Abstract A method of treating an earth formation, especially a calcareous earth formation, containing petroleum and connate brine to stimulate production of the petroleum without substantially increasing the production of brine. A liquid pre-flush composition, including a water solution of polar solvent having dissolved in the solution rosin soap and fatty acid soap is injected into the formation. The preflush composition reacts with the connate brine to produce a precipitate that blocks the brinebearing passages, but the preflush composition does not react with the petroleum to produce a precipitate. Thus, the petroleum bearing passages are left open. Thereafter, an acid solution or other treating solution is injected into the formation to selectively stimulate or treat the oil-bearing passages. Preflush concentrates and compositions for use in the formation-treating method are disclosed as well as processes of making such compositions.
A method of treating an earth formation containing petroleum and connate brine, the formation being in communication with a well, which comprises: a. introducing into the well a liquId preflush composition comprising a solution of a polar solvent in water having dissolved therein rosin soap and fatty acid soap; b. forcing said preflush composition into the formation to react with the brine and produce a pore-sealing precipitate; c. introducing into the well a formation-treating solution; and d. forcing said formation-treating solution into the formation.
Claim 2
Independent Claim
84 words
A method of treating an earth formation containing petroleum and connate brine, the formation being in communication with a well, which comprises: a. introducing into the well a liquId preflush composition comprising a solution of a polar solvent in water having dissolved therein rosin soap and fatty acid soap; b. forcing said preflush composition into the formation to react with the brine and produce a pore-sealing precipitate; c. introducing into the well a formation-treating solution; and d. forcing said formation-treating solution into the formation.
Claim 3
Independent Claim
84 words
A method of acidizing an earth formation containing petroleum and connate brine, the formation being in communication with a well, which comprises: a. introducing into the well a liquid preflush composition comprising a solution of a polar solvent in water having dissolved therein rosin soap and fatty acid soap; b. forcing said preflush composition into the formation to react with the brine and produce a pore-sealing precipitate; c. introducing into the well a formation-acidizing solution; and d. forcing said formation-acidizing solution into the formation.
Claim 4
Independent Claim
84 words
A method of acidizing an earth formation containing petroleum and connate brine, the formation being in communication with a well, which comprises: a. introducing into the well a liquid preflush composition comprising a solution of a polar solvent in water having dissolved therein rosin soap and fatty acid soap; b. forcing said preflush composition into the formation to react with the brine and produce a pore-sealing precipitate; c. introducing into the well a formation-acidizing solution; and d. forcing said formation-acidizing solution into the formation.
Claim 5
Dependent Claim
52 words
A method as defined in claim 2 wherein said polar solvent is an aliphatic alcohol containing from one to three carbon atoms, and said rosin soap and said fatty acid soap are selected from the group consisting of ammonium, alkali metal, lower amine, and urea soaps of rosin acids and fatty acids.