Chrome free water-based wellbore fluid

Abstract

Methods for maintaining the rheology and reducing the fluid loss of chrome-free, aqueous-based wellbore fluids under high temperature-high pressure conditions are disclosed. The method may comprise formulating the chrome-free, aqueous wellbore fluid with an aqueous base fluid, at least one chrome-free viscosifier, at least one chrome-free fluid loss control additive, at least one chrome-free dispersant; and circulating the chrome-free aqueous-based wellbore fluid in a wellbore at temperatures exceeding 300° F.

Description

BACKGROUND OF INVENTION[0001]1. Field of the Invention[0002]Embodiments disclosed herein relate generally to water-based wellbore fluids and methods of using such fluids. In particular, embodiments disclosed herein relate generally to water-based fluids being chrome-free.[0003]2. Background Art[0004]During the drilling of a wellbore, various fluids are typically used in the well for a variety of functions. The fluids may be circulated through a drill pipe and drill bit into the wellbore, and then may subsequently flow upward through wellbore to the surface. During this circulation, the drilling fluid may act to remove drill cuttings from the bottom of the hole to the surface, to suspend cuttings and weighting material when circulation is interrupted, to control subsurface pressures, to maintain the integrity of the wellbore until the well section is cased and cemented, to isolate the fluids from the formation by providing sufficient hydrostatic pressure to prevent the ingress of for...

AI Technical Summary

Benefits of technology

The patent text describes a method for maintaining the rheology and reducing the fluid loss of a chrome-free, aqueous-based wellbore fluid in high-temperature conditions. The method involves formulating the fluid with an aqueous base fluid, a chrome-free viscosifier, a chrome-free fluid loss control additive, and a chrome-free dispersant. The fluid should have a thermal plastic viscosity of less than 70 cP and a fluid loss of less than 20 mL. The method also involves circulating the fluid in a wellbore at a temperature of at least 300° F. The patent also describes the use of specific additives, such as polyacrylamide, polyacrylate, and vinyl-based copolymers, to improve the performance of the fluid. Overall, the method helps to maintain the viscosity and prevent fluid loss of the fluid in high-temperature environments.

Problems solved by technology

Under high temperature / high pressure (HTHP) drilling conditions, control of fluid properties becomes a major challenge.

Fluid loss control is an issue in high temperature environments due to degradation of many polymers at high temperatures and high pressures.

However, the presence of chrome in a fluid increases the potential for gel formation, which can create significant issues in HTHP applications.

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