NOVEL VISCOUS FLUIDS SYSTEMS FROM PRODUCED AND FLOW BACK WATERS
In certain instances high levels of boron is present in produced or flowback water after it has been treated. The boron or borates tend to cause the guar to cross-link and become viscous too early which may cause undue wear or other problems with the surface equipment. It has been found that in the presence of low pH the viscosifier typically does not cross-link in the presence of a borate allowing the finished water to be used to hydrate the fluid. The fluid including the now hydrated linear gel is then subject to a chelating process so that the boron may be sequestered. Once the originally present borate is sequestered a slowly soluble borate is added to cause the linear gel to cross-link at the desired point in time.
1 . A well treatment material method comprising:
lowering a pH of a finished water,
hydrating a viscosifier with the finished water,
chelating a boron present in the finished water and the viscosifier,
raising a pH of the finished water and the viscosifier, and
adding a slowly soluble borate to the finished water and the viscosifier.
2 . The method of claim 1 wherein, the step of lowering the pH consists of lowering the pH to below 7.
3 . The method of claim 1 wherein, the step of lowering the pH consists of lowering the pH to between 6 and 6.5.
4 . The method of claim 1 wherein, the step of raising the pH consists of raising the pH to above 7.
5 . The method of claim 1 wherein, the step of raising the pH consists of raising the pH to between 9.5 and 12.
6 . The method of claim 1 wherein, the step of raising the pH consists of raising the pH to between 10 and 11.
7 . The method of claim 1 wherein, the slowly soluble borate is ulexite.
8 . The method of claim 1 wherein, a fast crosslinker is added with the slowly soluble borate.
9 . The method of claim 8 wherein, a fast crosslinker is a borax solution.
10 . The method of claim 8 wherein, a fast crosslinker is potassium borate.