深水“一体化”保温测试液体系研究与性能评价

Study and Performance Evaluation of an “Integrated” Insulation Test Fluid Using in Deep-water Well Test

针对国内深水单层隔水管柱测试作业具有隔热性差、上部隔水管环空与下部油套环空连通会影响测试性和传压性等特点,研制了由合成多元醇与还原糖醇复配而成的低导热系数非水基液“一体化”保温测试液。并对该保温测试液进行了导热性、密度可调性、可泵性、流变性等性能的评价,实验结果表明,该测试液抗温可达150℃,导热系数为0.2428~0.2866W/(mK),密度能在1.05~1.50g/cm^3或者1.50~1.05g/cm^3间由低到高或由高到低调节,150℃静止15d的沉降降因子为0.50,25℃下表观黏度不大于70mPas,4℃下静切力不大于3Pa,具有较好的传压性,150℃下的3d平均腐蚀速率为0.0369~0.0690mm/a,岩心渗透率恢复值达95%以上;另外该保温测试液不仅环境友好,含油量为零,能满足GB18420.12009《海洋石油勘探开发污染物生物毒性第1部分:分级》标准中一级海域使用要求,而且还可回收再利用,可大大节约测试成本。可以用于深水单层隔水管测试作业。

An “integrated” insulation test fluid has been formulated with a synthesized polyol and a reducing sugar alcohol to address problems encountered in testing deep-water wells with single-layered riser,such as poor heat insulation,connection of the annulus of the upper riser and the annulus of the lower production string,which affects well testing and pressure transmission,etc.The “integrated” insulation test fluid is a non-aqueous fluid with low heat conductivity.Laboratory evaluation on the heat conductance,density adjustability,pumpability and rheology of the test fluid shows that this test fluid has the following properties: temperature resistance of up to 150 ℃,heat conductivity of 0.2428–0.2866 W/(m·K),density adjustable between 1.05 g/cm^3 and 1.50 g/cm^3,settlement factor of 0.50 after standing still for 15 d,apparent viscosity at 25 ℃ of 70 mPa·s at most,gel strength at 4 ℃ of 3 Pa at most,good pressure transmission,average corrosion rate in 3 d at 150 ℃ of 0.0369–0.0690 mm/a,and percent core permeability recovery of at least 95%.Furthermore,this test fluid is environmentally friendly,and has no oil in it.It satisfies the Class 1 requirements of offshore application in accordance with the standard “Biological toxicity for pollutants from marine petroleum exploration and exploitation–Part 1: Grading”.This test fluid can be recovered for reuse,greatly reducing operational cost.It can be used in testing deep water wells with single-layered riser.