提切剂对合成基钻井液流变性的影响

Effects of rheological modifiers on rheological characteristics of synthetic base drilling fluid

对比分析不同温度下3种提切剂对全油/油包水合成基钻井液的提切效果及作用机制,模拟海洋深水钻井立管中低温、低流速条件,对比提切剂对油包水合成基钻井液黏温特性的影响,采用Haake RS300流变仪选用Rot模式测试不同提切剂配制的油包水钻井液的凝胶尖峰和流变曲线,选用Osc模式分析钻井液的弹性模量和黏性模量。结果表明,较高相对分子质量、具有多种极性基团的提切剂通过氢键形成弱凝胶,可提高低剪切速率下的黏度,改善油包水钻井液的触变性以及弹性模量,从而有效悬浮重晶石和清洗井眼。

The effectiveness of different rheological modifiers and their rheology control mechanisms in all and inverse drilling fluid systems under different temperatures were analyzed. By simulating the conditions of low temperature and low shear rate in offshore deepwater drilling operations, the effects of rheological modifiers on visciosity-temperature characteristics of syn- thetic base drilling fluid were compared. The gel peak, rheological curve, elastic modulus and viscous modulus were meas- ured through Haake RS300 rheometer for synthetic base mud with different modifiers. The results show that the rheological modifier SDMOD with high molecular weight and several polar groups can significantly increase the visciosity, rheopecticity and elastic modulus of oil based drillng fluid under low shear rate by forming fragile gel through hydrogen bond. Consequently, the invert emulsion drilling fluid can effectively suspend the barite and clean up the well.