哥伦比亚中部山区Gigante油区深井钻井施工异常复杂，既存在山前构造常见的严重增斜现象，多套压力系统引起的井下复杂情况问题，严重井漏导致的易坍塌脆性泥页岩大范围剥落问题，微裂缝造成的钻井液高密度坍塌问题，又存在欠压实巨厚泥岩、伊蒙混层及构造应力等综合因素造成的井壁坍塌及泥页岩软硬交错地层形成密集犬牙导致的卡钻问题，还有因地应力、断裂带等原因导致的井璧不稳定及严重漏失问题，地温梯度异常（最高达42℃/1000 m），漏、塌、卡、喷难以预防，钻井施工异常困难。本文针对该油区深井钻井遇到的复杂情况，分析了地质成因及特点，详细论述了影响该区深井钻井速度的主要原因，并提出了解决措施与建议，对提高该区深井钻井速度、降低成本，缩短钻井周期，加快整个区块勘探开发速度具有重要意义。%The deep well drilling in Gigante oil province in the mountainous area of Columbia is extraordinarily complex. There are problems such as severe inclination within the piedmont structure, downhole troubles caused by several sets of pressure systems, the wide range of brittle shale collapse caused by severe lost circulation and the collapse due to high density drilling lfuid caused by micro cracks, wellbore collapse caused by the under-compacted thick mudstone, illite smectite mixed layer and the tectonic stress, and drill plpe sticking caused by soft-hard cross formations. There are also problems such as wellbore unstability caused by geostress and fracture belts and severe leakage, anomalous geothermal gradient(up to 42 °C/1 000 m), Thus it is extremely dififcult to perform drilling operatios because of severe lost circulation, collapse, stuckpipe and blowout. In view of the troubles encountered in deep well drilling in this oil province, this paper has analyzed the geologic origin and characteristics of this block, depicts the main factors which affect the drilling rate of deep wells and presents the solutions and suggestions, which have great signiifcance in improving deep well drilling rates,reducing drilling costs and drilling cycle and accelerating the exploration&developing rate of the entire block.
展开▼
