Study On Plugging Removal Technology Of YB High-pressure And High-sulfur Gas Wells

The high sulphur gas reservoir has been developed for many years,but there are obvious deficiencies in the understanding of the movement of sulfur in the wellbore and the law of dissolving in the natural gas,the protection and corrosion detection of the gas tree,the monitoring of the wellbore,the wellhead control cabinet and the maintenance as well as maintenance.Based on the Guangyuan gas reservoir,the problems of wellbore plugging and two-phase flow were systematically studied,and the pressure of the annular belt was analyzed,The main studied work and conclusions are as follows:(1)The measured data were fiited and analyzed using seven kinds of wellbore flow models,and the models of Parameter 1 and Paramter 2 were corrected.The error analysis shows that Paramter 2 model is the best and its average error is only 0.16%,which is suitable for the engineering calculation.(2)The calculation method of pressure and temperature coupling in the wellbore was determined,and the pressure and temperature distribution in the wellbore were calculated.(3)The abnormal changes of the oil pressure in the well 205-1 of the Guangyuan gas reservoir were analyzed together with sulphur deposition,hydrate blockage,well bore impurity blockage,and seating ball.It was found that the blockage of well bore in well 205-1 was caused by formation rock particles,fluid residue after fracturing,sulfur deposition and steel ball blockage.Three schemes of active acid plugging,sulfur solution plugging and continuous tubing dissolving were put forward,and well tests were carried out.The results show that the effective acid plugging effect is better,and the oil pressure and gas production can be recovered temporarily,and the effective period is about 30 days.(4)The hydrate formation and inhibitor screening experiments were carried out.The formation temperature and pressure of 14 groups of hydrate were measured.The formation temperature of hydrate at different concentrations of 9 groups of methanol and ethylene glycol was determined under two pressures.The methanol stood out as YB gas field's hydration inhibitor.Based on the analysis of the well hydrate of Yuanba 103H well,the prevention of high-sulfur and high-production gas wells and hydrates in the YB gas field were proposed.We systematically obtained the law of the change of the two phase flow and pressure in the well bore of Guangyuan high sulphur gas well,the mechanism of wellbore plugging and corrosion,and further understood the characteristics of the existing gas production technology in the high sulphur gas well,and proposed the technical countermeasures to solve the gas well clogging and corrosion,which will promote the effective and safe exploitation of the Guangyuan high sulphur gas reservoir.