Produced Water Management Strategy and Water Injection Best Practices: Design, Performance, and Monitoring

Abstract

Summary Key factors in framing a produced water management (PWM) strategy include a company's internal and external environments, technology, and business drivers. Emerging trends for establishing an environment-friendly PWM position comprise adoption of these policies:Move toward zero emissions.No discharge to surface or seas.Waste-to-value conversion.Incremental and progressive separation.Proactive efforts to influence partners, regulators, and environmental laws. This paper covers technical approaches for addressing the production, separation, and disposal/injection segments of water injection and reservoir waterflooding procedures and the basis for selecting strategy components and PWM actions. Best practices result both from comprehensive assessments of current PWM tools and from the insights obtained from a decade-long joint industry project (JIP) on produced water re-injection (PWRI). PWRI for waterflooding or disposal is an important strategy for deriving value from waste while preserving environmental integrity during exploration and production (E&P) operations. Advances in best practices and lessons learned for injector design, operation, monitoring, assessment, and intervention provide the basis for cost minimization and green operations. Facility and subsurface engineering are linked through PWM quality targets, pumping needs, injector completions, and facility constraints. Field cases and data mining results (Abou-Sayed et al.2005) show the variation in injector responses and underline the key elements contributing to performance. Field evidence indicates that injectivities suffer in matrix injection schemes despite the injection of clean water. Alternatively, injectivity maintenance using untreated produced water is feasible. The majority of injectors fracture during injection, thereby impacting facilities' statement of requirement (SOR), injector completion, sweep, and vertical conformance. This paper assesses fracture propagation during seawater and produced water injection and its impact on injector performance. Models depicting plugging of formations and fractures, vertical water partitioning, and well testing are discussed. Best practices are highlighted and the impacts on injection strategy outlined. Several field cases, as well as water injection design and analysis tools for quantifying the impact on flood and well performance, are presented. Introduction PWRI technology application for oilfield management has been steadily increasing over the last decade in various parts of the world (Sirilumpen and Meyer 2002; Van den Hoek et al.2002; Furtado et al. 2005; Hjelmas et al. 1996). Successful injection operations have been reported by operators in the North Slope of Alaska, the west coast of Africa, and the North Sea. PWRI offers the dual benefit of disposal of oil-filled waste water and solids in an environmentally safe way and enhanced hydrocarbon recovery by improving reservoir fluid sweep and pressure maintenance. The successful application of this technology in the oil field does not depend only on the disposal of solids/contaminants, but also on the maintenance of injectivity for effective sweep and injection conformance for improved recovery. This paper discusses the physical phenomena, namely matrix and fractured injection, involved in PWRI and the associated issues with regard to injectivity and facility requirements. A fracture plugging and propagation model is presented to explain the cyclic injection pressure behavior observed in some injectors. Thermal fracturing can allow fracture containment and reduce injection system requirements. Field cases clearly showing the effect of injection water temperature on fracture pressure and injectivity are discussed. The knowledge gained from the JIP is used to establish guidelines and best practices for implementing a PWM strategy.

Water Quality and Well Injectivity: Do Residual Oil-in-Water Emulsions Matter?

“…Because of the large and increasing stream of oilfi eld-produced waters and the tightening of environmental regulations, water handling is becoming a major issue for the oil industry. PWRI for oil-production support through pressure maintenance and enhanced-oil-recovery (EOR) methods is among the best options to convert waste to value and becomes increasingly the main destination of oilfi eld-produced waters Souza et al 2005;Abou-Sayed et al 2007). …”

“…Matrix injection results in a continuous well-injectivity decline even in soft formations (Detienne et al 2005;Abou-Sayed et al 2007). Actually, recent field evidence indicates that most water-injection wells are likely to be fractured (Abou-Sayed et al 2005;Abou-Sayed et al 2007; Van den Hoek et al 2008) and that regular well acidizing is required to maintain injectivity even with clean water (Van den Hoek et al 2008). Thus, injectivity in hard formations is increasingly viewed as being dictated by a dynamic coupling between fracture growth and plugging (Detienne et al 2005).…”

“…Thus, while fracture injection offers good injectivity, the associated risks could make it impossible to operate in some reservoirs . A discussion of these issues can be found in Abou-Sayed et al (2007).…”

Produced water re-injection in a non-fresh water aquifer with geochemical reaction, hydrodynamic molecular dispersion and adsorption kinetics controlling: model development and numerical simulation

“…Precious studies show that formation damage and injectivity decline are two major drawbacks associated with PWRI performance in hydrocarbon aquifer. Some past and recent studies were focused on understanding formation damage mechanisms (Salehi and Settari 2008;Prasad et al 1999;Davidson 1979;Marchesin et al 2011;Abou-Sayed et al 2005;Zhang et al 1993;Todd 1979;Ochi et al 2007;Nabzar et al 1997;De Zwart 2007;Faruk 2010;Lawal et al 2011;Lawal and Vesovic 2010;Wang and Le 2008;Li et al 2012).…”

Mathematical Modelling of Non-Uniform External Cake Profile in Long Injection Wells

“…Drastic decline of well injectivity is a widespread phenomenon which has been widely reported for fresh and hot water storage in aquifers, for industrial waste disposal, during well drilling and completion, for seawater and produced-water injection into oilfields and geothermal reservoirs (Schechter, 1992;Khilar and Fogler, 1998;Cheng et al, 2000Cheng et al, , 2004Abou-Sayed et al, 2007;Civan, 2011;Rosenbrand et al, 2014). The phenomenon is explained by deep-bed filtration of solid and liquid particles associated with the injected fluids, causing permeability decline (Oliveira et al, 2014;Kalantariasl et al, 2014bKalantariasl et al, , 2015b.…”