Thermal-Pressure effects of multi-cycle carbon dioxide huff&puff and repeated stress damage:A theoretical approach to reducing casing deformation frequency
The research on the current casing deformation mechanism and its influencing factors in Jidong Oil Field has a large limitation,which makes the casing deformation evaluation unable to be quantified.In order to reduce the number of casing deformation,12 groups of laboratory uniaxial and triaxial tests are carried out based on the high temperature and high pressure multi-field coupling rock mechanics test system.Combined with ANSYS software,a three-dimensional geological model of casing-cement sheath-formation coupling is established.The influence of 5 factors on the rock and casing stress damage is analyzed,including sand production degree,cycle of huff and puff,perforation density,cementing quality and production time.The correlation with field data in Jidong Oil Field reaches 98.8%,and the reliability of the damage influencing factors is verified.The field test verification shows that the influence of carbon dioxide on rock strength under high temperature and high pressure is the main factor of casing deformation.It is suggested to improve the sand control accuracy,the number of cycles of stimulation shall not exceed 16,the hole density shall not exceed 12 holes/m,the casing strength shall be increased by 1～2 steel grades,and the cementing quality shall be improved to reduce the casing deformation probability.Through taking targeted prevention and control measures,the casing deformation degree of the research block is reduced by about 30%,the crack propagation speed is reduced by 25%,and the wellhead pressure fluctuation is reduced by 15%.The research results provide a new technical idea for the optimal design of construction parameters of carbon dioxide multi-cycle huff and puff.
Carbon dioxide huff and puffOil and gas resourcesUnconventional oil and gasIntegrity of wellboreEngineering TechnologyLaboratory testRock strength
万方数据
维普
