塔里木博孜区块巨厚砾石层气体钻井实践与认识

PRACTICE AND UNDERSTANDING OF GAS DRILLING IN HUGE THICK GRAVEL LAYER IN TARIM OILFIELD BZ BLOCK

塔里木博孜区块沉积巨厚砾石层,机械钻速低、钻头耗用多、钻井周期长是该区块勘探开发提速的一大瓶颈。通过砾石层气体钻井井壁稳定性、防斜打快、沉砂控制及钻井液转换等可行性研究,筛选出适合气体钻井层段,运用阀式连续循环、预弯钟摆钻具组合、气液转换等关键技术,开展了3井次现场应用实践,取得了较好的提速效果,同比钻井液钻井,行程钻速平均提高3.4倍,节省钻头7只以上,单只钻头进尺平均提高3.5倍,初步形成了博孜区块砾石层气体钻井配套工艺技术。

In BZ block of Tarim basin,huge thick gravel layer is deposited with such challenges influencing the accelerating exploration and development in this block as low ROP,much more drill bit consumption and long drilling cycle.Through the feasibility researches on wellbore stability,inclining prevention and rapid drilling,sand settling control and drilling fluid conversion in gas drilling in such thick gravel layer,such key technologies suitable for gas drilling have been selected as valve type continuous circulation,pre-bending pendulum BHA and gas-liquid conversion.Gas drilling has been carried out in 3 wells in BZ block with good speeding up results.Compared with the drilling fluid drilling,the average ROP of the trip in gas drilling is increased by 3.4 times,more than 7 bits are saved,and the average footage of a single bit is increased by 3.5 times.