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Mature Assets: Learning from the Past, Planning for the Future

24 – 25 February 2014

Muscat, Oman | Al Bustan Palace

Technical Agenda

Session 1: Well and Reservoir Management

Session Chairs: Raed Bakhrji, Baker Hughes; Shaikhan Al Khadhuri, Petroleum Development Oman

Managing oil fields in the best way possible has always been in the centre of interests for various oil companies; production maintenance and optimisation, deferment minimisation, efficient monitoring of well, reservoir and facility performances, cross-function collaboration, and many other related issues, all represent the building blocks in a successful and efficient field management structure.

Best practices from worldwide fields show that effective well and reservoir management have resulted in sustainable production and reserve increase. The key success factors and challenges toward achieving effective well and reservoir management and realising high value are:

  • Integrated approach to closely monitor and control wells and reservoir
  • Integrated multi-disciplinary team with highly synchronised team actions
  • Structured processes and field reviews
  • Fast response to well and reservoir performance changes

Thus, the aim of this session is to have interactive presentations covering best practices, lesson learnt, and applied technologies that can help surface and subsurface engineers, fields owners, solutions and technology providers, and operators in management of well and reservoir in mature assets.

Session 2: Well Intervention and Artificial Lift Applications

Session Chairs: Shaikhan Al Khadhuri, Petroleum Development Oman; Siegfried Müssig, RAG

A significant portion of operating costs in brown fields is related to lifting costs and maintenance of artificial lift equipment. Often additional costs for workovers arise due to sub-optimal corrosion control, when sand production becomes an issue (unconsolidated reservoirs), or as the result of a long water flood history. Any combination of these problems can lead to premature abandonment of the field despite the fact that significant oil and gas reserves remain in the reservoir.

In order to combat this loss of reserves and valuable energy resource, a number of measures have to be taken. There are two keys to success:

  • the analysis of available technologies along the production chain, the identification of advanced materials and the development of stringent processes all directed to extend the lifetime of the equipment
  • A dedicated team from all disciplines working with the asset to create tailor-made solutions for the particular applications in the field

Mature assets suffer from limited budget. In order to free budget for production enhancement measures, routine drilling and workover activities need to be reduced through applying new ways of completing and repairing wells. Selecting fit-for-purpose artificial lift application supported by smart technology to monitor the production performance 24/7 in old wells is essential.

Thus this session is to discuss challenges and lessons learnt that should be considered by sub-surface engineers, well services team, operation and project owners to minimize cost and increase efficiency of tools.

Session 3: Field Studies and Case History

Session Chairs: Mohammed Al Salhi, Petroleum Development Oman; Mohammed Ibrahim, Schlumberger

On one hand, the discovery rate of giant fields has remarkably diminished over the past years. On the other hand, continuous technological advancement and favourable economic conditions has made redevelopment of mature oil and gas fields an attractive economical option.

Structured and thorough full field reviews, integrated with a vigilant use of technology proved to have a major impact on determining amount and location of the remaining oil. World oilfield recovery factors (under the basic infill and water flood development on average) has reached up to 35% in some environments while secondary and EOR methods appear promising and feasible under small and limited scale implementation to date.

Revitalisation of mature fields embraces multiple objectives, specifically maximising production while minimising capital expenditure and reducing the inevitable decline rate while minimising operating cost. The collective approach to meet these objectives is application of practical and focused engineering and geology tied with the introduction of new technology. Being able to accurately quantify the amount of oil left, the recoverable amount and finding the tools/methods to achieve this are key activities.

Since the beginning of the modern age of oil and gas, technology has played a fundamental role in supporting the efficient production of hydrocarbons. Basic technological applications like 3D seismic, horizontal well drilling, and hydraulic fracturing had moved enhanced recovery and unconventional resources from a subtext of domestic development to major players.

Around the globe, many case studies offer insight on how such opportunities were identified, studied and evaluated, and executed resulting in giving old ageing fields an extended new life. Success are expressed in forms like arresting the field decline rate, kicking off new projects like secondary or EOR, and identifying more resources linked to the existing field.

