Abou sayed

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Abou sayed

  1. 1. Reference Section Produced Water Management Strategy – Saving the Asset from Drowning in Produced Water a report by Dr Ahmed S Abou-Sayed Production optimisation and improving a project’s following declared policies: net present value (NPV) for global hydrocarbon producers need strategies for produced water • a move towards zero emission; management (PWM), in order to eliminate • no discharge to surface or seas; significant economic and environmental barriers. • waste-to-value conversion; PWM issues hamper production by restricting • incremental and progressive separation; and additional development or adding costs (US$0.15 to • pro-activity to influence partners, regulators and US$2.50/barrel of oil (BoO)). Operators raise the environmental laws. Dr Ahmed S Abou-Sayed left BP economic limit for well operability or abandon Exploration in 1999 to establish existing wells, while substantial recoverable reserves PWM strategies must be tooled in a technicalAdvantek International, a consulting firm based in Houston, Texas. He remain in situ. PWM poses the biggest challenge, yet approach to addresses production, separation and holds advanced engineering degrees offers considerable benefits to brownfield operators. disposal/injection operational segments of water and has over 25 years of experience within the petroleum injection and waterflooding. Management must industry covering technology While operators around the globe experience provide the basis for selection of PWM strategy development, management and identical problems, local conditions and components and steer actions to increase revenue technical consultancy. His work has focused within the areas of well requirements dictate that solutions are region- and lower project cost with no harm to the integrity, well stimulation, specific. Regions can vary significantly and environment. Best practices must be based on results production and reservoir boundaries may be set geologically, geographically or of comprehensive assessments of current PWM tools geomechanics and environmental compliance, where he has been politically. An obvious example is PMW in offshore and insights gained from industry projects. extensively involved in produced deepwater conditions in contrast to onshore and/or water management and oil field waste disposal. He holds six the Arctic or other sensitive areas. Produced water re-injection (PWRI) for water-industrial patents and has authored flooding/disposal is an increasingly important strategy and co-authored over 90 technical PWM issues are multi-faceted. In many cases, the toward converting waste to value and preserving the publications. Throughout his career, he has chaired and participated in overall solution may require several separate steps environment’s integrity during exploration and numerous steering and for complete resolution (reduction, chemical production (E&P) operations. Best practices and implementation committees, served on the editorial board of two removal, profile control, separation, treatment, lessons learned for injector design, operation, scientific journals and received disposal and waterflooding use, etc.). Hence, two monitoring, assessment and intervention provide cost several achievement awards. dominating themes emerge from the stakeholders’ minimisations and efficient, green operations. point of view: the need for holistic PWM and the absence of ‘silver bullets’. Facility and subsurface engineering are linked through produced water (PW) quality targets, Operators should follow the UN waste management pumping needs, injector completions and facility priorities/hierarchy framework. Principally, PWM constraints. Field cases and data mining will show must aim to: the wide variation in injector responses and underline the basis for performance. Field • reduce (water shut-off, downhole separation and evidence indicates that injectivities can suffer reinjection, minimise chemicals); significantly in matrix injection schemes despite the • reuse (treat, irrigations and industrial uses); injection of clean water. Alternatively, injectivity • re-form; maintenance, when injecting untreated PW, is • recycle (waterflooding); and feasible and practical. • replace (injection). The majority of injectors appear to be fractured. Key factors in framing PWM strategies include the Fracturing has a major impact on facilities’ company’s internal and external environments (see statement of requirements (SOR), injector Table 1) and its technology and business drivers. completion, sweep and vertical conformance. Emerging trends establish an environmentally- Fracture propagation during seawater and PW2 friendly PWM position which comprises one of the injection impacts injector performance. Models BUSINESS BRIEFING: EXPLORATION & PRODUCTION: THE OIL & GAS REVIEW 2005
  2. 2. Produced Water Management Strategy Table 1 Internally Operating companies have unique characteristics. The business scope, scale, human and intellectual capital can be leveraged by information technology to improve business performance through knowledge management, shared data and an open business model. Externally The environment is framed by service sector ability to deliver new technology and by vendor relationships. Understanding the tension existing between vendor deliveries to operating companies compared with smaller operators (striper wells) is important in setting a strategy for best practices. Implementation of novel technology Implementation of novel technology or process to operate within best practice paradigms is improved through multilateral ventures between vendors and operators (e.g., produced water re-injection (PWRI) joint industry projects (JIP) and downhole oil–water separation (DHOWS) consortia). Both sides (operators and service companies) have maintained competitive advantage through internal development and bilateral ventures with each other. Recent industry consolidation and oil price volatility creates an environment where vendor innovation and risk can be enhanced by proactive multilateral ventures. The vendor relationship This is that of a service provider. The core skill of any operating company is operatorship. This may appear an outdated concept, but is valid as long as the operator assumes the financial, technical and contractual risk. Effective relationships to guide, provide feedback and directly assist vendors to integrate best