The Development and Properties of an Environmentally Friendly Metal Friction Reducer for Coiled Tubing

An environmentally friendly oil in water (O/W) metal friction reducer has been developed to address the locking problem encountered in coiled tubing operation in a horizontal well with long horizontal sections. The metal friction reducer was made from several core reactants such as a modified vegetable oil, a surfactant and ethylene glycol. Laboratory experiment was conducted to study the effect of the friction reducer on the coefficient of friction (CoF) of N80, P110 and Cr-13 steels at different concentrations, salinities, pH values and temperatures. The effect of the friction reducer on the environment was also studied through MTT experiment and animal test. It was found that at concentration of 0.5%, the friction reducer performed at its best. At this concentration of the friction reducer, the CoF of N80 steel was reduced from 0.42 (tested with water and N80 steel) to 0.12, or a percent reduction in CoF of 71.4%, the CoF of P110 steel was reduced from 0.475 (tested with water and P110 steel) to 0.16, or a percent reduction in CoF of 66.3%, the CoF of Cr-13 steel was reduced from 0.75 (tested with water and Cr-13 steel) to 0.115, or a percent reduction in CoF of 84.7%. The metal friction reducer can be used at 140 ℃, in a pH range of 1-10, and can tolerate salinity up to 30,000 mg/L. The metal friction reducer has cell proliferation rate between 95% and 150%, and LC₅₀ of about 55,000 mg/L, indicating that the it has no toxicity to cells and animals. The metal friction reducer has excellent friction reduction performance and can satisfy the needs of field coiled tubing operation.