New Water-Based Mud Balances High-Performance Drilling and Environmental Compliance

Abstract

Summary A new water-based mud system was successfully introduced as a high-performance, environmentally compliant alternative to oil and synthetic emulsion-based muds (OBM/SBM). Historically, emulsion muds have been the systems of choice when drilling challenging onshore, continental shelf, and deepwater wells to minimize risk, maximize drilling performance, and reduce costs. However, environmental constraints, a high frequency of lost circulation, and the high unit cost of emulsion systems sometimes negate the benefits of their use. Conventional water-based muds (WBM) offer the benefits of environmental compliance, attractive logistics, and a relatively low unit cost but consistently fail to approach the drilling performance of OBM and SBM. The new high-performance, water-based mud (HPWBM) is designed to close the significant drilling performance gap between conventional WBM and emulsion-based mud systems. The system has undergone extensive field testing on very challenging onshore, deepwater, and continental shelf wells that would otherwise have been drilled with oil or synthetic-based muds. This paper provides a detailed, technical overview of the new system, discusses its inherent environmental advantages, and presents case histories comparing performance to offset wells drilled with emulsion and conventional WBM systems. Introduction The industry is increasingly drilling more technically challenging and difficult wells. Exploration and development operations have expanded globally as the economics of exploring and producing for oil and gas have improved with advancements in drilling technology. Advanced drilling operations such as deep shelf, extended reach, horizontal, and deepwater are technically challenging, inherently risky, and expensive. OBM and SBM have many inherent advantages over water-based drilling fluids, including temperature stability, tolerance to contamination, and corrosion protection. However, the fluid attributes of concern in this discussion are those most directly related to drilling performance and environmental issues. With consideration to reducing drilling problems such as torque and drag, stuck pipe, low rates-of-penetration, and wellbore stability, these wells are generally drilled with emulsion-based muds. Environmental legislation governing drilling waste is continually restricting the discharge limits of spent muds and drilled cuttings. Operators are challenged with achieving a balance between minimizing the potential environmental impact of the drilling fluid against drilling objectives. The inherent advantages provided by emulsion muds are increasingly being offset by environmental compliance restrictions.

A review on borehole instability in active shale formations: Interactions, mechanisms and inhibitors

“…Oil Based Muds (OBMs) were the first option recommended as a 'certain' solution to avoid borehole instability caused by shales. Their applications provided outstanding clay inhibition, lubricity, temperature stability, tolerance to contamination, and corrosion protection (Dye et al, 2006). However, the environmental concerns and regulations on OBMs have resulted in their limited applications.…”

Drilling Fluid: State of The Art and Future Trend

“…The water based drilling fluids, which simulate the performance of the oil-based drilling fluid are commonly referred to as high performance water based fluids (HPWBF) (Morton, 2005;West and Morales, 2006;Dye, 2006;Patel, 2007;Marin et al, 2009). The main benefits of HPWBF include the reduction of environmental impacts, and lower down costs associated with cuttings and fluids disposal.…”

“…According to Dye et al, (2006), unlike WBDFs, OBDFs do not dissolve salts because they are non polar. They do not interfere with the contents of the reservoir and the porous media because the base oil (no.2 diesel) is native to the reservoir.…”

Research on the Preparation and Mechanism of the Organic Montmorillonite and Its Application in Drilling Fluid

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“…In oil-well drilling, bentonite is added in drilling fluids for viscosity control, to aid the transfer of cuttings from the bottom of the well to the surface, and for filtration control to prevent filtration of drilling fluids into the pores of productive for mations [9]. Compared to water-based drilling fluid, oil-based drilling fluid has many inherent advantages, including excellent clay inhibition, wellbore stability, lubricity, antiaccretion property, temperature stability, tolerance to contamination, and corrosion protection [6]. The high clay 2 Journal of Nanomaterials solids content in drilling fluid has several adverse effects: (1) greatly reduces the rate of penetration [7]; (2) increased chances of differential sticking; and (3) is the major cause of excessive torque and drag [10].…”