Application of stray current discharge protection technique to electric pump oil wells

Through scanning the pitted leak casing in the electron microscope, we find that the galvanic corrosion and the electro-chemical corrosion lead to the casing leak of the electric pump oil wells in the transition terrain region north of Sabei oil field. To reduce the corrosion rate, we take the measures of the isolating direct current discharge protection and the negative electric potential discharge protection. Application of the discharge protection shows that the change scope of the casing-ground electric potential fluctuation reduces from 124.0 mV to 27.1 mV. The casing-ground electric potential is from -(0.56) V (Cu/CuSO_4) excursion to -0.85 V(Cu/CuSO_4), and the protection rate reaches 78.1%. The combined discharge protection method is worth generalization.