煤层气产能主控因素及开发动态特征研究

发布时间：2018-03-17 23:41

  本文选题：煤层气产能　切入点：主控因素　出处：《中国矿业大学》2017年博士论文　论文类型：学位论文

【摘要】：本文以鄂尔多斯盆地东缘保德区块煤储层地质和排采特征为依据,首先从地质条件、工程技术和排采控制三个方面,系统分析保德区块煤层气产能主控因素,并利用灰色关联分析法对这些产能影响因素进行了定量化研究。其次,从储层压力变化,井间干扰特征、储量动态评价三个方面,揭示了煤层气排采过程中煤储层的动态变化特征。在此基础上,从开发有利区划分、井网部署优化和排采控制方法三个方面,系统提出保德区块煤层气产能调控的技术方法和措施。取得了以下主要研究成果和认识:(1)通过地质条件、工程技术和排采控制三个方面的系统研究,揭示了保德区块煤层气产能主控因素及其作用机理,并采用灰色关联分析法对这些产能影响因素进行了定量化研究。煤层厚度、地下水流体势、含气量、渗透率和临储比是影响保德区块煤层气产能的主要地质因素;井距大小、总压裂液量、加砂量是影响产能的主要工程技术因素;井底压力下降速度、动液面下降速度、套压直接影响煤层气产能。采用灰色关联分析法最终得出研究区煤层气产能主控因素由强到弱依次为:临储比地下水流体势等效厚度等效含气量等效加砂量等效压裂液量等效渗透率平均井距。(2)以典型事例的深刻剖析为基础,构建了压降模型,阐释了煤层气排采过程中煤储层的动态变化特征。揭示了煤层气排采过程中储层压力变化特征及规律,获得了单井和多井单相液体稳定渗流时任意一点的压力表达式,模拟了单井储层压力的变化情况,提出了压降漏斗影响因素。利用实际生产中主要采用的两种井间干扰观察方法,系统分析了研究区的井间干扰特征及其对煤层气产能的影响,并提出了井间干扰的应用途径。计算出研究区煤层气动态储量,重新估算了静态地质储量,并进一步分析了储量动用程度和采出程度。(3)通过开发有利区划分、井网部署与优化调整、排采控制方法三个方面的系统研究,提出了保德区块煤层气产能调控的具体措施和方法。构建了煤层气开发有利区评价指标体系,将开发有利区划分为4种类型,包括开发条件有利区、开发条件较好区、开发条件适中区、开发条件较差区。提出了井网部署与优化调整方案,将井网优化划分为开发前期井距设计、现场井距优化、后期井网调整3个阶段,并提出煤层气井抽采方式调整方案。将保德区块煤层气排采过程划分为排水、产气前、初始产气、产气上升、产气稳定和产气下降六个阶段,并针对不同排采阶段,提出了具体的排采控制措施,并深入分析了不同地质条件下典型排采井的控制差异性。
[Abstract]:Based on the geological and drainage characteristics of coal reservoir in Baode block on the eastern edge of Ordos Basin, this paper first systematically analyzes the main factors of coal bed methane productivity control in Baode block from three aspects: geological conditions, engineering technology and drainage control. These factors are quantitatively studied by grey relational analysis. Secondly, from three aspects of reservoir pressure change, interwell interference characteristics, reserves dynamic evaluation, The characteristics of dynamic change of coal reservoir in the process of coal bed methane production are revealed. On the basis of this, from three aspects, the division of favorable areas for development, the optimization of well pattern deployment and the method of drainage control, The technical methods and measures for the control of coalbed methane productivity in Baode block are systematically put forward. The following main research results and understanding are obtained. The main controlling factors and their action mechanism of coalbed methane productivity in Baode block are revealed, and the influence factors of coal seam thickness, groundwater fluid potential and gas content are quantitatively studied by grey correlation analysis. Permeability and reservoir ratio are the main geological factors that affect coalbed methane productivity in Baode block; the size of well spacing, total fracturing fluid quantity and sand addition are the main engineering technical factors affecting productivity; The main controlling factors of coalbed methane productivity in the study area are obtained as follows: equivalent thickness of groundwater fluid potential equivalent gas content equivalent sand content in order of strong to weak. The average well spacing of equivalent permeability of fracturing fluid is based on the deep analysis of typical cases. The pressure drop model is constructed, and the dynamic change characteristics of coal reservoir during coal bed methane production are explained, and the characteristics and rules of reservoir pressure change during the process of coal bed methane discharge and production are revealed. The pressure expressions of any point in single or multi-well single phase liquid steady seepage flow are obtained, and the variation of single well reservoir pressure is simulated. The influence factors of pressure drop funnel are put forward. The characteristics of interwell interference and its influence on coalbed methane productivity are systematically analyzed by using two kinds of observation methods of interwell interference, which are mainly used in practical production. The dynamic reserves of coalbed methane in the study area are calculated, the static geological reserves are reestimated, and the extent of reserve production and recovery is further analyzed. This paper systematically studies three aspects of well pattern arrangement and optimization adjustment and production discharge control method, puts forward the concrete measures and methods of coalbed methane productivity control in Baode block, and constructs the evaluation index system of coal-bed methane development favorable area. The development favorable areas are divided into four types, including favorable development conditions, good development conditions, moderate development conditions and poor development conditions. The well pattern optimization is divided into three stages: well spacing design in the early stage of development, field well spacing optimization, and well pattern adjustment in the later stage, and the adjustment scheme of the extraction and production mode of the coalbed gas well is put forward. The process of coal bed methane production in Baode block is divided into drainage and before gas production. There are six stages of initial gas production, gas production rise, gas production stability and gas production decline. According to different production stages, the specific measures of drainage production control are put forward, and the control differences of typical drainage wells under different geological conditions are analyzed in depth.
【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TE37
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本文编号：1627051