应用综合录井技术监测泥岩段井壁稳定性探讨

Discussion on wellbore stability by using comprehensive mud logging technique to monitor mudstone sections

在钻探泥岩井段过程中,往往会因泥岩吸水膨胀而造成井径缩小或泥岩裂解,导致井壁失稳,引发卡钻等工程事故。由于不能利用综合录井所采集的泵压、钻井液流量、出入口密度、出入口温度、钻井液池体积等参数提前判断井壁稳定情况,且独立的某个参数很难准确、客观地反映钻井状态,多录井参数的综合应用成为必然。通过采集现场录井、随钻或测井参数,应用GW-MLE综合录井仪后台软件进行环空水力学和地层压力实时计算分析,并综合分析气测、地质等多种参数可以判断井壁稳定情况,进而实现对泥岩段井壁稳定性的监测。现场钻井事故实时监测数据验证了上述方法的可行性,表明应用综合录井技术能在工程事故发生前向建设方及时提示井壁稳定性异常显示,以便及时采取措施保障钻井施工安全,从而达到提高勘探开发整体效益的目的。

In the course of drilling mudstone section,well caliper reducing or shale cracking which are often caused by mud water absorbing and swelling can lead wellbore instability and then cause of pipe stuck and other construction accidents.Since the parameters collected by comprehensive mud logging,such as pump pressure,drilling fluid flow,outlet and inlet densities,outlet and inlet temperatures and pit volume can not be used to determine the borehole stability situations in advance,and a certain independent parameter is difficult to accurately and objectively reflect the drilling state,the comprehensive application of multi-logging parameters becomes inevitable.By collecting on-site mud logging,while drilling or wireline logging parameters,annular flow dynamics and formation pressure real-time calculation and analysis can be carried out by using GW-MLE comprehensive mud logging background software and the wall stabilizing situation may be determined by comprehensive analysis of various parameters of gas logging and geology and thus wellbore stability monitoring for mudstone sections can be realized.The feasibility of the method described above was verified by real-time monitoring of on-site data to the drilling accidents.It indicated that the application of comprehensive mud logging technology can prompt wellbore stability abnormal occurrence to the construction party before the accident to take prompt measures to ensure the safety of drilling operation,so as to improve the overall efficiency of exploration and development.