煤层气水平井水力喷射工艺的室内研究

发布时间：2018-01-21 11:37

本文关键词： 煤层气水平井水力喷射喷射成孔室内研究　出处：《西南石油大学》2016年硕士论文　论文类型：学位论文

【摘要】：煤层气作为一种优质、清洁的非常规天然气资源,倍受国内外学者关注。国内煤层气资源丰富,煤层气的高效开发利用在环境保护、能源保障和经济发展等方面具有重要意义。由于煤层内部割理发育,弹性模量较低,而泊松比较高,在水平井钻完井的过程中应力容易发生变化,导致煤层井壁失稳坍塌；并且煤层气井钻成后应力重新分布,近井环形区域内应力升高产生了压实效应,从而造成异常高的破裂压力；同时煤层气井钻进和固井过程中的液体及携带的煤屑、砂粒泥粒等渗入煤层,降低了近井环形区域的渗透率。水力喷射成孔工艺在煤层气中是可行的。它可以在煤层中产生稳定的孔道,能够避免煤层坍塌；在煤层中各个方向喷出不同的孔,扩大了煤层解吸面积,提高了煤层气产量；克服煤层气井井周的应力集中,清除压实效应,增加煤层渗透率；施工工序简单,能够有效地降低煤层气的开采成本。基于此,本文在前人研究基础上,综合运用岩石力学、流体力学、石油工程等多学科知识,在室内采用沁水盆地樊庄区块3#煤层的煤岩作为实验试样,通过物理实验和数值模拟相结合的方法对水力喷射成孔工艺进行了研究,得出以下主要成果和认识：(1)物理实验中孔成倒锥形,主要由圆形截面和V形垂面组成,而且孔内壁十分光滑,也证明了反溅颗粒的磨蚀作用。(2)物理实验中各参数对孔深的影响程度由大到小依次为泵压、磨料浓度和喷嘴直径；对孔径的影响程度由大到小依次为喷嘴直径、磨料浓度和泵压。数值模拟得出的影响程度规律与其一致。(3)通过数值模拟和物理实验结果的对比,发现两者数据有一定的差别,差值在±15%内。物理实验较真实,但重复性差,数值模拟可以多次重复,适用于复杂的条件。(4)优选出一组施工参数为泵压35MPa,喷嘴直径6mm,磨料浓度10%。
[Abstract]:As a kind of high quality and clean unconventional natural gas resources, coalbed methane (CBM) has attracted the attention of scholars at home and abroad. In China, CBM is rich in resources, and the efficient exploitation and utilization of CBM is in environmental protection. Energy security and economic development are of great significance. Due to the development of internal cleats in coal seam, the modulus of elasticity is low, while Poisson is relatively high, and the stress is easy to change during the drilling and completion of horizontal wells. Leading to the collapse of coal seam wall instability; And the stress redistribution in the coalbed gas well after drilling, the increase of the stress in the annular area near the well has the compaction effect, resulting in the abnormal high fracture pressure. At the same time, the liquid and the coal dust carried in the drilling and cementing process of the coalbed methane well, sand and mud particles, etc., infiltrate into the coal seam. The hydraulic jet hole forming process is feasible in coalbed methane. It can produce stable holes in coal seam and avoid coal seam collapse. Different holes are ejected in each direction of coal seam, which expands the desorption area of coal seam and increases the production of coalbed methane. To overcome the stress concentration around the coalbed methane well, to eliminate the compaction effect and to increase the permeability of coal seam; The construction procedure is simple, which can effectively reduce the mining cost of CBM. Based on this, based on the previous studies, this paper synthetically applies multi-disciplinary knowledge such as rock mechanics, hydrodynamics, petroleum engineering and so on. In the laboratory, the coal and rock of coal seam in Fangzhuang block of Qinshui basin were used as experimental samples, and the hydraulic jet hole forming technology was studied by combining physical experiment with numerical simulation. The following main results and understandings are obtained: (1) in physical experiments, the holes are formed into inverted cones, which are mainly composed of circular sections and V-shaped vertical planes, and the inner wall of the holes is very smooth. It is also proved that the degree of influence of parameters on hole depth in physical experiment is pump pressure, abrasive concentration and nozzle diameter. The influence degree of the aperture from big to small is the nozzle diameter, abrasive concentration and pump pressure in turn. The law of influence obtained by numerical simulation is consistent with that obtained by numerical simulation and the results of physical experiments are compared with each other. It is found that there is a certain difference between the two data, the difference is within 卤15%. The physical experiment is more real, but the repeatability is poor, and the numerical simulation can be repeated many times. A group of construction parameters are selected as pump pressure 35MPa, nozzle diameter 6mm, abrasive concentration 10mm.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD842

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