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October 2004

Cutting-Edge Software for Managing Gas Production and Storage Operations

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1. Goal of forthcoming initial release targeted for 1st Quarter, 2005: • Accurate prediction of performance of gas storage

reservoir/compressor/pipeline systems with a speed that allows hourly/daily scheduling of compressors for production and injection. Schedules obtained are efficient and economic.

• Given a complete database GasPal allows operations to be quickly rescheduled in response to new opportunities or unexpected changes in available equipment and/or supply/demand requirements.

• GasPal, focusing on operational planning, is a logical counterpart to Maraco’s GasTop software, which performs optimal investment planning for storage operations.

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GasPal Characteristics

• GasPal: foundation is a PC-based gas reservoir simulator.• GasPal: complex surface network may include splits, loops and

multiple offtake points.• GasPal: each of several reservoirs may have up to 5 producing

layers • GasPal: GRIDDER™ preprocessor inserts arbitrary number of

computing cells into each reservoir.• GasPal: simulates injection and production or a mixture of the two,

providing full storage scheduling flexibility.• GasPal: hourly, daily or monthly time steps accommodate short-,

mid- and long-term planning needs.• GasPal: optimizes service allocation and size of possible

compressor configurations.

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Operational Planning Scope

• Short-term operation: hourly time steps for two weeks. Useful for immediate injection/withdrawal planning.

• Mid-term planning: daily time step for one year. Useful for overall storage planning.

• Long-term production : monthly time step for 30 years. Useful for regular gas reservoir production or blowdown.

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Surface Flow Capabilities:Splits, Loops & Offtake Points

Produce against or inject with a given back pressure

Produce or inject a requested rate profile

Split flow at node Choke total flow or either flowline

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Surface Line Capabilities:Multiple Reservoirs

Choke each producing cell and/or reservoir to produce requested rate

Each cell in each reservoir may have different characteristics

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Surface Line Capabilities:Compressor Optimization

Compressor locations and sizes optimized to maximize withdrawal, injection and inventory revenues

Work is now underway on GasPal’s compressor scheduling capability

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Reservoir: Arbitrary Number Of Simulation Cells

FaultsComputing mesh generated by GRIDDER

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Reservoir:Multiple Layers

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Results From Current Development Version Of GasPal

October 2004

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Interface Layout

Surface network

Output Results

ReservoirsOfftake points

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Reservoir Output

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Flow Rate Through Each Pipe

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Pressure Drop Across Each Pipe

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Offtake Rate: Fixed Back Pressure

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Pressure: With Offtake Rate Fixed

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Bi-directional Flows

• Gas flow direction is determined by system pressure distribution

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Reverse Flow

Dictated by pressure at end nodes, flow can be reversed

Reversed flow displayed as “negative”