"三超"油气井的超深、超高温和超高压特点给井控装备配套和井控安全带来了严峻挑战,在钻井过程中发生井涌溢流的概率较大,需要对其井控技术难点及对策进行探讨分析。在给出"三超"油气井定义的基础上,介绍了国内典型"三超"油气井的钻井情况,论述了"三超"油气井在地层压力预测、井身结构优化设计、溢流监测与井底压力确定等方面存在的主要问题,从井控装备配套、提高套管强度和溢流早期监测等方面提出了技术对策,并结合"三超"油气井井控特征提出了一种动态变参数压井方法,即设计采用不同密度的压井液进行压井,压井过程中动态调整压井液排量、分段泵入不同密度的压井液,实现套压的快速降低,提高一次压井成功率。研究结果为今后"三超"油气井的井控关键技术研究及井控装备配套提供了技术参考。
Oil and gas wells that are ultra-deep and have ultra-high temperature and pressure pose significant challenges on wellhead equipment,well control and other operational and safety aspects.Since the drilling of such wells may involve a high probability of gas kicks during drilling and the potential for a catastrophic blowout,it is necessary to review the technical challenges posed in well control and to highlight relevant countermeasures.In addition to specifying a definition for wells with ultra-depth,ultra-high temperature and pressure,this paper reviews conditions of typical wells in the global settings.In addition,the paper provides a study on key challenges of such wells in formation pressure prediction,casing program optimization,overflow monitoring and bottom-hole pressure determination.Further,the paper highlights technical solutions for necessary well-control facilities,the enhancement of casing strength,and the early monitoring of overflows.In addition,an innovative well-killing technique involving dynamic variable parameters was proposed that incorporates specific features in well control for such wells.According to the design,well-kill operations can be performed by using killing fluids with various densities.Further,the flow rates of killing fluids can be adjusted in accordance with specific requirements.In this way,killing fluids with different densities can be used at different intervals to effectively reduce casing pressures and to dramatically enhance success rates for killing operations in one-operation.Relevant research results may provide necessary technical references in the development of key well control techniques and the deployment of necessary facilities in well control operations in ultra-deep wells with ultra-high pressures and temperatures.