鄂尔多斯盆地某矿区储层特征及潜在损害因素评价

采用X射线衍射、压汞实验、岩芯常规物性分析等实验方法,对鄂尔多斯盆地某矿区煤层气储层特征进行了研究,并在此基础上,采用敏感性评价实验对煤储层潜在损害因素进行了研究。结果表明,目标矿区内煤储层主要成分为炭,其次为黏土矿物、黄铁矿、方解石和少量石英;其中黏土矿物主要以蒙脱石、高岭石和绿泥石为主;储层平均孔隙度为4.83%,储层渗透率主要分布在1.5～3.5mD,物性较差。敏感性实验结果表明,目标矿区内煤储层存在较强的应力敏感性,速敏和水敏损害程度均为强,碱敏损害程度为中等偏弱,酸敏损害程度为中等偏强。根据以上储层特征及潜在损害因素评价结果,有针对性地提出适合目标矿区的储层保护措施建议,以期为鄂尔多斯盆地煤层气的高效开发提供保障。

Evaluation of reservoir characteristics and potential damage factors in a mining area of Ordos Basin

The characteristics of coal bed gas reservoir in a mining area in Ordos Basin were studied by X- ray diffraction, mercury pressure test and core conventional physical property analysis. On this basis, the potential damage factors of coal reservoir were studied by sensitivity evaluation experiment. The results show that the main component of the coal reservoir in the target mining area is carbon, followed by clay minerals, pyrite, calcite and a small amount of quartz, and the clay minerals are mainly montmorillonite, kaolinite and chlorite; the average porosity of the reservoir is 4.83%, and the reservoir permeability is mainly distributed among 1.5mD~3.5mD, and the physical property is poor. The results of sensitivity test show that the coal reservoir in the target mining area has strong stress sensitivity, the speed sensitivity and water sensitivity are all strong, the degree of alkali sensitive damage is medium weak, and the degree of acid sensitive damage is moderate. According to the evaluation results of reservoir characteristics and potential damage factors, the suggestion of reservoir protection measures suitable for the target mining area is proposed in order to provide a guarantee for the efficient development of coal bed gas in Ordos Basin.