Determination Method for the Landing Depth of Coaxial Dual Hollow Rod

Coaxial hollow rod heating system is effective in solving the problem of wax deposition in borehole for high pour point oil well and high viscosity for heavy oil well.However,considering oil well production efficiency,cost and comprehensive economic benefit,it’s necessary to calculate the optimal landing depth of the sucker rod.Aiming at wellhead oil temperature optimum and taking sucker rod depth and circulating water inlet temperature as constraints,the wellhead oil temperature C(x,t)relation model was established.In the model,it first uses iterative method to optimize the landing depth of coaxial hollow rod and then checks the pumping load based on the optimization results.This model has been used in 13 oil wells instead of sucker rod depth estimation from experience.The effective rate increased by 14.1 percentage which meets the production needs and saves the cost of well development.