Prevention of scale in petroleum production by alkaline floods

Claim 2

IN A METHOD OF PRODUCING PETROLEUM FROM A PETROLEUMBEARING FORMATION PENETRATED BY A WELL MEANS BY INJECTING A CAUSTIC FLUID INTO SAID FORMATION, THE METHOD OF TREATING SAID FLUID TO PREVENT SCALE DEPOSITION COMPRISING: PROVIDING A FLUID HAVING BICARBONATE IONS WITH SULFUR DIOXSAID PETROLEUM-BEARING FORMATION; TREATING SAID FLUID HAVING BICARBONATE ION CONCENTRATION OF SAID IDE TO REDUCE THE BICARBONATE ION CONCENTRATION OF SAID FLUID; ADDING A CAUSTIC TO SAID TREATED FLUID TO FORM SAID CAUSTIC FLUID; INJECTING SAID CAUSTIC FLUID VIA SAID WELL MEANS INTO SAID INFORMATION; AND PRODUCING SAID PETROLEUM VIA SAID WELL MEANS FROM SAID FORMATION.

Claim 3

In the method of claim 1, the method of treating said fluid having bicarbonate ions, comprising the further steps of: passing a sulfur dioxide gas through a contactor vessel; passing said fluid having bicarbonate ions through said contactor vessel in counterflow with said sulfur dioxide gas to reduce the bicarbonate ion concentration of said fluid by substituting sulfate ions for said bicarbonate ions; and discharging said fluid of reduced bicarbonate ion concentration from said contactor vessel.

Claim 4

The method of claim 2 wherein said sulfur dioxide gas is a flue gas containing sulfur oxides.

Claim 5

The method of claim 2 wherein said fluid having bicarbonate ions is a produced alkaline water that is recovered from an earth forMation.

Claim 6

The method of claim 4 wherein said caustic is added to said treated fluid in an amount sufficient to provide a pH value of said caustic fluid of at least about 11.5.

Claim 9

The method of claim 6 further comprising adding said caustic to at least another portion of said water of reduced bicarbonate ion concentration and mixing said at least another portion with said hot fluid to form said hot caustic fluid.

Claim 10

In a method of producing petroleum from a formation containing petroleum and alkaline water having bicarbonate ions, said formation being penetrated by an injection well and a production well, the steps comprising: a. generating a flue gas having sulfur oxides by firing a flue gas generator with a sulfur-containing fuel; b. producing said alkaline water having bicarbonate ions via said production well from said formation; c. clarifying at least a portion of said produced alkaline water containing bicarbonate ions; c. passing said clarified alkaline water containing bicarbonate ions through a contactor vessel; e. passing said flue gas containing sulfur oxides through said contactor vessel in counterflow with said clarified alkaline water containing bicarbonate ions to reduce the bicarbonate ion concentration of said water; f. discharing said flue gas from said contactor vessel; g. discharging said water of reduced bicarbonate ion concentration from said contactor vessel; h. adding a caustic to said water of reduced bicarbonate ion concentration to form a caustic water; i. injecting said caustic water via said injection well into said formation containing petroleum and alkaline water having bicarbonate ions; and j. producing petroleum and alkaline water having bicarbonate ions via said production well from said formation.

Claim 11

In a method of producing petroleum from a formation containing petroleum and alkaline water having bicarbonate ions, said formation being penetrated by an injection well and a production well, the steps comprising: a. generating a flue gas having sulfur oxides by firing a flue gas generator with a sulfur-containing fuel; b. producing said alkaline water having bicarbonate ions via said production well from said formation; c. clarifying at least a portion of said produced alkaline water containing bicarbonate ions; c. passing said clarified alkaline water containing bicarbonate ions through a contactor vessel; e. passing said flue gas containing sulfur oxides through said contactor vessel in counterflow with said clarified alkaline water containing bicarbonate ions to reduce the bicarbonate ion concentration of said water; f. discharing said flue gas from said contactor vessel; g. discharging said water of reduced bicarbonate ion concentration from said contactor vessel; h. adding a caustic to said water of reduced bicarbonate ion concentration to form a caustic water; i. injecting said caustic water via said injection well into said formation containing petroleum and alkaline water having bicarbonate ions; and j. producing petroleum and alkaline water having bicarbonate ions via said production well from said formation.

Claim 12

The method of claim 8 wherein said flue gas generator is a hot fluid generator that is fired with a sulfur-containing fuel to generate a hot fluid and wherein said caustic is added to said hot fluid to form a hot caustic fluid.