耐高温高盐钻井液润滑剂的研制与性能评价

针对深井超深井钻井过程中高扭矩和高摩阻等难题，利用硼酸、多元醇和长链脂肪酸等原料，合成出一种耐高温高盐钻井液润滑剂SOB，该润滑剂在高温高盐条件下具有良好的润滑性能。在5%基浆中加入1%润滑剂SOB后，润滑系数降低率为92.7%，泥饼的黏附系数降低至0.0405，极压润滑持效性强；210 ℃下润滑系数降低率保持在90.2%，210 ℃、35%NaCl条件下润滑系数降低率保持在81.3%。高温高盐条件下SOB在高密度钻井液中配伍性良好，200 ℃老化后对钻井液的流变性无影响，能够降低钻井液滤失量，润滑系数降低率为45.09%，相比常规润滑剂性能优越，这是由于润滑剂能够在钻具表面有效吸附，形成一层疏水性较强的膜，使钻具与井壁的直接接触变成了润滑膜之间的接触，从而降低摩擦。 

Development and Performance Evaluation of High Temperature Salt Resistant Drilling Lubricant

Using boric acid, polyols and long-chain fatty acids, a high temperature salt resistant drilling lubricant SOB has been developed to deal with high torque high friction encountered in deep and ultra-deep well drilling. SOB has good lubricity at high temperatures and high salinities. A 5% base mud treated with 1% SOB has its friction coefficient reduced by 92.7%, and the adhesion coefficient of the mud cake produced by that mud is reduced to 0.0405, meaning that SOB has a sustainable lubricity under extreme pressure condition. Percent reduction of friction coefficient at 210 ℃ is generally 90.2%, percent reduction of friction coefficient of a mud containing 35%NaCl at 210 ℃ is generally 81.3%. At high temperature and high salinity conditions, SOB has good compatibility with other components of a high density drilling fluid. After aging at 200 ℃, the rheology of the drilling fluid was not affected, the mud filtration rate can be reduced, and the coefficient of friction of the mud was reduced by 45.09%, meaning that SOB has better lubricity than conventional drilling lubricants. The reason for this phenomenon is that SOB can be effectively adsorbed on the surfaces of the drill strings, forming a layer of film with strong hydrophobicity. The existence of this film changes the direct contact between the drill strings and the borehole wall to a contact between two films of the lubricant, thereby effectively reducing the friction therebetween.