钻井液漏失安全评价钻前预测研究

Predicting Drilling Fluid Leakage before Drilling by Safety Assessment Index

钻井液的漏失是由于某些不可预知的地质因素、工程因素以及人为因素所造成,这些因素无法通过数据形式进行分析。讨论了影响漏失安全的各种因素,建立了影响漏失特征的风险评估体系。影响漏失安全的因素往往是多目标的,在目标因素结构复杂,缺乏必要数据情况下,利用专家的评定,确定影响漏失指标的权重值,将不确定性的因素数量化。并以现场井进行漏失安全评价分析,结果表明该方法具有合理性与科学性,为钻前预测漏失规律安全问题提供了符合客观实际的量化模型。

During the drilling,drilling fluid leakage was induced by unpredicted geologic factors,engineering factors and human factors,these factors could not be analyzed by data.All kinds of the factors influenced the safety of drilling fluid were discussed,and its safety assessment index system was determined.The factors that influenced the drilling fluid safety were multi-goals,under the condition of complex goal structures and lack of necessary data,a methodology was presented to determine the leakage index weight and quantify uncertain factors by experts.Wells in the oilfield are used for evaluating,the result shows that the safety assessment index system and methodology are scientific and reasonable.It provides a quantificational model for systematical evaluation of leakage rules.