Operators in unconventional regions manifest corrosion and wear on their drilling equipment differently. A drilling fluid maintains contact with the drill string and its components, making it a key factor when considering the causes of corrosion and wear, fluid design that minimizes wear is paramount. The effects of abrasive formations on the drillstring, controlling oxidation, and minimizing wear are of primary concern.
The fluids tested with different methodologies in the laboratory to best represent the field. Along with more well-known testing, a new means of testing tool wear and its implication to drill string and hard-banding technology was introduced. Each area-of-concern may be addressed with particular additives to the drilling fluid. Three different types of drilling fluid was tested and compared. When comparing lubricity coefficients, a high performing water-based fluid (HPWBF) and an oil-based fluid (OBM) outperformed a brine water based fluid by 60.5﹪ & 55.1﹪, respectively. Wear data was also assessed to reveal a similar trend.
With knowledge of the different environments and products, a drilling fluid formulated with a high performing drilling enhancer (HPDE) and corrosion inhibitors so that oxidation was controlled. Using the additives, the operator ended up having to replace less of the drill-string when in comparison to other wells. In West Texas, proper viscosifying agents to suspend the solids along with mechanical solids control equipment needed to address recycling the drilling fluid, which was expected to build up abrasive solids. The HPDE would be added to reduce the coefficient of friction (CoF) of the fluid and minimize wear caused by interaction of the drillstring and abrasive formation. Experiences from a laboratory correlating the coefficient of friction to the wear rate have proved fruitful for field applications. The operator will have the option to use a more cost-effective environmentally friendly HPWBF.
Using this information, the well planning allows for application and or dosing preventing drilling string/hard-band wear. By controlling the abrasivity of the environment, chemical additions to the drilling fluid can aid in improving the wear-rates on a known material.
