Oil well killing during workover operations in complicated conditions
Mardashov D.V.1, Rogachev M.K.2
1 Federal State Budgetary Educational Institution of Higher Education “St. Petersburg Mining University”: Mardashov_DV@pers.spmi.ru
2 Federal State Budgetary Educational Institution of Higher Education “Ufa State Petroleum Technical University”
Well killing of the production wells before workover operations in final-stage oil and gas-condensate field’s production can be complicated by abnormally low formation pressure, carbonate type of reservoir rocks and high gas-oil ratio. These issues lead to the intensive absorption of technological fluids by the formation and gas ingresses, which increases the time of killing wells and putting them on production, reduction of productivity and additional OPEX. Therefore, it is crucial to develop a high-performance well-killing compositions that would allow improving the efficiency of killing wells in complicated geological, physical and technological conditions. Laboratory and methodological complex for physical modeling of oil well killing operation was created at the Mining University in order to develop new technological fluids for well killing operation. Using this complex, a number of blocking emulsion and polymer fluids for well killing operation have been developed, ensuring the preservation of filtration characteristics of the bottomhole formation zone with various types of reservoir rocks. The results of field tests of the developed killing technologies have shown technological efficiency in the form of an increase in the flow rates of oil, a reduction in the timing of their commissioning, as well as a reduction in the water content of the produced fluids.
Keywords: workover operations, well killing operation, well killing fluid, takeover, abnormally low reservoir pressure
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