In Samaraneftegas JSC more than half of operational wells are difficult. Most of the fields have passed to the final stage of development. The factors that complicate the operation of wells include free gas at the pump reception, the presence of mechanical impurities, scaling, asphalt-resin-paraffin deposits, abundant liquid absorption, curvature of the wellbore, low reservoir pressures, etc. In this regard, the urgent task is to find new technologies, technical solutions and equipment which can reduce the time of repair works, increase the efficiency geological and engineering operations, enhance oil production, and reduce financial expenditure.
The article discusses the complications, modern equipment and methods of work when cleaning wells from mechanical impurities in conditions of low reservoir pressures, and abundant absorption of washing liquid. In order to increase the efficiency of the bottomhole zone cleaning, an analysis of the existing technologies in the market has been carried out at Samaraneftegas JSC. The main criteria for the search for technology were a low risk of accidents, flushing for one tripping operation an interval of at least 30 m in length from proppant and quartz sand, as well as the possibility of circulating in wells with absorption of flushing fluid. To carry out pilot field tests, a well washing technology was selected using a sliding wash device and special jetting pen allowing effectively destroy the proppant or sand plug. The flushing device was successfully tested. In wells with a significant absorption, the loss of flushing fluid is reduced by 3-4 times compared with the losses during direct flushing. Rinsing using this technology in well No. 12 of Evgenievskoye field provided minimal loss of flushing fluid and allowed to clean the bottomhole zone from the proppant plug after hydraulic fracturing.
References
1. Obidnov V.B. et al., Features of proppant plug removal from gas condensate well upon completion of hydraulic fracturing of formation (In Russ.), Problemy sbora, podgotovki i transporta nefti i nefteproduktov, 2009, no. 2, pp. 48–51.
2. Dmitruk V.V., Peculiarities of bottom hole washing from proppant plugs after hydraulic fracturing (In Russ.), Nauka i tekhnika v gazovoy promyshlennosti, 2012, no. 3, pp. 47–52.
3. Amirov A.D. et al., Kapital'nyy remont neftyanykh i gazovykh skvazhin (Workover of oil and gas wells), Moscow Nedra Publ., 1975, 344 p.
4. Patent no. 2405914 RF, Method and device for well flushing, Inventors: Nagumanov M.M., Aminev M.Kh., Shaykhutdinov M.M.
