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牛东1井勘探取得重大突破,测试折算日产天然气56.2558×104m3、日产油642.91m3,坚定加快了渤海湾盆地超深潜山内幕勘探步伐。但超深井钻井周期长、投资成本大、风险高,迫切需求钻井提速技术来技撑。牛东区块潜山油气藏埋藏深,地层岩性变化大,压实程度高,岩石研磨性强,可钻性差,钻头磨损快,起下钻频繁,机械钻速慢,钻井周期长,严重制约勘探评价一体化进程。实钻表明:为了提高该区块钻井速度,通过对牛东1井声波时差测井数据和岩心室内可钻性试验分析,对PDC钻头崩齿和磨损进行机理研究,联合钻头厂家在邻井钻头基础上,优化布齿密度、改变切削齿直径、增加复合片强度,提高PDC钻头攻击性和破岩能力;调整钻头切削齿后角设计、强化钻头保径磨损、减小钻头井底受力不平衡振动磨损,增加钻头工作时间,延长钻头行程;模似钻头井底流场形态,优化排屑槽、流道设计,冷却钻头,提高携岩效率,清洗井眼,降低井下复杂风险。通过现场应用,成效显著,为今后该区块个性化PDC钻头选型提供了参考价值。
Exploration of NiuDong 1 well has made a major breakthrough. The test converted 56.2558 × 104m3 of natural gas and 642.91m3 of daily production oil, which steadily accelerated the exploration of the ultra-deep buried hill in the Bohai Bay Basin. However, the ultra-deep well has long drilling cycle, high investment cost, high risk and urgently needs drilling speed-raising technology. The buried hill reservoir of Niudong block is buried deeply, the lithology of formation changes greatly, the degree of compaction is high, the grindability of rock is poor, the drillability of drill bit is poor, the drill bit is worn fast, the drilling time is low, the drilling speed is slow, the drilling cycle is long, Exploration evaluation integration process. The actual drilling shows that in order to improve the drilling speed in this block, the mechanism of PDC bit breaking and wearing is studied through the acoustic time difference logging data and core indoor drillability test in Niudong 1, On the basis of optimizing the density of cloth teeth, changing the diameter of cutting teeth, increasing the strength of the composite sheet and improving the aggressiveness and rock breaking ability of the PDC bit; adjusting the relief angle design of the cutting teeth of the bit to strengthen the wear of the bit and reduce the stress on the bottom of the bit Balance the vibration and wear, increase the bit working time and prolong the bit travel; simulate the shape of the bottom flow field of the bit, optimize the chip flute and runner design, cool down the drill bit, increase the rock carrying efficiency, clean the borehole and reduce the complex risk in the well. Through the field application, the result is remarkable, which provides a reference value for the personalized PDC bit selection in the future.