Summary Recent studies highlight the significant role of drilling fluid elasticity in particle suspension and hole cleaning during drilling operations. Traditional methods to quantify fluid elasticity require the use of advanced rheometers, which are not suitable for field applications. The main objectives of this study were to investigate the factors influencing drilling fluid viscoelasticity in the field and develop generalized models for determining the viscoelasticity of a drilling fluid using standard field testing equipment. Ninety-three fluid formulations used in this study included field samples of oil-based drilling fluids as well as laboratory samples of water-based, invert emulsion and other oil-based fluids. Basic rheological characterizations of these fluids were done by using a funnel viscometer and a rotational viscometer. Elastic properties of the drilling fluids (quantified in terms of the energy required to cause an irreversible deformation in the fluid’s structure) were obtained from oscillatory tests conducted by using a research-grade rheometer with double gap concentric cylinder geometry. Using an empirical approach, two noniterative models for quantifying drilling fluid elasticity were developed (one for unweighted and the other for weighted drilling fluids) by correlating test results from a funnel viscometer and a rotational viscometer to energy required to cause an irreversible deformation of the fluid’s elastic structure. The generalized models for the unweighted and weighted viscoelastic drilling fluids were able to predict the elasticity of drilling fluids with a mean absolute error of 4.67 and 5.28%, respectively. In addition, the models offer practical versatility by requiring only standard drilling fluid testing equipment to predict viscoelasticity. Experimental results showed that nonaqueous fluid viscoelasticity is inversely proportional to the oil-water ratio (OWR), and the presence of clay greatly debilitates the elasticity of the drilling fluids while enhancing their viscosity. In this paper, we present models for estimating unweighted and weighted drilling fluid elasticity using standard drilling fluid field testing equipment. Furthermore, we proposed a prudent approach for quantifying the viscoelastic property of a drilling fluid by measuring the amount of energy required to irreversibly deform a unit volume of viscoelastic fluid. The new models, combined with the recommended use of the energy dissipation (ED) concept, provide practical tools that can be used for developing optimum drilling fluid formulations and hydraulic programs for effective hole cleaning operations, improved equivalent circulating density (ECD) management, and mitigating barite sag problems.

The ubiquity of complicated and extended-reach horizontal wellbores with tighter windows has spurred the copious use of the rotary steerable system (RSS) in drilling operations. This magnetic-powered RSS technology, initially designed for the offshore drilling market, has proven to be an effective solution to the increasingly complex challenges in the land-based market. Although durable, as with other mechanical devices, equipment failure and malfunction may occur during drilling operations. The impairments of these expensive high-end systems while drilling often lead to costly trips and NPTs, which can be avoided with regular maintenance practices. Apart from these regular maintenance practices, it is also paramount to devise proactive techniques while drilling that will enhance the life cycle of these systems and prevent rampant and uneconomical trips. This paper presents a proven methodology that was used to eliminate the rampant RSS tool failures encountered on multiple rigs in Southern Alberta, Canada. While RSS tool failures have traditionally been attributed to the barite and mud system, scientific root cause analysis showed that ferromagnetic iron metal generated from different sources while drilling induced these failures. Ferromagnetic Iron has the potential to cause interference with downhole magnetic tools, causing them to fail and have solids entrapped in them. An ingenious operational procedure was devised and implemented using strategically generated magnetic fields in the mud circulation system at different locations. These magnetic fields strip the mud system of ferromagnetic materials to prevent damage to RSS tools. This procedure was also backed up with a novel testing technique that identifies and quantifies the presence of ferromagnetic materials in the mud system, which can be tracked on the daily drilling report or posted on a digital database. The test results help engineers detect the buildup of ferromagnetic iron in the mud system (indicating the strength of the magnetic fields) and the appropriate mitigation strategy to employ, which may include strengthening the magnetic fields and using centrifuges depending on the scenario. This successful approach eliminated RSS tool failures on multiple rigs and reduced Tool-Failure NPTs drastically by over 47% on average. This paper breaks down, showcases, and elucidates a practical engineering solution to a prevalent drilling problem, with easy-to-follow steps that can be replicated by mud engineers and technicians anywhere in the world.

In order to improve the global sustainability benchmarks of the drilling industry, there is a need to adopt more eco-friendly practices that will diminish the adverse environmental impact of drilling operations. Responsible energy development should prioritize environmental protection and sustainable practices, including the drilling fluid system selection. An efficient environmental approach involves the recycling of produced water as a drilling fluid to combat its detrimental disposal requirements as well as reducing the usage of freshwater and potentially carcinogenic oil-based mud in drilling operations. While field data have shown that recycled production water can have superior performance and lower costs, the widespread utilization of produced water has experienced slow adoption due to its unique set of challenges. These challenges include variability in ionic composition, increased corrosion, and scaling potential, along with health and safety considerations, which reduce its overall desirability. These factors are further compounded by a general lack of technical knowledge around water chemistry dynamics, treatment, and system management. There is a need for a "playbook" that demystifies the technical complexities of produced water, thereby bridging a crucial gap in the drilling fluids literature and accelerating the adoption of this lower environmental footprint fluid. This paper presents a comprehensive overview and pragmatic insight into the usage of produced water for drilling operations from real-life case studies in Western Canada. This paper is designed as an aid to understand the associated screening, testing, treatment, and practical pitfalls of using production water as a drilling fluid, which is illustrated with real-life data. The aim is to encourage and accelerate the adoption of production water as a sustainable source of superior drilling fluid systems by more operators and drilling fluid service providers. Consequently, improving the environmental sustainability of the drilling industry.

Recent studies highlight the significant role of drilling fluid elasticity in particle suspension and hole cleaning during drilling operations. Traditional methods to quantify fluid elasticity require the use of advanced rheometers not suitable for field application. The main objectives of the study were to develop a generalized model for determining viscoelasticity of a drilling fluid using standard field-testing equipment, investigate the factors influencing drilling fluid viscoelasticity in the field, and provide an understanding of the viscoelasticity concept. Over 80 fluid formulations used in this study included field samples of oil-based drilling fluids as well as laboratory samples formulated with bentonite and other polymers such as partially-hydrolyzed polyacrylamide, synthesized xanthan gum, and polyacrylic acid. Detailed rheological characterizations of these fluids used a funnel viscometer and a rotational viscometer. Elastic properties of the drilling fluids (quantified in terms of the energy required to cause an irreversible deformation in the fluid's structure) were obtained from oscillatory tests conducted using a cone-and-plate type rheometer. Using an empirical approach, a non-iterative model for quantifying elasticity correlated test results from a funnel viscometer and a rotational viscometer. The generalized model was able to predict the elasticity of drilling fluids with a mean absolute error of 5.75%. In addition, the model offers practical versatility by requiring only standard drilling fluid testing equipment to predict viscoelasticity. Experimental results showed that non-aqueous fluid (NAF) viscoelasticity is inversely proportional to the oil-water ratio and the presence of clay greatly debilitates the elasticity of the samples while enhancing their viscosity. The work efforts present a model for estimating drilling fluid elasticity using standard drilling fluid field-testing equipment. Furthermore, a revised approach helps to describe the viscoelastic property of a fluid that involves quantifying the amount of energy required to irreversibly deform a unit volume of viscoelastic fluid. The methodology, combined with the explanation of the viscoelasticity concept, provides a practical tool for optimizing drilling operations based on the viscoelasticity of drilling fluids.