electron microscope）. And finally, further study was performed on the microscopic effect mechanisms of fracturing fluids on combed gas reservoir seepage properties. Experimental results show that gas permeability damage rate is remarkably higher than liquid permeability damage rate no matter whether it is a macrofraeture coal sample or a microfracture coal sample, and seepage property damage ratio of the macrofraeture coal sample is slightly higher than that of the microfracture coal sample. After fracturing fluids are used, the amount of free hydroxyl and carboxyl functional groups on the surface of coals rises, water wet tability increases, fracturing fluids are adsorbed and detained seriously, and pore diameter and fracture width of the coals decrease. These phenomena reveal, from the point of microscope, the reasons for the decline of coalbed gas reservoir seepage properties. These research find- ings provide basic parameters for fracturing fluid formula optimization and deliverability prediction of coalbed gas reservoirs.

关 键 词：煤层气 排水采气 压裂液 储层损害 渗透率 红外光谱 扫描电镜 沁水盆地 石炭—二叠纪 

分 类 号：TE312[石油与天然气工程—油气田开发工程]