Failure Analysis of Oil Tube Collapse in A Production Well in Tahe Oilfield
The 414th oil tube collapsed and failed in a production well in Tahe Oilfield in the process of acid fracturing and coiled oil tubing gas lift increase production.With the macroscopic morphology observation,wall thickness test,corrosion product characterization and collapse simulation calculation of the collapsed oil tube,the reason for the 414th oil tube collapsed was that the oxygen in the nitrogen injected during the coiled oil tubing gas lift process and the acid fluid in the acid fracturing process corrode the inner wall of the collapsed oil tube,which first lead to serious thinning of the inner wall of the oil tube,when the critical collapse pressure caused by its wall thickness reduction was less than the hydrostatic pressure which caused by the annulus protection fluid,the tube collapsed.It is suggested that the gas injection source of coiled oil tubing gas lift could be optimized when the production wells increase production under similar working conditions in the future,nitrogen with purity of 99.9％should be selected.And the acid fracturing process could be optimized to extend the acid fracturing time.
production welloil tubecollapsegas liftfailure analysis
万方数据
维普
