一种鸡蛋壳地层穿刺监测与预警结构及其作业方法

A Structure of Monitoring and Early Warning for the Puncture in Egg Shell Layers and Its Operation Methods

为了解决自升式钻井平台插桩遇“鸡蛋壳”地层发生穿刺导致船体失稳这一世界性难题,中国海洋石油工程技术人员创新性地提出了一种鸡蛋壳地层穿刺监测与预警结构及其作业方法。针对自升式钻井平台在南海多个油田的复杂地层插桩发生穿刺、桩基失稳等情况,通过在自升式钻井平台桩腿桁架上加装静力触探结构,在桩靴底部进行CPT试验,记录桩靴以下包含鸡蛋壳层段在内的地层参数,定量分析穿刺发生的可能性,从而对可能发生的穿刺提出预警,及时对就位插桩作业做出调整。数值模拟计算结果表明,该结构与作业方法可靠有效,对理论计算存在穿刺的地层进行了准确的监测与预警,有效避免了穿刺的发生,对插桩安全控制起到了积极作用,提高了海上大型设备安全。

In order to solve the worldwide problem of hull instability due to the puncture by the jack-up drilling platform plugging in"egg shell"formations,engineers in CNOOC innovatively proposed a structure for monitoring and early warning and its operation methods.Aiming at the puncture and the instability of the leg foundation of the jack-up drilling platform in the complex formations in multiple oil fields of South China Sea,CPT test is carried out at the bottom of pile shoe by installing CPT structure on the leg truss of the jack-up drilling platform.The formation parameters including egg shell layer under pile shoe are recorded.Through the stratum parameter processing system,engineers can quantitatively analyze the possibility of the puncture,so as to provide early warning for the possible puncture and make timely adjustments to the in-place plugging operation.The result of numerical simulation shows that the structure and the operation method are reliable and effective,which can accurately monitor and warn the stratum with punctures in theoretical calculation,and effectively avoid the occurrence of punctures.It also plays a positive role in the safe control of plugging and improves the safety of the large offshore equipment.