多分支水平井在煤层气开发中的应用机理分析
Analysis on applied mechanism of multiple laterals horizontal well in developing coalbed methane
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摘要: 应用多分支水平井开发煤层气资源,受到煤层地质条件和分支井眼几何形态等主控因素的制约,只有将二者有机结合并进行井身结构优化,才能发挥多分支水平井的效率。多分支水平井增产机理在于能够有效沟通煤层割理和裂缝系统,增加各分支井眼的波及面积和泄气面积,降低裂隙内气液两相流的流动阻力,加速流体的排出,提高单井产量和采出程度。通过对沁水煤层气田的数值模拟与经济评价可知,用多分支水平井开发煤层气具有明显的经济效益优势。Abstract: It is restricted by geologic setting of coal bed formation and geometric configuration of borehole to utilize multiple laterals horizontal well(MLHW) to develop coal bed methane(CBM) resources.Good efficiency can be obtained if only the two aspects above are considered comprehensively and the hole structure is optimized.Mechanisms of MLHW consist in effectively communicating cleats and fracture system,increasing area of multiple laterals well bore spreading and gas drainage,decreasing resistance of two phases flow in fractures,accelerating discharging speed of liquid and enhancing production and recovery percent of reserves.By numerical simulation and economic evaluation for Qinshui CBM Field,it can be derived that MLHW obviously has a superiority of economic benefit in developing CBM.