【作者】 卜凡；

【导师】 闫相祯；

【作者基本信息】 中国石油大学 ， 安全技术及工程， 2011， 硕士

【摘要】 沁水盆地煤层气欠平衡钻井作业是一项复杂、高风险的工程,整个过程存在大量的不确定性以及随机性因素,容易发生多种事故,考虑到设备的大型化以及欠平衡钻井工艺的复杂性,一旦发生事故,将对人身财产造成重大伤害,本文对钻井风险进行评估具有十分重要的实际意义。本文主要是根据沁水盆地地区的实际情况,建立欠平衡钻井风险评估模型。首先是对该地区煤层气欠平衡钻井作业进行风险因素识别与分析,这是较为关键的一步,风险因素分析是欠平衡钻井风险评估的基础和前提。考虑到在煤层中进行欠平衡钻井井壁的稳定性问题,本文在基于FLAC软件基础上建立井壁模型分析井底欠压值以及地应力变化对井壁稳定性的影响。对于欠平衡钻井作业风险评估,本文主要是构造钻井作业风险评估指标体系层次结构图,采用模糊数学以及专家经验对各风险因素进行指标量化,并采用层次分析法及专家意见来确定评估体系各风险因素的权重分配,然后通过模糊综合评判法构建风险评估综合模型,通过求解模型得出评估结果。本文还通过编写欠平衡钻井风险评估软件,将整个复杂的钻井风险评估过程通过软件来计算,能够快速而又准确的得到评估结果,大大提高了评估效率。本文对关键风险因素对钻井风险的影响进行了针对性分析,重点分析了井壁稳定性和钻井液密度等因素对欠平衡钻井的影响,通过改变它们的参数分析风险评估综合值的变化情况。论文还通过编写的评估软件对沁水盆地地区钻井实例进行成功的风险评估,将理论模型、编写的软件与工程实际相结合,便于课题成果的推广。更多还原

【Abstract】 The underbalance drilling in the Basin of Qin Shui is a complex and high risk project. There are a lot of uncertainties and random factors in the whole process so it is prone to a variety of accidents. Taking into account the large-scale equipment and the complexity of technology during underbalanced drilling, in the event of an accident, it will cause significant harm to persons and property once accident happens. So the risk assessment for the underbalance drilling in this paper has very important practical significance.This article is based on the actual situation in the region Qinshui Basin, and establishes the model of risk assessment of underbalanced drilling. First the paper analysis the risk factors of the balanced drilling, the analysis of the risk factor is the basis of the risk assessment for the underbalance drilling. In addition, the paper analysis the stability of wellbore based on FLAC software. The paper establishes the hierarchical structure of the risk factors, and quantifies the risk factors mainly using fuzzy mathematics and expertise method. And then confirm the weight of the risk factors by means of analytical hierarchy process. Finally the paper establishes the model of risk assessment using fuzzy comprehensive method. The paper also composes the risk assessment software for underbalanced drilling, and the whole work of risk assessment can be done through the software, so it greatly improves the efficiency of assessment. The key risk factors are analyzed importantly such as wellbore stability and drilling fluid density. We analyze the value by changing their parameters.The thesis model, the software and the project combine together in this paper, and this facilitates the promotion of project results.更多还原