Research on Sulfosalt Multipolymer High Temperature Seawater Base Drilling Fluid

摘要

There are many formations and complex lithology in the Dagang Binhai block. Bottom hole temperature of ex ploration wells can reach up to 180℃. Problems such as circulation loss,hole instability and sticking are com mon. Maintenance of high temperature drilling fluids is very difficult. It requires the performance of the drilling flu id to be stable and anti -high -temperature. Through research on high temperature drilling fluids in the Dagang Binhai block and anti -high — temperature performance of sulfosalt multipolymer DSP, we developed a new type of 200℃ high temperature resistance seawater base drilling fluid through optimizing the fluid loss additive and high temperature inhibiter and high temperature blocking agent and low permeation lubricant. This type of fluid has a good rheological property at 200℃ and meets Bingham model of plastic fluid under different density and adjusta ble property and has a good thermostat ability. It also has good rejection capability and lubricant,anti NaCl,8. 0 × 104mg/l,anti Ca2+,5. 0 × 103mg/l,and the resiliency of core permeability reaches to 88. 17%; the depth of filter invasion is less than 1 cm. It represents a good performance when used in the BH8 well high temperature sec tion. It meets safe and fast drilling requirements for the Dagang Binhai block.