新型液体减轻剂在南海某深水井表层固井中的应用

Application of a New Liquid Weighting Agent in Surface Casing Cementing in Deepwater Well in the South China Sea

目前,我国海洋油气开采正迈入深水时代,但是深水区块普遍存在着泥线低温、表层松软易漏、易发生浅层流的特点。针对这些难点,通常在深水表层固井过程中使用低密度漂珠水泥浆体系,但是该体系存在着混配不均、容易破裂损失等缺点。因此,在南海西部某口深水高温高压井固井过程中,创新性地使用了一种新型的液体减轻剂配制的表层水泥浆——PC-LiquidLet水泥浆体系。现场使用结果表明,该水泥浆体系在低温条件下具有较高的早期强度发展、低失水和较好的流变性,能够很好地适用于南海西部海域表层固井作业。

Currently,China's offshore oil and gas exploitation is stepping into the deepwater era,but in deepwater blocks,there are generally characteristics of low-temperature mudlines,soft surface layers prone to leakage,and a propensity for shallow flow.To address these challenges,a low-density floating bead cement slurry system is usually used in the cementing process of deepwater surface layers,but this system has disadvantages such as uneven mixing and easy breakage and loss.Therefore,in the cementing process of a deepwater high-temperature high-pressure well in the western part of the South China Sea,an innovative new type of liquid weighting agent formulated surface cement slurry—PC-LiquidLet cement slurry system—was used.Field use results show that this cement slurry system,under low-temperature conditions,has a higher early strength development,low fluid loss,and good rheology,and is well suited for surface casing cementing operations in the western South China Sea.