The Research On The Mechanics Analysis For Casing Of Ocean Thermal Recovery Wells

In recent years, large-scale mining for heavy oil of offshore field is happening using the way of thermal recovery, the working conditions of downhole completion string is very bad by the method of thermal recovery, it is easy to occur the yield stress and fatigue, resulting in well completion string damage. At present, the domestic study for well completion string failure problem is many, but it still did not achieve the desired effect. Therefore, carrying out the research for well completion string mechanics analysis of thermal recovery wells in offshore field can help to reveal the string damage mechanism, take targeted measures, in order to prolong the life of thermal recovery wells, promote efficient development of heavy oil in offshore field.This paper investigated the damage types of well completion string, analyzed the damage mechanism, and studied the relationship between damage mechanism and damage form from the analysis for damage situation of thermal recovery wells.The temperature field analysis model for thermal recovery wells was established, the influence law of temperature on the strength of well completion string was analyzed, the mechanics analysis for the completion string under normal temperature state and warming state was carried out, a set of stress analysis method for well completion string in thermal recovery wells was established considering the influence of the injected steam temperature; the simulation analysis for casing stress was carried out using finite element software, and further verified the mechanism of casing damage, and put forward several measures to prevent completion string damage.This paper focused on the damage problem for well completion string of offshore thermal recovery wells,and studied the stress distribution for well completion string in thermal recovery wells,and furtherly clarified the damage mechanism of casing, and put forward the corresponding prevention measures,it provided scientific technical reference for selection of casing and designing of injection construction parameter in the thermal recovery wells of offshore field.