Analysis Of The Reason Of Casing Wear And The Research Of New Technology About Big Repair Of Casing In Huanxi Oil Field

With many yeas of development in Huanxi oil field, especially after polycyclic steam stimulation of heavy oil, Huanxi oil field is now in the middle and late stage of development, the status of old wells become worse and worse. Therefore, it plays great roles to master present situation about casing wear in Huanxi oil field, analyze rules of casing wear and summarize the law, thus we may find a new effective way or more to solve casing repair.Based on statistic of more than 2000 wells in Huanxi oil filed, this paper has summarized the law of casing wears,explored main damage to casing wear. It has shown the major contradictory is that: change of hot casing caused by steam injection, change of reservoir stress caused by formation sand flow, uneven cement job quality, reservoir stress concentration within the inner parts of casing and many other factors. The paper proposes the application of casing plastic subsidies technology, casing plastic reinforced sand control, windows reinforced sand control technology for different geological conditions, different sets of damage well, casing damage in different parts and different degree of damage, which is strong supplement of big repair of casing and forceful technology guarantee for the restoration of cut-off and difficult wells, while cost-saving. The research and practice show that: Huanxi oil field has both applied casing plastic subsidies technology, sand plastic reinforced sand control technology, windows reinforced sand control technology and recover casing failure shut-in well to improve well efficiency and increase oil product obviously, now 21 casing-wear shut–in wells have been restored. So far, Huanxi oil field has increased oil 29517t additionally. Implementation of new technologies of casing repair may not only restore well productivity, but also maintain sand control and extend well pump inspection cycle. 13 wells which apply sand plastic reinforced sand control technology, windows reinforced sand control technology have shown obvious sand control effect and has the average check period extended to 68d. Those wells using traditional sidetrack drilling restoring technology cost $600 000 per well, while the cost decline to $320 000 per well after the application of new technology. We acknowledge that not only the shrinkage of repair time, but also saving of cost by $280 000 per well by the application. Thus, the technology is an effective casing-repairing technology for Huanxi oil field.