岩浆活动对西山煤田煤储层物性的差异改造特征

为探讨岩浆侵入带来的高温热效应对西山煤田的煤储层物性的差异改造特征，在盆地模拟的基础上，以西山煤田西区煤岩为研究对象，系统采用反射率测试、工业分析、核磁共振、等温吸附、低温液氮吸附、显微裂隙统计等实验手段对距岩浆岩体远近不同的煤样进行实验测试，结果表明离岩浆侵入中心距离不同，储层的孔形、孔径、吸附规律等都表现出差异演化特征，如距岩体越近，煤层反射率明显增大、挥发分较低、灰分增大、BET和孔容增大、瓦斯吸附能力为低-高-低的趋势。在高温、高压的双重作用下，煤层形成了大量岩浆诱发成因的煤层割理，普遍提高了煤层的渗透率。研究结果表明，岩浆活动对西山煤田煤储层物性的改造具有双重性，研究区的中西部屯兰和石千峰一带是储层综合物性条件最佳的地区，是煤层气富集高产的有利区带。

Magmatism effect on different transformation characteristics of coal reservoirs physical properties in Xishan coalfield

In order to investigate the difference transformation characteristics of coal reservoirs’ physical properties in Xishan coalfield that resulted from thermal effects of high temperature magmatic intrusion causes，based on basin simulation，combing with several experimental methods including reflectance test，industrial analysis，nuclear magnetic resonance，isothermal adsorption，low temperature nitrogen adsorption，and micro fracture statistics，the coal samples，which were taken at different distances from the magmatic rock，were tested.Results show that the pore shape，pore size，and adsorption law have different characteristics as the distance from the center of magma intruded changes.As the distance from magma changes to shorter，the coal reflectivity increases obviously，volatile reduces and ash content increases，at the same time，the BET and pore volume increases and the gas adsorption capacity shows the regularity from low to high，then to low.In addition，in the dual roles of high temperature and high pressure，coal seam forms a large number of cleat，originating from igneous intrusion，which improves the permeability of coal seam.The above results indicate that the transformation from igneous intrusion to coal reservoir has dual roles for exploration and development.At last，it concludes that the reservoir physical property of Tunlan and Shi Qianfeng areas in the middle-west region of Xishan coalfield are in the best condition.They are the favorable zones for coalbed methane enrichment and high yield.