OIL RECOVERY PROCESS INCLUDING ENHANCED SOFTENING OF PRODUCED WATER

摘要

A process is provided for treating produced water resulting from an oil recovery operation. Produced water is subjected to a softening process wherein a caustic or other softening reagent is added to the produced water to increase the pH of the produced water. Downstream of softening, there is provided an evaporator for evaporating at least a portion of the produced water and producing steam and a concentrated brine. At least a portion of the concentrated brine is recycled upstream of the evaporator and mixed with the produced water and the softening reagent to enhance the softening process.

主权项

1. A method of recovering oil from an oil-bearing formation, comprising:
a. recovering an oil-water mixture from the oil-bearing formation; b. separating oil from the oil-water mixture to produce oil and produced water having hardness therein; c. directing the produced water to an evaporator and evaporating at least a portion of the produced water to produce a concentrated brine and steam; d. condensing the steam to form a distillate; e. directing the distillate to a steam generator and heating the distillate in the steam generator to produce steam; f. injecting the steam produced by the steam generator into an injection well; g. softening the produced water upstream of the evaporator by raising the pH of the produced water by:
i. mixing a caustic with the produced water;ii. directing at least a portion of the concentrated brine from the evaporator and mixing the concentrated brine with the produced water to enhance softening; andiii. wherein the caustic and concentrated brine combine to raise the pH of the produced water and soften the produced water.