基于层次分析法的地层钻井液漏失概率判定

Probability Determination for Loss Circulation of Drilling Fluids Based on Analytic Hierarchy Process

对待钻层段漏失发生概率进行评价分级,是做好防漏治漏的前提和基础性工作。针对漏失通道复杂性和随机性的特点,引入层次分析法将控制井漏的各种地质因素及邻井资料等因素层次化,逐层比较各因素重要性,建立易量化指标的隶属度函数,采用加权合成得到最终的井漏概率评价值,并实例说明该方法在塔河油田钻井实践中的应用。实例井计算结果表明,使用层次分析法对地层漏失概率进行综合评判具有可行性。

Lost circulation control is one of the technical problems which impose a negative effect on security, smooth, and highly effective drilling. Geologic and engineering factors are of a major impact on mud loss. The geologic agent is an internal cause and plays a decisive effect. As the premise and the foundation of loss control, it is necessary to grade probability of the intervals with loss potentials. In view of the complexity and random characteristic of lost circulation zones, Analytical Hierarchy Process （AHP） is introduced to analyze the structure of the factor system. By comparing the importance of isostrate factors, constructing an easily quantified membership function, and by using the weighting synthesis, the final lost circulation appraisal value has been obtained. Finally, this AHP assessment method is applied to two case wells in Tahe Oilfield. The results indicated that probability evaluation of lost circulation zones by AHP method is feasible, and is helpful for loss control design and technology optimization.