考虑孔隙和微裂缝的煤层气储层压汞曲线分析模型

发布时间：2018-01-26 07:52

  本文关键词： 孔隙 微裂缝 高煤级煤岩 压汞 最终采收率　出处：《矿物岩石》2017年01期 　论文类型：期刊论文

【摘要】：基于沁水盆地东北部和顺煤层气区块高煤级烟煤储层的物性、压汞及扫描电镜资料,对该煤层气储层的孔隙结构特征进行分析。该煤储层RO值分布在1.8~2.5,为贫煤,其镜质组含量主要分布在62%~80%,平均约为70.02%;惰质组含量主要分布在10%~25%,平均约为18.48%;V/I(镜质组/惰质组)值主要分布在2~30之间。所研究煤储层中的有效空间系统以孔隙和微裂缝为主,建立了同时考虑孔隙和微裂缝的高煤级煤岩阶段入汞及退汞过程曲线模型。入汞曲线模型与煤岩渗透率具有较好的匹配关系,在分析煤岩孔隙系统连通性方面比退汞曲线模型更为可靠。微裂缝相对发育的煤岩渗透率较高,排采初期往往具有较高产能,但其产能递减相对较快,最终会有相当一部分天然气滞留于地层中而无法被开采,因此最终采收率相对较低。微裂缝欠发育的煤样渗透率较低,开发初期产能较低,但其生产周期却相对较长,最终采收率相对较高。因此,对于国内部分地区微裂缝发育情况相对较差的煤储层而言,初产能力可能相对偏低。但从长远来看,由于其最终采收率更高,生产周期较长,最终累积产气量也会更大。该认识可以为煤层气排采开发方案的合理制定提供参考。
[Abstract]:Based on the physical properties, mercury injection and scanning electron microscope data of high-grade bituminous coal reservoirs in the northeastern Qinshui Basin and the coalbed methane block of Shun. The pore structure characteristics of the coalbed methane reservoir are analyzed. The RO value of the coal reservoir is 1.8% 2.5, which is lean coal. The vitrinite content of the reservoir is mainly distributed in 62% ~ 80%. The average value is about 70.02; The content of inertinite is mainly distributed in 10 and 25, with an average of 18.48; The values of vitrinite / inertinite (vitrinite / inertinite) are mainly distributed in the range of 20.The effective space system in the studied coal reservoir is dominated by pores and micro-fractures. The mercury and mercury removal process curve model of high coal rank coal is established, which considers both pores and micro fractures. The mercury injection curve model has a good matching relationship with coal and rock permeability. It is more reliable to analyze the connectivity of pore system of coal and rock than the model of mercury removal curve. The permeability of coal and rock with relatively developed micro-fractures is higher, and the productivity of coal and rock is usually high in the early stage of discharging mining, but the productivity decline is relatively fast. In the end, a considerable part of natural gas will remain in the formation and can not be exploited, so the final recovery factor is relatively low. The permeability of coal samples with underdeveloped micro-fractures is lower, and the initial production capacity is lower. However, the production cycle is relatively long and the final recovery is relatively high. Therefore, for coal reservoirs with relatively poor development of micro-fractures in some areas of China, the initial production capacity may be relatively low, but in the long run. As the final recovery is higher and the production cycle is longer, the final cumulative gas production will also be greater. This understanding can provide a reference for the rational formulation of the development plan of coal bed methane (CBM) exhaust production.
【作者单位】： 北京奥能恒业能源技术有限公司;华北油田公司勘探开发研究院;浙江油田分公司地质与工艺研究院;
【基金】：国家自然科学基金项目(41372139,41072098) 国家科技重大专项专题(2011ZX05018-001-002,2011ZX05009-002-205,2011ZX05033-004)
【分类号】：TE319
【正文快照】： p苝，

本文编号：1465099