1. Produced water management is a major challenge for oil and gas producers that can restrict production and add significant costs if not addressed properly. 2. Strategies for produced water management must be tailored to local conditions and regulations, but generally aim to reduce water production, reuse water where possible, and dispose of remaining water in environmentally-friendly ways like reinjection. 3. Key elements of effective produced water management include reducing water production at the wellhead, maximizing reuse of produced water, treating water as needed before disposal, and complying with environmental regulations.

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 technical
Advantek 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 PW
2 friendly PWM position which comprises one of the injection impacts injector performance. Models
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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 economically
water partitioning and well testing exist. Best unfeasible to treat PW, the operation is halted and
practices provide a positive impact on the overall the remaining oil is abandoned. It is unknown if
injection strategy. These effective, field proven this fact is considered when regulators formulate
tools 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 for
analysis. Establishing how the engineer quantifies chemical and corrosion treatments, reducing capital
the impact on flood and well performance will be expenditures and well intervention are parts of a
presented 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 water
Water Management management groups to increase capital expenditure
Benefits (CAPEX) efficiency, reduce operating expenditure
(OPEX) and improve environmental image.
Produced water, which surfaces during oil
production, typically contains hydrocarbons, ChevronTexaco’s (CVX) Kern River field is an
naturally occurring radioactive material (NORM), example of this trend. CVX earned revenue by selling
production chemicals, solids and inorganic and cleaned PW from this thermal recovery project for
metal salts. In early stages, water may only be a local irrigation. Petroleum Development in Oman
minor component of produced fluids. As the (PDO) re-used water for irrigation and transported
reservoir depletes, PW volume increases. Water the excess to waterflood another reservoir, thereby
may be injected to maintain pressure and sustain protecting local resources. These successes directly
existing production rates, but may be subsequently resulted from focused management and use of
recovered as PW. An example in the North Sea is technological innovations.
the approximate 1:1.5 oil-to-PW ratio. The average
oil-to-water ratio over a well’s lifespan is 1:6. Water PWRI JIPs and industry alliances (supported by
production 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 3
BUSINESS BRIEFING: EXPLORATION & PRODUCTION: THE OIL & GAS REVIEW 2005

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 a
4 advantage. By combining dedicated, internal best practice approach. PWRI offshore has become
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4. Produced Water Management Strategy
Table 2
Produced 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 conditions
matter 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 weight
which 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 of
technologies and adoption of best practices. the PW have a significant impact on ambient
Reduction 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 from
treatment 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 reservoir
for 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, existing
evolve. Specific limitations such as space constraints, discharges must be examined. Where possible, impact
highly variable water flow rates, corrosive and assessments should be carried out on a regional basis
scaling properties of the waste streams, extended rather than ‘installation-by-installation’. The basis of
retention times, tendency to block, and high energy environmental standards should be proven
requirements, impose severe restraints on their environmental impacts of E&P activities in the
offshore utilisation. specific areas with the consideration of regional
economic and environmental sensitivities. 5
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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. ■
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BUSINESS BRIEFING: EXPLORATION & PRODUCTION: THE OIL & GAS REVIEW 2005