【作者】 赵鹏；

【导师】 吴财芳；

【作者基本信息】 中国矿业大学 ， 矿产普查与勘探， 2024， 硕士

【摘要】 新景矿现有多口煤层气井进行煤层气地面开发,但是由于煤层气井不同排采阶段储层参数动态变化规律与井网方案优化之间关系尚未厘清,严重影响着煤层气井产能和井网优化设计。因此,本论文在分析新景矿15#煤层煤层气井地质资料和排采资料的基础上,结合物理模拟和数值模拟,研究了15#煤层煤层气井不同排采阶段的排采特征,揭示了排采过程中储层关键参数的动态变化规律及其对井网优化的影响;提出了各类型煤层气井组的最优井型、井组样式、井组方位和井间距,构建了煤层气开发井网优化方法。基于煤层气井地质、排采资料,结合工业分析、元素分析、岩石三轴实验和等温吸附实验,分析了研究区15#煤层煤层气地质条件。15#煤层属于高热值中硫低灰无烟煤,吸附解吸能力较强,具有低压、富气、低渗的特点。将日产气量300 m~3/d和600 m~3/d作为阀域,划分了15#煤层煤层气井产能类型,提出了新六段式排采阶段划分方法,分析了各类型煤层气井在各个排采阶段的气水产出特征。利用数值模拟和物理模拟方法,研究了新景矿15#煤层煤层气井储层动态变化规律及其对井网优化的影响。在排采过程中井底流压、储层压力与渗透率变化特征相近,处于持续降低的趋势,且降低速率逐级递减,整体曲线降幅表现为先急后缓。其中,渗透率主要受到有效应力效应与基质收缩效应的影响,有效应力效应在排采过程中占主导地位。含气量在排采过程中处于下降的趋势,下降幅度由井口向外逐渐降低。研究认为,煤储层关键参数变化特征愈趋于合理的变化规律,单井井控排采边界愈大,采用井组开发煤层气时井间干扰强度愈高,井组的合理井间距愈大。基于数值模拟方法,开展了15#煤层煤层气井井网优化研究。结果表明,适宜15#煤层的井型为:从式井为主,辅以直井;最优井组样式为菱形;井网部署的最佳方位为NE0～40°;采用菱形井网开发煤层气时,为了尽可能提高经济效益,应当选取225 m作为相对高产井的开发井距,选取200 m作为相对中产井的开发井距。相对低产井条件较差,即使采用井组开发也难以达到预期成效,因此予以否决。最终提出了井网优化方法,主要通过对井型、井网方位、井组样式以及井间距进行层层优选,进而得到井组开发煤层气时的最佳参数。本论文共有图72幅,表23幅,参考文献139篇。更多还原

【Abstract】 There are a number of coalbed methane Wells in Xinjing Mine for surface development of coalbed methane,but the relationship between the dynamic variation of reservoir parameters in different discharge and production stages of coalbed methane Wells and the optimization of well pattern has not been clarified,which seriously affects the productivity of coalbed methane Wells and the optimal design of well pattern.Therefore,on the basis of analyzing the geological data and drainage and production data of 15# coalbed methane well in Xinjing Mine,combined with physical simulation and numerical simulation,this thesis studies the drainage and production characteristics of 15# coalbed methane well in different drainage and production stages,and reveals the dynamic change law of key reservoir parameters in the drainage and production process and its influence on well pattern optimization.The optimal well type,well group pattern,well group orientation and well spacing of each type of coalbed methane well group are put forward,and the optimization method of coalbed methane development well pattern is constructed.Based on coalbed methane well geological and drainage data,combined with industrial analysis,elemental analysis,rock triaxial experiment and isothermal adsorption experiment,the geological conditions of 15# coal seam in the study area are analyzed.15# coal seam belongs to high caloric value medium sulfur low ash anthracite with strong adsorption and desorption capacity and features of low pressure,rich gas and low permeability.Taking the daily gas output of 300 m3/d and 600 m3/d as the valve domain,the productivity types of 15# coalbed methane Wells are divided,a new six-stage drainage stage classification method is proposed,and the gas and water production characteristics of each type of coalbed methane Wells in each drainage stage are analyzed.By using numerical and physical simulation methods,the dynamic variation of coalbed methane well in 15# coal seam and its influence on well pattern optimization are studied.In the process of drainage and production,the variation characteristics of bottomhole flow pressure,reservoir pressure and permeability are similar,and they are in a continuous decreasing trend,and the decreasing rate is gradually decreasing,and the overall curve decline is first rapid and then slow.Among them,the permeability is mainly affected by the effective stress effect and the matrix contraction effect,and the effective stress effect plays a dominant role in the drainage process.In the process of drainage and production,the gas content is in a decreasing trend,and the decreasing range gradually decreases from the wellhead to the outside.The research shows that the more the variation of key parameters of coal reservoir tends to be reasonable,the larger the production boundary of single well,the higher the inter-well interference intensity and the larger the reasonable well spacing of well groups when using well groups to develop CBM.Based on the numerical simulation method,the optimization research of coalbed methane well pattern in 15# seam was carried out.The results show that the well type suitable for 15# coal seam is as follows: main shaft,supplemented by vertical shaft;The optimal well group pattern is diamond shape.The best orientation of well pattern deployment is NE0～40°.In order to improve the economic benefit as much as possible,225 m should be selected as the relative high production well spacing,and200 m should be selected as the relative middle well spacing.The conditions of relatively low production Wells are poor,and it is difficult to achieve the expected results even if the well group is used for development,so it is rejected.Finally,the optimization method of well pattern is put forward,which is mainly through the optimization of well type,well pattern orientation,well group pattern and well spacing,so as to obtain the best parameters when the well group develops coalbed methane.There are 72 figures,23 tables and 139 references in this thesis.更多还原