面向溢流与井漏监测的钻井液池体积趋势校正方法

Mud Pit Volume Trend Correction for Kick and Lost Circulation Monitoring

钻井液池体积是溢流和井漏监测的常用参数。在钻井正常施工时,随着井筒容积的变化以及井筒内钻井液与地层流体的交换,钻井液池体积会产生与溢流和井漏发生时相似的“类风险趋势”,导致现有的溢流与井漏监测方法易产生误报,降低了溢流与井漏监测方法在现场应用时的有效性。针对此问题,文章首先分析了导致池体积产生“类风险趋势”的原因,建立了钻进与起下钻工况下池体积的正常变化模型,利用建立的模型校正池体积的“类风险趋势”,降低溢流与井漏监测的误报率;然后,建立了基于规则推理的溢流与井漏监测模型,用于测试池体积的“类风险趋势”对溢流与井漏监测的影响。利用现场实测的4500组钻井数据,采用基于规则推理的溢流与井漏监测方法开展了风险监测实验,结果表明,在进行池体积趋势校正后,溢流与井漏风险监测的误报率由10.03%降低至3.06%。

Mud pit volume is often used to monitor kick and lost circulation.During normal drilling operations,with the change of the wellbore volume and the exchange of drilling and formation fluids in the wellbore,the mud pit volume usually has a risk-like trend similar to that of kick and lost circulation,which leads to false alarms when existing kick and lost circulation monitoring methods are applied.In order to address this problem,the causes of the risk-like trend of mud pit volume are analyzed,and mud pit volume change models under the drilling and tripping conditions are established,which are used to correct the risk-like trend of the mud pit volume and thus reduce the false alarm rate of kick and lost circulation monitoring.Then,the kick and lost circulation monitoring model based on rule inference established in this paper is used to measure the impact of the risk-like trend of the mud pit volume on the kick and lost circulation monitoring.4,500 groups of drilling data measured on field were used to test the performance of the proposed models using the kick and lost circulation monitoring method based on rule inference.The results show that the false alarm rate of the risk monitoring method drops from 10.03%to 3.06%.