Method and composition for controlling fluid loss in high permeability hydrocarbon bearing formations
US5981447A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 28, 1997 |
| Grant date | Nov 9, 1999 |
| Priority date | — |
| Expiry date | May 28, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S507/925
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
A chemical system and method to stop or minimize fluid loss during completion of wells penetrating hydrocarbon formations are provided. The inventions relates to formulating a highly stable crosslinked hydroxyethyl cellulose (HEC), control released viscosity reduction additives, and user friendly packaging. The chemical system contains a linear HEC polymer solution, a low solubility compound which slowly raises the fluid pH, a chelating agent which further increases the pH level beyond the equilibrium achievable by the low solubility compound, a metal crosslinker which crosslinks HEC at elevated pH, a crosslink delaying agent which allows fluid viscosity to remain low until the fluid reaches the subterranean formation, and optionally an internal breaker. The chemical additives are packaged as an integrated pallet and transported to a field location which allows operators to conveniently mix them before pumping. There is also provided a dry granulated crosslinked polysaccharide for use as a fluid loss control agent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.