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水平井开发钻遇碳质泥岩和煤层段,煤层和碳质泥岩胶结疏松,新井眼钻开后地层应力被释放和水化膨胀分散,极易导致坍塌掉块形成大肚子井眼,造成蹩钻、起下钻阻卡甚至井眼报废等恶性事故。水平段钻遇不同程度的微裂缝,发生渗透性和失返性漏失引起井下复杂,导致钻井难以继续。采用具有防塌和防漏能力封堵型聚磺钻井液,并优选出了封堵型聚磺钻井液体系配方,该钻井液具有较强的防塌和防漏失能力,较强的润滑能力,能有效地提高钻井速度,同时提高储层保护性、改善钻井液流变性、钻井液抗污染性强,预防井下事故效果好。
In horizontal wells, carbonaceous mudstone and coal seams are drilled and the coal and carbonaceous mudstone are loosely cemented. After the new borehole is drilled, the formation stress is released and the hydration expands and disperses, which can easily lead to the collapse of the block and the formation of a big belly hole, From drilling resistance card or even borehole and other serious accidents scrapped. Drilling horizontal fractures to varying degrees of micro-cracks, the occurrence of permeability and loss of lost caused complex underground well, resulting in drilling difficult to continue. Using a plugging-type polysulfonic drilling fluid with anti-collapse and anti-leakage capabilities, and a plugging-type polysulfonic drilling fluid formulation is preferred. The drilling fluid has strong anti-collapse and leakage prevention capabilities, strong lubricating ability, It can effectively improve drilling speed, improve reservoir protection, improve drilling fluid rheology, strong anti-pollution of drilling fluid and prevent downhole accidents.