煤层气井潜在酸联合加砂压裂增产机理及应用

延长油田股份有限公司 杏子川采油厂,陕西 延安 717400

矿业工程; 煤层岩性; 酸化; 潜在酸; 粘弹性表面活性剂; 压裂液

Mechanism and application of potential acid combined sand and fracturing in CBM wells
GUO Ai-hua

(Xingzichuan Oilfield,Yangchang Petroleum Co.,Ltd.,Yanan 717400,China)

mineral engineering; lithologic characteristics of coal; acidification; potential acid; viscoelastic surfactant; fracturing fluid.

DOI: 10.13800/j.cnki.xakjdxxb.2018.0419

备注

为研究煤层气井潜在酸促进加砂压裂协同增产作业的效果,提高煤层气井采收率,应用扫描电镜分析技术及室内岩心驱替实验的方法,对煤层气储层岩性特征及潜在酸性能进行分析评价,并结合矿场实际效果检验,研究了潜在酸联合加砂压裂增产技术机理及其应用前景。研究表明:煤中含有多种酸溶性碳酸盐矿物主要为方解石(CaCO3),晶体形态有菱面体、似立方体、柱状、板状等,产状有脉状、薄膜状、分散状等形态存在于煤层中,因此可以考虑采用潜在酸酸化技术改造煤层的孔隙度从而提高煤层的渗透率。以氯化铵和多元醛形成的潜在酸,该潜在酸对煤心矿物具有一定的酸蚀性,既可以起到酸化增加孔隙度的作用而增加储层渗透率,又不会因为酸蚀量大而破坏煤的结构,该潜在酸还可以与煤层气清洁压裂液体系配合使用。从PH1-006X1井和PH1-006X2井的现场应用表明,潜在酸与加砂压裂联合增产技术对煤层压裂效果明显,投产即表现出较高的产量。利用煤层气井储层中的碳酸盐矿物生成潜在酸,联合加砂压裂可以有效的提高采收率,具有良好的应用效果。

In ordoer to study the effect of potential acid in coalbed methane wells in improving sand production and fracturing operations and to increase the yield of CBM production,using scanning electron microscope analysis technology and indoor core displacement experiment,the characteristics of CBM reservoir lithology and the properties of potential acid are analyzed and evaluated.Combined with the actual field test effect,technological mechanism of increasing production of potential acid combined sand fracturing and its application prospects are studied.The results show that the coal contains a variety of acid soluble carbonate minerals such as calcite(CaCO3),the crystal morphology is rhombohedral,cubic,columnar,and plate-shaped,and so on,with vein,thin,scattered occurrence in the coal seam.Therefore,reforming the the porosity of coal by acidification technology to improve the permeability of coal seams be considered.The potential acid formed by ammonium chloride and multi-component aldehyde has a certain acid corrosion on the coal core minerals,which increase its permeability without destroying the structure of coal.This potential acid can be used in conjunction with the CBM clean fracturing fluid system.From the field applications of PH1-006X1 well and PH1-006X2 well,it is known that potential acid and sand fracturing combined production technology has obvious effect on coal fracturing because of high yield of primary production.The combination of potential acid formed by carbonate minerals in coalbed gas well reservoir and sand fracturing can increase the recovery rate effectively,and has a good application prospect.