High temperature high salt low end rheology modifiers
AssigneesCNPC USA Corporation, Beijing Huamei, Inc., China National Petroleum Corporation
InventorsJANINE SHIPMAN, MENG LU, WEIBIN ZHA
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Abstract
A low-end rheology modifier for adjusting rheological characteristics of water-based drilling fluid systems, particularly for high salt, high density drilling fluids in high temperature and high-pressure applications. The low end rheology modifier comprises a copolymer and laponite clay, the copolymer comprising tert-Butylacrylamidosulfonic acid (TBAS) and n-vinylpyrrolidone (NVP) crosslinked with N,N′-Methylenebis(acrylamide).
Claims8
A method for improving or modifying theological properties of a water- based drilling fluid during geothermal drilling operations, the method comprising:
- drilling a downhole well, and
- pumping a water-based drilling fluid into the well while drilling, the water-based drilling fluid comprising a low-end rheology modifier;
- wherein the low-end rheology modifier comprises laponite clay and a copolymer and wherein the presence of the low-end rheology modifier improves or modifies the theological properties of the water-based drilling fluid in the well.
Dependencies are inferred from the claim text.