Clay-Free High Performance Water-Based Drilling Fluid for Extreme High Temperature Wells

Abstract

Growing demands to operate in harsh high temperature environments require robust drilling fluid performance to drill in such conditions. Water-based drilling fluids offer significant environmental advantages compared to invert-emulsion fluids (IEFs). High performance (HP) water-based drilling fluids are particularly advantageous compared to conventional water-based systems because they offer faster rates of penetration (ROPs), enhanced hole cleaning and shale inhibition, and improved wellbore stability. Most HP water-based drilling fluids can only tolerate operating temperatures up to 300°F attributed to a strong dependence on biopolymer-based viscosifiers. Thus, deeper exploration in extreme high temperature reservoirs (Ͼ300°F) requires new drilling fluid technologies. A new high performance, high temperature water-based drilling fluid that is thermally stable at 400°F has been developed to meet these demands.The new fluid system was fully formulated using a multimixer, and the resulting fluids were hot rolled at 150°F for 16 hours to condition the fluid before testing. The conditioned fluids were then further subjected to dynamic or static aging conditions with temperatures ranging from 300 to 400°F. The aged fluid viscosity was examined using a direct-indicating viscometer, and the pH was determined with a pH meter. The fluid loss properties of the fluids were determined by both API filtration and high-pressure/ high-temperature (HP/HT) filtration at 350°F in according with the API recommended practice.This paper presents the detailed study of the high performance, high temperature water-based drilling fluid formulated with 10.0-17.0 lbm/gal densities. The fluid exhibits a stable rheological profile. For example, a 14.0 lbm/gal formulation aged at 150°F for 16 hours yielded a plastic viscosity of 29 cp and a yield point of 22 lbm/100 ft 2 . After static aging for 48 hours at 400°F, the fluid gave a plastic viscosity of 27 cp and yield point of 24 lbm/100 ft 2 . The new fluid maintains stable viscosity, adequate suspension, low shear strength, shale stability, and filtration control up to 400°F.This thermally stable, clay-free system exhibits good shale inhibition and is environmentally acceptable for both land and offshore drilling. This HP water-based drilling fluid is formulated with a novel synthetic polymer viscosifier and filtration control agent, allowing removal of thermally labile biopolymers without the addition of clay-based viscosifiers. The new formulation provides reliable thermal stability that can readily function in extreme high temperature wells, while preserving the benefits of HP water-based drilling fluids.

Application of Psyllium Husk as a Friendly Filtrate Reducer for High-Temperature Water-Based Drilling Fluids

“…When the hot rolling temperature is greater than 140 °C, it is susceptible to oxidative decomposition or thermal degradation at high temperature, leading to breakage of the molecular chain and losing the control effect on the performance of the drilling fluid. 9 − 11 , 21…”

“…At the same time, the solid phase will form a thinner mud cake in the formation. − Multiple research studies have demonstrated that when the fluid loss of the drilling fluid occurs, it will cause the shale formation to hydrate and swell, which will induce the instability of the borehole wall. When the fluid loss is large, a thicker mud cake will be produced, which is prone to drilling accidents such as wear of drilling tools and stuck drills. − When drilling into deep formations, the components of the drilling fluid are prone to high-temperature degradation and failure, thus deteriorating the performance of the drilling fluid , and triggering a series of downhole complex accidents . Therefore, the development of high-temperature-resistant drilling fluid treatment agents, effective control of the high-temperature filtration, and wall-building performance of the drilling fluid has always been the research focus of deep well and ultradeep well drilling engineering.…”

Comparison between the Effect of Local Katira Gum and Xanthan Gum on the Rheological Properties of Water-based Drilling Fluids

“…For this purpose, many chemical additives are used including clays, solvents, and polymers. Polymers in different types are widely used with the water-based muds to improve the rheological properties of the mud, and the mud is sometime called polymer mud [5]- [7]. At present, researchers and companies are more focusing on the application of biopolymers which are definitely not poisonous and cheaper while having significantly less influence on formation damage [8], [9].…”

Inhibiting shale hydration and dispersion with amine-terminated polyamidoamine dendrimers

“…Oil-based drilling fluids are the first choice for most shale formations because of the outstanding shale stability, however, the drawback of high cost and stringent environmental legislation make them a much less attractive alternative than before (He et al, 2014;Stamatakis et al, 1995;Suter et al, 2011). Consequently, much research has been transferred to improve the inhibitive properties of water-based drilling fluids with the eventual goal of replacing oil-based drilling fluids, which is also a hallmark of high performance water-based drilling fluid (Galindo et al, 2015).…”

“…Based on the understandings of shale hydration mechanisms and the physical-chemical interactions between shale and drilling fluid, lots of work has been carried out to evaluate and seek solutions to mitigate and control the reactive shale formations during the past decades (Van Oort et al, 1994;Van Oort, 1997). Numerous chemicals including inorganic salts, formates, organic amine compounds, polymers, silicates and polyglycerols have been used with different mechanisms such as hydration inhibition, reduction of pore pressure transmission, or cuttings encapsulation (Galindo et al, 2015;Patel et al, 2007;Reid et al, 1995;Van Oort, 2003;Xuan et al, 2013;Zhang et al, 2001). Based on these chemical inhibitors, several inhibitive water-based drilling fluids have been established and utilized in the field (Donham and Young, 2009;Patel and Gomez, 2013;Stamatakis et al, 1995;Young and Ramses, 2006).…”