practices can improve service delivery.depicting formation and fracture plugging, vertical for oil producers. When it becomes economicallywater partitioning and well testing exist. Best unfeasible to treat PW, the operation is halted andpractices provide a positive impact on the overall the remaining oil is abandoned. It is unknown ifinjection strategy. These effective, field proven this fact is considered when regulators formulatetools used to assess/quantify these issues are derived treatment standards for water disposal.from a decade-long PWRI joint industry project(JIP) that addresses water injection design and Increasing oil production, lowering costs foranalysis. Establishing how the engineer quantifies chemical and corrosion treatments, reducing capitalthe impact on flood and well performance will be expenditures and well intervention are parts of apresented along with field cases illustrating the rational water management policy. ‘Greener’decision-making process. operations and regulatory compliance protect a license to operate. Companies establish central waterWater Management management groups to increase capital expenditureBenefits (CAPEX) efficiency, reduce operating expenditure (OPEX) and improve environmental image.Produced water, which surfaces during oilproduction, typically contains hydrocarbons, ChevronTexaco’s (CVX) Kern River field is annaturally occurring radioactive material (NORM), example of this trend. CVX earned revenue by sellingproduction chemicals, solids and inorganic and cleaned PW from this thermal recovery project formetal salts. In early stages, water may only be a local irrigation. Petroleum Development in Omanminor component of produced fluids. As the (PDO) re-used water for irrigation and transportedreservoir depletes, PW volume increases. Water the excess to waterflood another reservoir, therebymay be injected to maintain pressure and sustain protecting local resources. These successes directlyexisting production rates, but may be subsequently resulted from focused management and use ofrecovered as PW. An example in the North Sea is technological innovations.the approximate 1:1.5 oil-to-PW ratio. The averageoil-to-water ratio over a well’s lifespan is 1:6. Water PWRI JIPs and industry alliances (supported byproduction for a gas platform runs 2m3 to 30m3 per Mobil, BP, Texaco and Chevron (MoBPTeCh))day in comparison with 2,400m3 to 40,000m3/day are examples of how industry groups collaborate on 3BUSINESS BRIEFING: EXPLORATION & PRODUCTION: THE OIL & GAS REVIEW 2005
  3. 3. Reference Section PWM. The UN’s Waste Management Technical resources for its application, new technology is Meetings, the EEC’s Convention for the Protection best utilised by active participation in industry of the Marine Environment of the North-East joint ventures. The specific areas applicable to Atlantic (OSPAR) convention, US National PW include non-conventional well completion Laboratories and non-governmental organisations and intervention, smart wells, electric (NGOs) such as the Gas Research Institute (GRI) submersible pumps and designer chemicals (see fund support for technical development. Table 2). • The implementation of a knowledge management Regulatory Framework (KM) programme facilitates internal access, learning and application of best practices. In this context, Discharge restrictions for PW in offshore fields are KM is useful in increasing the reliability and quality commonly implemented through Minerals of vendor-supplied products and services. Management Service (MMS) and US Environmental Protection Agency (EPA) regulations. In worldwide Produced Water Management practice, a prescribed range of standards ranges from 10mg to 50mg/l total petroleum hydrocarbons with Maximum impact reduction on the environment exceptions reaching to 100mg/l (regional and requires the optimal utilisation of existing technology national standards are sometimes expressed as a and resources and a complete knowledge of the monthly average, as a maximum level or as both). production process. In addition, careful management of PW waste streams both on- and offshore and the To date, emphasis has been placed on regulating the reduction of contaminant in and the volume (re- concentration of oil in PW with its determined value injection) of discharged water into the environment dependant on the analytical method used. In some are goals of integrated PWM. This practice generally jurisdictions, constraints are also imposed on: follows this series of steps: • total dissolved solid concentration (TDS); • selection of the least hazardous chemicals in order • total suspended solid concentration (TSS); to minimise PW toxicity; • copper, arsenic and zinc concentrations; • reduction in the volume of water produced; • aromatic fraction; • reuse of PW, if water quality allows (e.g., re- • concentration of specific radioisotopes; and injection for pressure maintenance); • chronic toxicity of the whole effluent. • reduction in the volume of PW to the ambient environment; and Suggested approaches for devising PWM strategies • reduction in pollutant concentrations of include various options for advancing water manage- discharged PW. ment technology within operating companies and vary regionally depending on the organisation and the Reduction in the volume of water produced at the business. Generally, there are four major elements to wellhead may be achieved by profile modification, effectively managing PW: which includes: • Compliance with environmental standards (legal • shutting down water producing wells; or best-practice based) is the most critical operational issue associated with PWM. A • isolating water producing zones in reservoir by compliance failure jeopardises a company’s setting plugs and using cement and chemical license to operate in a particular area. treatments; Compliance risks are mitigated with proactive regulatory involvement, technology applications • utilising polymer gels and relative permeability and knowledge management. modifiers; • Government agencies set regulatory standards • downhole separation; and through consultation with operators and contractors. Proactive participation by operators • use of hydro-cyclone separation followed by in regulatory forums assures their contribution to pumping oil to the surface and PWRI downhole creating solutions and provides insight to using submersible pumps regulatory direction and emerging issues. Reduction in the volume of PW discharged into • The application of technology avoids potential ambient environments is minimised by reducing the PW issues. Early application of new technology water at the wellhead. PWRI into underground may provide a short-term, competitive formations (reservoir or unusable aquifers) presents a4 advantage. By combining dedicated, internal best practice approach. PWRI offshore has become BUSINESS BRIEFING: EXPLORATION & PRODUCTION: THE OIL & GAS REVIEW 2005
