中国中阶煤和高阶煤的储层特性及提高单井产量主要对策

中国山西河东地区中阶煤储层的含气量比较低、含气饱和度低，而储层渗透性好，储层能量比较大；山西沁水盆地南部高阶煤储层的含气饱和度比较低，渗透率小，储层能量低。文章针对这些特点，进行了精细的地质对比研究，提出了提高气产量的对策。认为最大限度地降低储层的废弃压力可提高采收率；应通过改善钻井液、采用欠平衡钻井和羽状水平井钻井技术，最大限度地降低钻井工程对煤层气储层造成的伤害；同时还要利用合理的固井程序和水泥浆、套管射孔完井技术和压裂技术；通过排水降压提高有效压差及注入CO₂来达到加快煤层气解吸和提高解吸量的目的。实践表明，该技术对提高单井气产量意义重大。

RESERVOIR CHARACTERISTICS OF MEDIUM-HIGH RANK COAL AND MAIN COUNTERMEASURES TO IMPROVE GAS PRODUCTION OF SINGLE WELL 1)

The reservoirs of the medium rank coal characterize low gas content, low gas saturation, good permeability, and high energy in Hedong area of Shanxi, China. And the reservoirs of the high rank coal characterize low gas saturation, low permeability, and low energy in the south of Qinshui basin, Shanxi. Considering these characteristics, the detailed geologic correlation and research are conducted, and the countermeasures to improve gas production are proposed. It is found the gas recovery factor can be improved by reducing the abandoned pressure of the reservoirs as much as possible. With the improved drilling fluid and the techniques of under-balanced drilling and pinnate horizontal drilling, the damage from drilling operation can be minimized on the coal-bed gas reservoirs. With the proper cementing procedure and slurry and the techniques of casing perforation completion and fracturing, improving the effective pressure difference by water drainage and pressure decrease and injecting CO_2, the purpose can be reached to enhance the desorption rate and amount. The practice shows the method is very helpful to improve gas production of single well.