鹤岗、鸡西矿区原位煤层气藏开发类型判识研究

发布时间：2018-09-14 08:14

【摘要】：本文以鹤岗、鸡西矿区各矿井主采煤层为研究对象,采用地质分析、井下描述、实验测试分析以及模糊数学分析相结合的手段,分析了鹤岗、鸡西矿区不同煤储层特征参数的变化规律及其对煤层气藏的指示作用,定义并划分了煤层气藏类型,建立了研究区煤层气藏类型判识指标体系和标准,评判了研究区气藏类型并为不同类型气藏开发技术模式的选择提出了建议。分析研究表明:随着煤体破坏程度的加大,煤体坚固性系数降低,自由基浓度增加,同时随着煤中的外生孔数量增加,不仅增加了煤孔隙的总孔容、大孔孔容及中孔孔容,还使微孔孔容及微孔比表面积大幅度增加,使得构造煤煤体破坏程度越高,吸附能力越强,储气能力越强,这些参数反映了不同煤层气藏的储集特征差异性;研究区构造硬煤所表现出来的高渗透率、高临储比、高含气饱和度、高储层压力梯度等储层特征参数指示了压降容易且可采用原位煤层气开发方式的煤层气藏,而构造软煤原位条件下的低渗透率、低临储比、低含气饱和度、低储层压力梯度等参数是原位煤层气开采的不利因素,但卸压后的高渗透率、高解吸能力、高扩散能力则可使煤储层压降大范围传递,煤层气可得到大规模解吸和顺利产出,这种储层类型的特征参数指示了可采用卸压的非原位煤层气开发方式的煤层气藏。研究区储层特征分析表明,由于煤体结构的不同而导致了煤储层开发方式的分异性。因此,基于煤体结构控制的储层分异,将煤层气藏划分为储层压力可传导型气藏、压力主导型气藏、应力主导型气藏以及应力封闭型气藏四种气藏,并选取煤体坚固性系数、自由基浓度、兰氏体积、临储比、解吸效率、含气饱和度、渗透率、兰氏压力、扩散系数、储层压力梯度等指标参数建立煤层气藏二级判识指标体系和标准,评价了研究区采样煤层的气藏特征,并针对不同煤层气藏类型提出了开发技术模式建议,即压力主导型气藏可采用疏水降压的开采模式,应力主导型气藏可采用应力释放增透卸压的开采模式。
[Abstract]:In this paper, the main coal seams in Hegang and Jixi mining areas are taken as the research objects. By means of combining geological analysis, underground description, experimental test analysis and fuzzy mathematics analysis, the variation regularity of the characteristic parameters of different coal reservoirs in Hegang and Jixi mining areas and their indicative effects on coalbed methane reservoirs are analyzed, and the types of coalbed methane reservoirs are defined and classified. The results show that with the increase of coal destruction degree, the coal body firmness coefficient decreases and the free radical concentration increases. At the same time, with the increase of outer pore in coal The increase of quantity not only increases the total pore volume, macropore volume and mesoporous pore volume of coal pores, but also greatly increases the pore volume and specific surface area of micropore. The higher the destructive degree of structural coal, the stronger the adsorption capacity, and the stronger the gas storage capacity, these parameters reflect the difference of reservoir characteristics of different coal-bed methane reservoirs. Reservoir characteristic parameters such as high permeability, high impending reserve ratio, high gas saturation and high reservoir pressure gradient indicate coalbed methane reservoirs with easy pressure drop and in-situ coalbed methane development mode, while in-situ coalbed methane reservoirs with low permeability, low impending reserve ratio, low gas saturation and low reservoir pressure gradient are in-situ coals. However, high permeability, desorption capacity and diffusion capacity after pressure relief can make the pressure drop of coal reservoir transmit in a wide range, and coalbed methane can be desorbed and produced smoothly on a large scale. The characteristic parameters of this reservoir type indicate the coalbed methane reservoir which can be developed by pressure relief in non-in-situ. Characteristic analysis shows that the development mode of coal reservoir is different because of the different coal body structure. Therefore, based on the reservoir differentiation controlled by coal body structure, CBM reservoir is divided into four types: reservoir pressure conductive gas reservoir, pressure-dominated gas reservoir, stress-dominated gas reservoir and stress-sealed gas reservoir, and coal body is selected to be strong. Parameters such as property coefficient, free radical concentration, Langmuir volume, imminent reserve ratio, desorption efficiency, gas saturation, permeability, Langmuir pressure, diffusion coefficient, reservoir pressure gradient etc. are used to establish the secondary identification index system and criteria for coalbed methane reservoirs. The characteristics of coal-bed methane reservoirs sampled in the study area are evaluated, and development techniques are proposed for different types of Coalbed methane reservoirs. The model suggests that hydrophobic depressurization can be adopted in pressure-dominated gas reservoirs and stress-dominated gas reservoirs can adopt stress release, permeability enhancement and pressure relief.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE37

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