×

Use of multiple treatment agents to reduce hardness of an oilfield produced water

  • US 5,879,563 A
  • Filed: 05/30/1997
  • Issued: 03/09/1999
  • Est. Priority Date: 04/15/1997
  • Status: Expired due to Fees
First Claim
Patent Images

1. A process for reducing the hardness of an oilfield produced water comprising:

  • a primary chemical reaction stage, including adding lime to an initial oilfield produced water containing an initial concentration of scale-forming ions that provide said initial oilfield produced water with an initial hardness, and reacting said lime to form a first portion of a scale and an intermediate water containing an intermediate concentration of said scale-forming ions that provide said intermediate water with an intermediate hardness, said intermediate hardness being substantially less than said initial hardness;

    a secondary chemical reaction stage, including adding caustic to said intermediate water and reacting said caustic to form a second portion of said scale and a product water containing a product concentration of said scale-forming ions that provide said product water with a product hardness, said product hardness being substantially less than said intermediate hardness and the difference between said initial hardness and said product hardness being a total hardness reduction with said primary chemical reaction stage having a primary reduction contribution to said total hardness reduction and said secondary chemical reaction stage having a secondary reduction contribution to said total hardness reduction; and

    removing said first and said second portions of said scale from said product water.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×