煤层气定向羽状水平井数值模拟技术应用

定向羽状水平井技术是近几年兴起的一项煤层气的增产技术。目前，在煤层气数值模拟的研究方面国内外已经作了大量的工作，但数学模型多为直井压裂井，没有专门描述煤层气定向羽状水平井开采特征的数学模型。对渗流所编制的定向羽状水平井开采煤层气数值模拟软件做了进一步的改进，首先介绍了定向羽状水平井数值模拟软件的数学模型，然后利用该软件对大宁DNP02井进行了产能预测，并计算得出最佳的排采压力。分析预测结果证明，该软件用于煤层气产能预测是可靠的。通过产能预测量化了该地区煤层气勘探开发的前景，最佳井底压力的确定可以对煤层气开发方案设计提供参考，实现了煤层气数值模拟的目的。软件的应用对这一项新技术在我国的推广应用和煤层气的大规模开采能够起到重要的指导作用，并取得较好的经济效益。

THE APPLICATION OF PINNATE HORIZONTAL MULTILATERAL WELL NUMERICAL SIMULATION TECHNOLOGY

Pinnate horizontal multilateral well is an emerging stimulating technology in recent years. So far, considerable study and research on coalbed methane numeric simulation has been done both at home and abroad. Yet, most of the mathematiccal models are for fractured vertical well and no model is specific on production characteristics of coalbed methane pinnate horizontal multilateral well. Based on improvement of coalbed methane pinnate horizontal multilateral well production numerical simulating program developed by Porous Flow & Fluid Mechanics Institute, this paper presents first the mathematical model of pinnate horizontal multilateral well production numerical simulating program and then its application in productivity prediction and optimum production pressure calculation of the Well Daning-DNP02. The analysis of simulation results demonstrates the program is reliable in coalbed methane production forecast. The simulation produces quantitative prediction of the coalbed methane production perspective of that area and recommends optimum bottom hole pressure for designing of production program, serving the purpose of conducting numerical simulation well. The simulation program will considerably promote the extensive use of pinnate horizontal multilateral well in China and coalbed methane production on large scale and better economical gains.