硬顶法压井技术在渤海油田的应用

Application of Hard-Top Well Killing Technology in Bohai Oilfield

【目的】海上油田钻井作业面临的地质条件、井下工况日趋复杂,部分井无法采用常规的压井方法实施压井,不仅增加了作业工期,而且可能形成井控风险。为了实现渤海油田复杂井安全压井,避免井控事故发生,在渤海油田应用了硬顶法压井技术。【方法】针对渤海油田的特殊工况,分析硬顶法压井技术适用的工况,指出硬顶法压井技术相关计算原则。通过分析硬顶法压井应用实例,提出该技术应用时的注意事项。【结果】研究结果表明,硬顶法压井技术适用于关井钻头离井底远、地层含有毒有害气体、钻具或钻头水眼堵塞、关井后发生井漏导致喷漏同存、长裸眼段测试后压井等五个方面,计算原则可从压井液密度计算、压井排量选择和过程计算等三个方面考虑。针对该技术在渤海油田A井的应用实例,提出了井口关键设备耐压等级的确定、上层套管鞋处地层承压能力、设备的选择、薄弱地层的处理四个方面需要注意的事项。【结论】研究结果明确了硬顶法压井技术使用原则和注意事项,可为硬顶法压井技术在复杂海上油田应用提供技术支持与参考。

[Purposes]The geological and downhole conditions faced by offshore oilfield drilling operations are becoming increasingly complex,and some wells cannot be killed using conventional well killing methods,which not only increases the operation period,but also may create well control risks.In order to achieve safe well killing of complex wells in Bohai Oilfield and avoid well control accidents,the hard top well killing technology has been applied in Bohai Oilfield.[Methods]The applicable working conditions of hard top well killing technology were analyzed in response to the special working conditions of Bohai Oilfield.The relevant calculation principles of hard top well killing technology were pointed out.By analyzing the application examples of hard top well killing technology,the precautions for the application of this technology were proposed.[Findings]The results indicate that the hard-top method of well killing technology is suitable for five aspects:the shut in drill bit is far from the bottom of the well,the formation contains toxic and harmful gases,the drilling tool or drill bit is blocked in the water hole,the leakage occurs after the well is shut in,and the well is killed after long open hole testing.The calculation principles can be considered from three aspects:the calculation of well killing fluid density,the selection of well killing displacement,and process calculation.Based on the application example of this technology in Well A of Bohai Oilfield,four aspects that need to be noted are proposed:determining and clarifying the pressure resistance level of key equipment at the wellhead,determining the pressure bearing capacity of the formation at the upper casing shoe,selecting equipment,and handling weak formations.[Conclu sions]The research results clarify the principles and precautions for the use of hard top well killing tech nology,providing technical support and reference for the application of hard top well killing technology in complex offshore oil fields.