Innovative Chemistry for Drilling Fluid Additives

Abstract

The enhanced performance of drilling fluids, especially High-Temperature, High-Pressure (HTHP) compatibility, will allow faster and safer drilling in challenging environments. This paper presents a novel class of synthetic polymers that were developed as high performance rheology modifiers (viscosifiers). The leading polymer candidate was shown to be an effective thickener, with excellent salt-tolerance and thermal stability compared to conventional viscosifiers used in water-based drilling fluids.This new class of synthetic polymers was suitable for demanding drilling conditions where conventional viscosifiers cannot perform satisfactorily. For example, xanthan gum is known to start losing rheological properties above 250-300 o F so it is not always suitable for HTHP drilling operations. A desired rheology modifier should possess similar rheological properties to xanthan gum (e.g. highly shear thinning) with enhanced salt tolerance and thermal stability. These enhanced properties will allow drilling fluids to maintain critical functions under harsher field conditions. This paper presents the basic characteristics of the newly developed polymeric rheology modifier as well as its rheological and thermal stability properties. The rheological properties of the polymers were studied in fresh water, in brines and in formulated drilling fluids. Thermal stability studies were conducted using stainless steel pressure aging cells, a roller oven, and a conventional oven. The novel polymer developed was shown to exhibit a similar thickening efficiency and rheological profile (i.e. shear thinning) to xanthan gum. After thermal aging up to 350-375 o F (177-190°C) for 16 hours, drilling fluids based on this polymer were shown to maintain excellent rheology and suspension power. The new synthetic rheology modifier also demonstrated synergistic effects with other ingredients commonly used in water-based drilling fluids, further enhancing thermal stability.Development of these high-performance drilling fluid additives is critically important to the drilling industry. HTHP compatible drilling fluids may allow more environmentally-friendly drilling operations to be undertaken in a safe and efficient manner.

Nanomaterial-Based Drilling Fluids for Exploitation of Unconventional Reservoirs: A Review

“…Wang et al [122] have suggested that an ideal viscosifier used for HPHT WBDF should possess similar rheological properties to xanthan gum, exhibiting high shear thinning properties with enhanced salt tolerance and thermal stability. For WBDF, a synthetic polymeric viscosifier has been developed which exhibits exceptional thickening efficiency, salt tolerance, and thermal stability at temperature ranges of 450-464 K in the presence of monovalent halide brines [123]. Further development of this synthetic polymeric viscosifier increased thermal stability in the range of 450-478 K. Tehrani et al [107] have argued that a different approach is needed to generate viscosity by utilizing medium-molecular-weight polymers which adsorb over dispersed solids and contact with dissolve polymers to yield highly shear-thinning rheology.…”

Drilling fluid loss control via implementing the FMI and DSI logs to protect environment

“…A number of studies have been carried out to minimize the damage resulting from drilling fluids where most of them have focused on variation of additives to drilling fluids or use of synthesized drilling muds to minimize the environmental damage; nevertheless, none of these methods have become practically implemented in the industry (Amanullah and Yu 2005;Moslemizadeh et al 2015;Tehrani et al 2009;Zheng et al 2011). Drilling fluid loss occurs mainly through fractures into the formation and these problems are more pronounced in offshore fields as compared to land (Aston et al 2004;Labenski et al 2003).…”