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

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/cm³ and 1.50 g/cm³, 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.