In most of these redevelopments, an integrated multi-discipline study is always crucial in understanding and redefining the remaining potential to be targeted. Rock and fluid properties and phase behaviour will then determine the best approach in methods and technologies to target the remaining reserve and be able to efficiently and economically optimise the field value.

Session 4: Redevelopment of Mature Assets

Session Chairs: Ali Ahmed Jama, Schlumberger, Badar Al Kharusi, Petroleum Development Oman

As producing oil and gas reservoirs accelerate and big fields get harder to find, the effort intensifies to recover more of what has already been found. Redeveloping of existing mature assets, for example changing the reservoir recovery strategy from primary depletion to secondary depletion or from secondary to tertiary present a huge target of opportunity; even a modest increase in average recovery will add a significant supply.

Recovery and production from these fields can be achieved by infill drilling, stimulation interventions, production optimisation through artificial lift mechanisms, and by reducing water and sand production. Remediation and redevelopment options can therefore slow the decline of a mature asset and enhance its value.

Many of the mature assets were completed with single lateral (often vertical with some horizontal) to delay, and minimise the potential for early gas breakthrough and/or water coning.  However in recent years, significant improvements in well performance led to the redevelopment of these single lateral wells and the evolution of maximum reservoir contact (MRC) wells, also known as complex or multilateral wells. Designing, completing, and operating of these MRC wells brings significant challenges when considering redevelopment of mature assets.

Another area of significant advancement in recent years with regard to redevelopment of mature fields is the area of subsurface-surface integration and integrated asset modelling. This calls for the development of integrated asset model that increases the transparency back to the detailed subsurface depletion plans while honoring deliverability and surface constraints. Another added value of the integrated asset management is the ability of production planning and what if/look ahead scenarios planning, leading to debottlenecking and rejuvenation of existing facilities. This session will stimulate discussion and knowledge sharing in the above areas.

Session 5: Production Operations and Efficiency Management

Session Chair: Ali Ahmed Jama, Schlumberger

With large number of oil and gas fields becoming mature, the upstream industry is facing a new challenge of how to increase, or at least stabilise production while maintaining reserves at the same time, coupled with hostile and remote environments, and ageing facilities.

The focus on production operations is shifting from mundane and manual processes to detailed analysis and optimization to understand and determine the root causes of operational problems. This requires connecting operational data to engineering models, enabling predictive diagnostics, so teams can understand the impact of changing conditions, and take smart actions to prevent production losses.

With mature assets, the production discipline must deal with tens of years of production history, cope with an overload of moment by moment data from instrumented wells and platforms, predict when it must take action to avoid downtime and losses, and operate an asset for 30 years or more—safely and profitably. To effectively manage operations, optimise production and at the same time manage costs, it is imperative for the production team to move from a reactive mode to a more proactive mode of operating.

A major trend having positive impact on producing assets is automated operations. With pressures on staffing resources and costs, more and more focus is being placed on instrumentation and automation to augment oil and gas well operations, control, maintenance, and optimisation through digital oilfield initiatives. This session will also highlight the latest applications of digital oilfield technologies in mature assets.

Session 6: Well and Facility Integrity Management

Session Chairs: Steve Matthews, PETROFAC

In the context of this workshop, the term mature assets will often include production facilities that are either approaching or exceeded their original design life. The drive to enhance recovery from such assets means that such facilities will be required to remain operational for a significant period of time into the future—in some cases for multiples of the design life.

The ageing infrastructure (required to deliver the enhanced recovery) presents the industry with a significant and growing challenge. Ageing is typically characterised by time-dependent degradation threats, such as corrosion. When combined with, often severe, process and external environmental conditions, this can present operators and duty holders with numerous ‘integrity threats’ to be addressed and a range of associated hazards due to the potential loss of containment events. These threats and hazards are exacerbated if appropriate integrity management practices and systems are not in place.

This session will focus on discussions of:

  • The key threats to mature wells and facilities integrity, industry experience and best practice technologies for the mitigation, and/or remediation of these threats.
  • Best practices for mature wells and facilities integrity management, including life extension strategies, risk management, and data management/analysis.

