Production wells killing on R. Trebs high-temperature cavernous-fractured carbonate deposits

R. Trebs oil field is characterized by deep oil pay zones (3677-4144 m), multilayer complex structure and high temperature of about 93°C at the bottom. During development it is observed a significant reservoir pressure drop. Thus, the values of initial pressure differences between layers reached 5 MPa. Such factors along with high fracture carbonate reservoir leads to a large volume of killing fluid loss and the risk of gas shows during repairing the wells. Considering all these facts we chose the well killing technologies and pilot testing of them to reduce non-productive volumes of killing fluid and ensure reservoir protection fr om negative impact of aqueous solutions for specific geological and physical conditions of R. Trebs oil fields. It was justified the necessity of using blocking compounds on the basis of a temperature-stable invert emulsions and guar-based polymer systems. Based on research results we made the rating of blocking compounds wh ere together with their blocking properties we considered the possibility of forced destruction of installed pack, easy transportation, storage and preparation in field conditions, and fire and explosion safety. After ranging the compounds for pilot testing, we selected the technology using gel-forming reagent on guar basis and emulsifier to form invert water-oil emulsions. During the test we could prevent oil and gas shows, and eliminate unproductive consumption of well killing fluid. Data analysis was developed into recommendations for industrial application of the tested reagents for well killing at R. Trebs oil fields.

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