【作者】 张志军；

【导师】 秦勇；

【作者基本信息】 中国矿业大学 ， 矿产普查与勘探， 2016， 硕士

【摘要】 以煤层气地质及勘探开发工程资料为依据,分析了沁水盆地樊庄区块3号煤储层地质条件,构建了以煤层气开发效果为目标函数的高产区优选综合评价体系,预测了高产区分布,进而探讨了煤层气井产能分异的影响因素和作用机制。结果表明,樊庄区块3号煤层具有“四高两低一复杂”的储层地质特点,“四高”表现为煤级高、含气量高、吸附能力高和临储压力比高,“两低”为孔渗性相对较低和储层压力梯度低,“一复杂”即煤体结构复杂。这些特点,一方面决定了樊庄区块煤层气开发地质条件在国内的相对优越性,另一方面要求采取更有针对性的煤储层改造与增产措施。针对煤层气富集条件、煤储层导流能力、开发地质条件三个方面,选取9项评价要素和10项评价参数,采用多层次模糊综合评判法,基于评价要素与煤层气井生产状况拟合关系,建立了区块尺度内煤层气高产区优选评价模型,据此在区块范围内识别出4个一级产能区和6个二级产能区。在此基础上,提出了4个排采动态量化评价参数,采用煤储层静态地质条件与排采动态相结合的研究思路,阐释了原地应力、构造、地下水流体势等静态因素以及气水分异、生产压差等动态因素耦合作用下,导致煤层气井产能分异的因素及机理。研究成果也揭示,统一的“定压排采”制度是造成目前煤层气井产能差异巨大的重要工程原因,对樊庄区块尤为如此。更多还原

【Abstract】 Based on the large amount of the data and information from the exploration and development of vertical CBM wells in Fanzhuang block, Qinshui basin, the geology of No.3 CBM reservoir was discussed, a comprehensive optimization system of CBM sweet spots was set up taking the CBM well drainage effect as an objective function, and the reginal distribution of CBM sweet spots was predicted. Further, the contorling factors and mechanisms of CBM productivity differentiation were discussed. The results show that the geology of No.3 coal reservoir is characteried by the ―four-high, two-low and one-complex‖. The ―four-high‖ means the high coal rank, high CBM content, strong adsorptivity and high ratio of critical desorption pressure to reservoir pressure, the ―two-low‖ is relatively low porosity and permeability and low pressure gradient, and the ―one-complex‖ refers to the complex coal-body structure. These characteristics, on the one hand, show that the geological conditions of CBM development in the block is relatively favorable in China, and, on the other hand, the more targeted measures for coal reservoir reconstruction and CBM production stimulation. In view of the three aspects of geological conditions such as the CBM accumulation, coal reservoir conductivity and CBM drainage geology, a mathematical model of CBM sweet spot optimization within a block based on the fitting relationship between evaluation parameters and CBM production is established using the multilevel fuzzy model, which is consisting of 9 key elements and 10 evaluation parameters. Based on the model, the 4 primary CBM productivity areas including 6 sub-areas were distinguished within the block. Then, the 4 drainage dynamic index of CBM wells were proposed, and the contoling factors and mechanism for the productivity differentiation of CBM wells were interpreted. It was considered that the productivity differentiation was controlled jointly by the revervoir factors such as geo-stress, structure and groundwater level with the drainage dynamic ones such as gas-water separation and production pressure difference. It was also revealed that the productivity differentiation was resulted in a unified "constant pressure" drainage working system, especially in Fanzhuang block.更多还原