Session 7: EOR—The Frontiers

Session Chairs: Xing Zhang, Schlumberger; Mohammed Al Salhi, Petroleum Development Oman

EOR is an important part of improving total production, particularly for ageing reservoirs. Asset managers and field planners consider various EOR methods as part of the initial field development plan. Yet questions remain with respect to the technical and economic viability and ‘how much’, ‘where’, ‘what’, etc. With a range of technologies, typically including steam flood, water/gas flood injection, and hydraulic fracturing, EOR from screening, pilot studies to full field implementations is available.

The screening process begins with gathering as much reservoir data as possible and developing a coherent package to compare with the screening criteria for various EOR methods. After narrowing the choices, the evaluation moves into the laboratory to investigate rock and fluid properties, and to conduct flow studies. Chemical EOR can be evaluated with a single-well wireline service that yields results in a matter of days. Engineers and geoscientists use the available data to develop updated static and dynamic reservoir models, and to simulate the effects of different EOR methods in order to choose the optimum one.

Pilot studies reduce uncertainty and operating risk, helping to plan a way forward for large-scale developments. Design of pilot projects provides injection, production, and surveillance equipment and facilities. Knowledge of EOR pilots and operational experience can help accelerate EOR projects with specific technologies for well placement, construction, completion, monitoring, and production.

An increasingly detailed reservoir model can be extended from the pilot to the scale of the development area with full field implementations. The final drilling and completion activities, as well as the surface facilities and transport design are determined by this model. Production monitoring from the ongoing pilot can be used to optimise the expanded operations to maintain planned production. This can be achieved by integrated project management.

Advanced software and services help to plan reservoir strategy and recovery with increased confidence for maximum return. Major unknowns, such as formation heterogeneity, are evaluated using multiple iterations of the simulator with different model parameters. By comparing expected supply costs and project economics with the base case of continued production without (EOR), the reservoir strategy and recovery schedule can be optimised. If the simulation indicates that the project meets technical and financial requirements, then it can be used to design the next stage—pilot projects. Sophisticated reservoir simulation software helps select the best EOR technique for the unique properties of the reservoir, and design strategies to overcome technical challenges. An accurate reservoir model is important for understanding the dynamic behaviour of downhole fluids and for optimising production. Three-phase, 3D simulations model for all modern EOR technologies is available, including CO2 injection, water and miscible-solvent gas injection, and the widest variety of thermal recovery processes.

EOR, particularly in mature reservoirs, is likely to face geomechanical challenges to maintain ageing assets integrity, including wellbore stability in infill drilling through depleted zones, caprock sealing, completion integrity, water production prediction, sanding management, reservoir compaction/expansion, and ground surface subsidence/uplift. 4D reservoir geomechanics through coupled reservoir geomechanical modelling can provide the solution for these challenges. In addition, optimal design for hydro-fracture, steam flooding, and water/gas flood injection can be achieved by 4D reservoir geomechanical studies.

Session 8: Produced Water Management

Session Chairs: Indranil Chatterjee, NALCO Champion; Mohammed Ashraf, FMC TECHNOLOGIES

Increase water production is a major challenge for oil and gas operators worldwide. In some mature assets, water production has exceeded the amount of oil being produced.

With global average water cuts reaching an approximate 75% and rapidly increasing, the requirement of produced water systems have become a critical part of all production facilities worldwide.

Many different types of technologies can be used to treat produced water; however, the types of constituents removed by each technology and the degree of removal must be considered to identify potential treatment technologies for a given application. For some types of produced water, more than one type of treatment technology may be capable of meeting the contaminant removal target; and a set of selection criteria must be applied to narrow down multiple treatment options.

Often the presence of oilfield microorganisms such as sulphate reducing or acid producing microorganism leads to unwanted H2S production, microbiologically influenced corrosion (MIC) and subsequently souring or asset corrosion issues. Due to this, water cycle management and properly designed microbial control programmes for all water sources including injected water or produced water, are also required. Because the microbial challenges and environmental parameters of these water sources vary, different microbial control strategies and treatments are required for each source.

Thus, the aim of this session is to have interactive presentations covering new strategies, structures, applications, and technologies that should be considered by project owners, developers, and operators in management of produced water in mature assets.