沁南地区煤层气储层特征及敏感性评价

Characteristics and sensitivity evaluation of coalbed methane reservoir in Qinnan area

为实现沁南地区煤层气的高效合理开发,分析了煤层气钻井过程中储层潜在的损害因素,结合研究区块内煤储层特征分析及敏感性评价试验,有针对性的提出了储层保护措施建议。储层特征分析结果表明:目标区块储层内黏土矿物以蒙脱石和高岭石为主,储层平均孔隙度4.58%,储层渗透率小于1 mD,平均孔隙压力系数0.895,地层水水型为NaHCO_3。储层敏感性评价结果表明:研究区块内储层速敏损害程度为中等偏强,水敏损害程度为中等偏强水敏至强水敏,酸敏损害程度均为中等偏强,碱敏损害程度均为中等偏强,应力敏感程度均为强应力敏。根据对目标区块的煤储层特征分析及敏感性评价结果,在煤层气开发过程中应选择合适的钻井液等入井流体,选择合适的钻井工艺和其他工程措施,确保沁南地区煤层气的科学合理开发。

The potential damage factors of coalbed methane drilling process are analyzed in order to sonable development of coalbed methane in Qinnan area. Combining witli the characteristics of coal reservoir and the sensitivity evalua-tion experiment,the reservoir protection measures are recommended. The results show that the montmorillonite and kaolinite are the main clay minerals in the target block reservoir,the average porosity of the clay is 4. 5 8% ,the reservoir permmD,the average pore pressure coefficient is 0. 895,and the water type is NaHCO＂. The results of reservoir sensitivity evaluation showthat the damage level of reservoirs in the study block is moderate and strong,the degree of water damage is moderate to strong water sensitivity and strong water sensitivity,the degree of acid damage is moderate and strong,the degree of alkali damage is moderate and strong, and the stress sensitivity is strong stress sensitive. According to the coal reservoir characteristic anauation result of thie target block,the appropriate drilling fluid should be selected during the development of coallDed methiane. The ap-propriate drilling technolog and othier engineering measures should be selected to ensure the scientific andbed methane in Qinnan area.