顺北油气田火成岩侵入体覆盖区超深井优快钻井技术

Ultra-Deep Well Drilling Technology in the Igneous Invasion Coverage Area of the Shunbei Oil and Gas Field

顺北油气田火成岩侵入体覆盖区超深井钻井时,既存在二叠系火成岩井漏、志留系泥岩垮塌和古生界深部地层可钻性差等问题,还存在因火成岩侵入体地层坍塌压力高带来的钻井难题。前期,该油气田为了解决火成岩侵入体覆盖区超深井井眼垮塌的问题,提高了钻井液密度,并对火成岩侵入体进行了专封,但效果较差,而且超深井完钻井眼直径仅为120.7 mm,定向工具故障率高,导致钻井效率较低。为此,建立了地层三压力剖面,分析了钻井必封点及套管序列,优化了火成岩侵入体覆盖区超深井井身结构,将完钻井眼直径由120.7 mm增大为143.9 mm,并研究应用了二叠系防漏技术、志留系井壁稳定技术、火成岩侵入体安全钻井技术及分层钻井提速技术,形成了顺北油气田火成岩侵入体覆盖区超深井优快钻井技术。该优快钻井技术在7口超深井中进行了现场应用,钻井周期大幅缩短,机械钻速明显提高,表明其可以解决现场施工存在的技术难题,具有推广应用价值。

When drilling ultra-deep wells in the igneous invasion area of the Shunbei Oil and Gas Field,challenges such as lost circulation in the Permian igneous rock,borehole collapse in the Silurian mudstone and poor drillability in deep Paleozoic strata are commonly encountered.In addition,the large collapse pressure of igneous invasion layer also brings new drilling problems.Previously,this oil and gas field tried to increase the drilling fluid density to alleviate the borehole collapse in igneous invasion and optimize the casing program design to specifically seal the igneous invasion,but the effect was limited.The size of completion borehole is only 120.7 mm,and the failure rate of directional drilling tools is high,which leads to low drilling efficiency.In order to solve the above-mentioned common problems and new problems in the ultra-deep well drilling of this area,a formation tri-pressure profile was established,the necessary sealing points and casing sequence were analyzed,and the original completion borehole size was expanded from ?120.7 mm to ?143.9 mm,hence optimizing the casing program in the igneous invasion coverage area.The Permian leakage prevention technology,the Silurian borehole stabilization technology,igneous invasion safety drilling technology and zonal drilling acceleration technology were developed and integrated into the ultra-deep well drilling technology for rock invasion coverage area of the Shunbei Oil and Gas Field.This integrated technology was successfully applied in 7 ultra-deep wells,which reduced the drilling cycle significantly and improved the ROP largely,indicating that it could solve practical problems properly and is of significant application value.