  4. 4. Produced Water Management StrategyTable 2Produced Water Spectrum Production Separation Disposal/Injection Operation elements Strategy and tactics Strategy and tactics Strategy and tactics Injection wells Chemicals treatment Disposal Production wells Gravity separation Reinjection Development drilling Hydrocyclones Unconsolidated sands Improved oil recovery Gas flotation Stimulation Evolving technology Centrifuges Novel approaches Reliability and quality Filtration Best practices Evolving technology Knowledge management Specific topics Best practices – compile the current lessons learned, successes and failures (To each operational Operational trends – project expected trends and directional changes element) Technology trends – current focus areas, barriers and possible breakthroughs Filed specific – examples Business issues – main drivers and economic impact Regulatory issues – compliance, hurdles and permitting gaps General topics Technology strategy – internal and external considerations in creating a produced water (All operational elements) management (PWM) strategy and action plan Regulatory entities – global and regional players and controlling agency/agencies Joint industry projects (JIPs) – multinational organisations open to additional industry participation Economics of water management – selected examples of cost benefit of PWM actions Key technical resources – selected milestone resource documents.everyday practice in brownfields. Higher organic Issue-specific techniques meet specific conditionsmatter content of PW leads to increased potential regarding dispersion droplet sizes, solids, quantity,for plugging. PW is often warmer than seawater, energy consumption and size and weightwhich results in lower fracture volumes in the of equipment.formation and leads to a decreased injection rate.These limitations are overcome with new It is crucial to initially define which components oftechnologies and adoption of best practices. the PW have a significant impact on ambientReduction of pollutant concentrations in discharged conditions prior to devising a PWM strategy.produced water can result from these end-of-pipe Maximum reduction in environmental risk fromtreatment technologies: investment in treatment technologies is then realised. Results vary depending on field and• primary treatment equipment (e.g. skimmers) to production stages. In some cases, adjusting and protect downstream facilities from surges and optimising the use of existing platform facilities and upset conditions; installations is sufficient. The choice of technology and the implementation of best practices should be• secondary treatment equipment (e.g. coalescers based on an integrated evaluation. The evaluation and flotation units) used for the removal of small of cost-effectiveness, in terms of implementation droplets to bulk oil; and cost for a technology or practice versus the expected environmental and economic risk• polishing treatment equipment (e.g. filters, reduction, is advisable. This approach avoids hydrocyclones, stripping and filtration) to remove implementation of costly practices in situations very fine oil particles. where environmental improvement is not expected.Several other technologies have been developed Integrated planning and PW and reservoirfor use onshore. The potential application for these management are required for new field development.techniques in offshore operations continues to Prior to introducing new techniques, existingevolve. Specific limitations such as space constraints, discharges must be examined. Where possible, impacthighly variable water flow rates, corrosive and assessments should be carried out on a regional basisscaling properties of the waste streams, extended rather than ‘installation-by-installation’. The basis ofretention times, tendency to block, and high energy environmental standards should be provenrequirements, impose severe restraints on their environmental impacts of E&P activities in theoffshore utilisation. specific areas with the consideration of regional economic and environmental sensitivities. 5BUSINESS BRIEFING: EXPLORATION & PRODUCTION: THE OIL & GAS REVIEW 2005
  5. 5. Reference Section Concluding Remarks • minimise water production by subsurface disposal in non-usable zones; and Since no universal solution for PWM exists, additional experience and technology information • treat remaining production water. exchanges for PWM are needed to establish best practices and industry guidelines. In addition, Other essential elements to PWM include the regional environmental and economic assessment continuous training of personnel and a complete studies should be conducted on assets of the holding understanding of the production process (from business. The outcome of such assessments should be reservoir characteristics to final discharge). the basis for planning and designing new installations, improving existing facilities and choosing applicable Current experience provides two main options for best practices. In order to successfully minimise PWM, with re-injection and treatment with re- negative environ-mental effects of PW, integrated injection being the most promising solutions. PWM should optimise the use of existing Applied in many areas, re-injection is considered to technologies, take into consideration local conditions, be the best option for protection of the operational safety and engineering limitations and environment, especially in shallow waters or near include the following prioritised list of strategies: ecological sensitive sites. • eliminate discharges of PW to the marine Industry should continue to advance technologies environment; and improve safety of treatment chemicals. Further improvements of environmental and economic • reuse water where possible (irrigation or pressure performance in E&P activities require continuous maintenance); updates and analysis of collected data. ■6 BUSINESS BRIEFING: EXPLORATION & PRODUCTION: THE OIL & GAS REVIEW 2005

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