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Managing Reservoir Assets
- Dr M R Srinivasan, Professor, Department of Petroleum Engineering and Geoscience, University of Petroleum and Energy Studies
A sound management practice in reservoir assets consists of setting goal, developing and implementing plan, monitoring and evaluating performance and revising necessary unworkable plans, without jeopardising the ultimate goal of asset management to maximise economic benefits by optimising recovery along with minimised CAPEX and OPEX. The article presents sound reservoir management practice in developing new field, revitalising a mature oil field to enhance economics in projects at various stages of the reservoir life cycle.

The life cycle of a reservoir starts with exploration that leads to discovery followed by delineation of the reservoir, development of the field and finally abandoning the same.

Reservoir asset management and processes exemplify sound reservoir management practice in developing a new field, revitalising a mature oil field. Reservoir performance analysis supported by economic results is executed at various stages of the life cycle. A sound management practice in reservoir assets consists of setting goal, developing and implementing plan, monitoring and evaluating performance and revising necessary unworkable plans, without jeopardising the ultimate goal of asset management to maximise economic benefits by optimising recovery along with minimised CAPEX and OPEX.

The general management of Reservoir Assets is triggered by the following business drivers:
1. Volatility of Oil Prices
2. Changes in Geographical Emphasis
3. Rapid Advancement in Technology
4. Environmental and Safety Requirements

The current volatility in oil prices seems to continue over the medium term which lays emphasis on low cost production of hydrocarbon. Cost cutting is being done by applying new technology and new business models. There are various strategies to manage the reservoir assets. The relative importance of these strategies will vary from asset to asset and from time to time with in the development life cycle.

Financial Strategy of Integrated Reservoir Management
The principal financial strategy of managing the reservoir asset is -- maximise the cash flow subject to capital and operating budgets and safeguarding funds flow from the existing investments.

The primary key output of reservoir management is the protection of funds flow from existing investments in terms of wells and infrastructure. The secondary key output is to generate the options and strategies for production optimisation from the reservoir assets. These takes care of both the short term (maximising production) and long term increase of reserves and manage/defer abandoning.

The asset management can predict generation of funds and decide allocation to new strategies and options in implement based on availability of capital, cash generation requirement and risk appetite. With a two pronged approaches on cost reduction and enhanced personnel productivity, the cost base can be kept minimum. Cost reduction is achieved through lowering cost of manpower and IT. The personnel productivity is enhanced by adopting staffing practices. Increasing the efficiency on day to day basis, reservoir management allows more resource allocation to identified investment opportunities.

Implementing Integrated Reservoir Management
The following strategy is applied to achieve the re-engineering of the reservoir management practice:
  • Develop culture of learning with a consistent focus on technology pertinent to the asset’s goals.
  • To achieve continuous improvement establish performance measures.
  • Formulate an integrated, multi-skilled engineering team, which forms the basis of the successful reservoir asset management.
This calls for widening of the knowledge to encompass other disciplines and skills, promoting learning culture which generates the knowledge of available resources leading to soliciting the most appropriate solutions.

A prudent application of infil - drilling and improved. Hydrocarbon recovery methods intertwined with, systematic data acquisition and management, which allow detailed tracking of production and injection are a must for combating production decline and managing reservoir energy.

Use of 4D seismic (time lapse 3D seismic) in managing the reservoir assets is slowly becoming the norm of the day. New developments use this (4D) along with reservoir start up and appraisal to strategise the development and manage the aged fields & use it to look into balance in reserves and prolonged field life.With the help of 4D seismic data, analysis and interpretation, the infil target wells to be drilled can be planned.

They also can provide a strong support for interpreting well behaviour in terms of OWC (Oil Water Contact).

They can be studied for performance prediction by integrating to understand water coning etc.
Real-time Reservoir Management
This is another emerging concept in managing reservoir asset discipline. In this, the emphasis is shifted from mad rush to and gas (natural resources) to be extracted, to a controlled process, where production can be monitored and optimised. This will transform the core competenc y of oil majors i.e., reser voir asset management.

Real-time reservoir asset management demonstrated the use of new technology like Nanotechnology and produce hydrocarbons at lesser cost with minimum personnel intervention, hence maximising efficiency and enhance revenues. The true real time reservoir management and cont ro l combines the various connected disciplines and improve the efficiency of data utilisation and sharing.

The key drivers for real-time reservoir asset management are the four stages in the development:
• Exploration: where the reservoir structure and contents are investigated but not defined well.

• Delineation: where the assessment of size and extent are being done.
• Development: During this phase the reservoir being well understood and the production is at peaking level.
• Maturity: Stage at which the reservoir is well understood while the quality of reserves changing due to depletion trend.

This is influenced by various issues like technical, logistics, HSE and economic. The top most priority in this is identifying and evaluating the factors which control the flow of hydrocarbon in reservoirs. This involves in getting the effects of capillarity, gravity, rock heterogeneity, the phase changes and chemical reactions that are typical with multiphase flow.

The technical challenges like modelling of Pore scale processes, complicated heterogeneity in few reservoirs and macroscopic flow instabilities and large scale modelling of EOR, do exist.

Once the reservoir is reasonably modelled and characterised, we can predict how the possible modifications in production / field development strategies will affect hydrocarbon production rate and recovery. These predictions can be tested under logistic and economic constraints. We may have to evaluate the safe design limits for pipe lines and other production facilities especially for planning for combating Health & Safety hazards. While the design of production facilities involves being able to predict, it should take care of handling Asphaltenes, Wax, H2S, CO2 corrosion etc. and also handling increasing water production. Such production scenarios are obtained from the reservoir model which in turn is based on thorough and accurate understanding of fluid composition and the rock chemistry.