Increasing the production of gas condensate by using ammonium carbonate salts

Abstract

The work is devoted to the problem of increasing gas condensate production in gas condensate fields. It was found that ammonium carbonate salts, in the absence of calcium chloride type waters, interact with carbonate rocks, increase the permeability of reservoirs. Solutions of ammonium carbonate salts when interacting with formation water of the calcium chloride type form chemically precipitated chalk in the pore space, while the permeability of carbonate rocks decreases. A set of experimental studies was carried out to study the displacing and washing properties of ammonium carbonate salts. It was found that ammonium carbonate salts have high displacing properties, the displacement ratio of kerosene by NH4HCO3 solution is 0.75-0.80, while reservoir water – 0.55-0.58. According to the results of laboratory studies of the displacing and washing characteristics of ammonium carbonate salts, conclusions were made about the effect of bicarbonate solution (ammonium carbonate salts) on the production characteristics of a well in reservoir conditions at temperatures of 80-100 °C and above. Industrial tests of ammonium carbonate salts showed an increase in gas flow by 30-50% at wells № 23 of Opishnia, № 115 of Mashivka, № 3 of Tymofiivka gas condensate fields. The effect of formation treatment with ammonium carbonate salts is achieved due to clearing of well bottom zone and increasing the formation permeability. At wells № 56, 108 of Yablunivka and № 58 of Tymofiivka gas condensate fields, an increase in the condensate ratio was observed by 22-35%. The effectiveness of this treatment is associated with the simultaneous bottomhole zone cleaning from asphalt-resinous contaminants and permeability increase, as well as with the hydrophilization of the pore space and mobility increase of condensate precipitated as a result of carbon dioxide effect, which was rejected as a result of decomposition of ammonium carbonate. Thus, experimental and industrial tests in Opishnia, Mashivka, Tymofiivka, Yablunivka gas condensate fields of Poltava region confirmed the effectiveness of using ammonium carbonate to increase hydrocarbon production. The prospect of further research is aimed at developing a technology for increasing the production of liquid hydrocarbons by using ammonium carbonate salts.