长宁—威远页岩气井合理生产参数及产能影响因素研究

发布时间：2018-10-13 13:45

【摘要】：美国凭借页岩气的井喷式发展,超越俄罗斯成为了世界第一大天然气生产国。我国页岩气藏的储量与美国相当,具有巨大的开发潜力,但是与美国相比,我国页岩气储层具有埋藏深、压力大的特点,在开发前中期,解吸气量很少,不足以对气井产能形成有效的补充。因此,需要建立一套符合我国的储层特点的页岩气井产能分析和预测方法,研究页岩气井的合理生产参数及产能影响因素,指导页岩气藏高效开发。本文在调研了国内外大量相关文献的基础上,分析研究了页岩气的储存、运移和产出机理,文献相关实验显示出,在页岩气基质渗流中,除孔隙中的游离解吸气之外,还存在天然气由干酪根扩散进入基质孔隙的运移过程。在研究以上渗流机理的基础上,结合Langmuir等温吸附定律及Fick扩散定律,推导了包含游离气渗流、吸附气解吸、干酪根扩散的页岩气渗流微分方程,并根据页岩气井需要进行大型水力压裂的特点,建立了矩形封闭气藏水平井多段压裂的非稳态渗流模型。运用Laplace变换对模型进行求解后,编制了产量拟合及预测程序,对长宁-威远示范区内的页岩气井生产状况进行拟合,结果表明,该模型能够很好的反映示范区内气井的生产特点,适用性较好。最后,根据拟合求得的物性参数场,对不同配产,水平段长度,压裂段数及井距,排距下的页岩气井生产动态进行预测。结果表明,若想快速、高效开发页岩气藏,对于正常压力系统,合理配产量为初期无阻流量的1/2；对于异常高压系统,合理配产量为初期无阻流量的1/4。在现有的工艺技术条件下,认为页岩气井的水平段长度1000m～1200m,压裂段数10～12段,井距300m,排距1800m为宜。
[Abstract]:With shale gas blowout, the United States overtook Russia as the world's largest gas producer. The reserves of shale gas reservoirs in China are comparable to those in the United States and have great potential for development. However, compared with the United States, the shale gas reservoirs in China are characterized by deep burial and high pressure. It is not sufficient to form an effective supplement to gas well productivity. Therefore, it is necessary to establish a set of productivity analysis and prediction methods for shale gas wells in accordance with the reservoir characteristics in China, to study the reasonable production parameters and productivity influencing factors of shale gas wells, and to guide the efficient development of shale gas reservoirs. Based on the investigation of a large number of related literatures at home and abroad, the mechanism of shale gas storage, migration and production is analyzed and studied. The experimental results show that in shale gas matrix percolation, except for the suction of free solution in pores, There is also a migration process of natural gas from kerogen diffusion to matrix pores. On the basis of studying the above seepage mechanism, combined with Langmuir isothermal adsorption law and Fick diffusion law, the differential equation of shale gas percolation including free gas seepage, adsorption gas desorption and kerogen diffusion is derived. According to the characteristics of large hydraulic fracturing in shale gas wells, the unsteady flow model of horizontal well fracturing in rectangular sealed gas reservoir is established. After solving the model by Laplace transform, the production fitting and forecasting program is compiled, and the production condition of shale gas well in Changning-Weiyuan demonstration area is fitted. The result shows that, The model can well reflect the production characteristics of gas wells in the demonstration area, and its applicability is good. Finally, according to the physical property parameter field obtained by fitting, the production performance of shale gas wells with different production ratio, horizontal segment length, fracturing section number and well spacing are predicted. The results show that if the shale gas reservoir is to be developed quickly and efficiently, the reasonable distribution of output is 1 / 2 of the initial unhindered flow rate for the normal pressure system and 1 / 4 of the initial unobstructed flow rate for the abnormal high pressure system. Under the existing technological conditions, it is considered that the length of horizontal section of shale gas well is 1000m ~ 1200m, the number of fracturing section is 10 ~ 12 section, the well spacing is 300m and the spacing is 1800m.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE312

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