东海X区块钻井提速研究与应用

Research and application of faster drilling in Block X of East China Sea

东海X区块地层可钻性较差,导致机械钻速低、钻头进尺短、井眼浸泡时间长、钻具遇阻遇卡,钻井效率低下,在对区内历史井地层特性、岩石抗压强度及钻头使用情况等分析的基础上,开展了钻井提速研究。结果表明,钻头优化、使用复合冲击器、井身结构优化的配套系统性提速方案可提高钻井效率、缩短钻井周期、降低复杂情况、加快油气勘探进程。其中,根据复合冲击器的工作原理和寿命优化井眼轨迹,对钻头设计时使用中等抛物线、加强肩部布齿密度,可解决区内钻头磨损严重、单个钻头进尺少需3~4趟钻完成一个井段作业、深部地层平均机械钻速低于10 m/h等一系列难题。该提速方案现场应用,减少了卡钻、井眼垮塌等井下复杂情况,实现了各开次井眼一趟钻工程,缩短钻井周期6~8 d,并在该区块创下了单只钻头进尺和机械钻速等多项新记录,钻井效率明显提高,为东海油气勘探提速增效探索了一条可行的技术路线。

The poor formation drillability in Block X of East China Sea always leads to low penetration rate,short drill footage,long borehole immersion,and low drilling efficiency.Based on the analysis of the geological characteristics,rock compressive strength,and bit usage of historical wells in the block,a study on drilling speed improvement was carried out.The results indicate that the acceleration plan with optimized drill bits and wellbore structure,and compound impactors can improve drilling efficiency,shorten drilling cycles,reduce complexity,and accelerate the process of oil and gas exploration.According to the working principle and service life of the compound impactor,the well bore structure is optimized,the medium parabola is used in the design of the bit,and the tooth distribution density of the shoulder is strengthened,which solves the problems such as serious wear at individual positions,less than 3 to 4 trips per bit to complete a well section and an average ROP in deep formations less than 10 m/h.The on-site application of this acceleration plan has reduced complex downhole situations such as sticking and wellbore collapse,achieved one trip drilling for each well opening,and shortened the drilling cycle by 6-8 days.And then multiple new records such as single drill bit footage and mechanical drilling speed have been set in this block,greatly improving drilling efficiency and exploring a feasible technical way for increasing the speed and efficiency of oil and gas exploration in the East China Sea.