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Additional Options
By selecting from the wide range of add-on options, you can tailor an ECLIPSE reservoir simulation solution to your project to enhance the scope of your simulation studies.
Local Grid Refinement
The local grid refinement option allows enhanced grid definition near wells and faults. Local models in three dimensions can be radial, unstructured, or Cartesian; in two dimensions, they can be radial or unstructured. Local models can have more layers than the global model, with the transmissibilities between the local models and the global model computed automatically.
The grid-coarsening options allow you to reduce simulation cycle time and maintain precision by amalgamating cells in regions of the field where accuracy is not as critical while maintaining the necessary precision where required.
Gas Lift Optimization
The Gas Lift Optimization facility determines how much lift gas to allocate to each well in order to meet well, group, or field production targets. If production targets cannot be met, the Gas Lift Optimization option determines how to make the best use of the existing lift gas resources by allocating lift gas preferentially to the wells that can make the best use of it.
The Gas Lift Optimization facility solves the following problems:
- Optimizing gas lift to individual wells
- Optimizing gas lift within a group of wells
- Optimizing gas lift within a simple network
Gas Field Operations
The Gas Field Operations option contains a set of facilities designed to model gas field production constraints and operations. The principal features in this set include
- seasonality profile
- adjustment of DCQ to allow for swing
- control and output of sales gas rate
- estimation of delivery capacity
- automatic compressor operation.
Gas Calorific Value-Based Control
The Gas Calorific Value Control option allows you to control the mean calorific value of gas produced from the field, while also controlling the gas production rate. Production rate targets are handled by guide rate group controls. ECLIPSE automatically adjusts the guide rates so that the produced mixture has the required mean calorific value. As an alternative to controlling the gas production rate, you may elect instead to control the overall energy produced.
Geomechanics
The Geomechanics option provides the ability to simulate compaction processes that are not available with the ECLIPSE standard rock compaction option. Coupling the geomechanical rock stress calculation with the fluid flow has the following benefits:
- The prediction of subsidence and compaction in a reservoir is improved.
- Modeling of fluid flow is improved through stress-dependent permeability and Biot's constant.
- Stress, traction and displacement boundary conditions can be set on external as well as internal surfaces.
- The grid for the stress calculation is the same grid that is used when calculating fluid flow.
- Rock mechanical properties are input on a grid-by-grid basis.
- Plastic yield function parameters and permeability/Biot constant versus stress tables are set in user-defined geomechanical regions of the grid.
Coalbed Methane
The naturally occurring methane within coal seams can in some cases be economically produced using oilfield technology. In these coalbed methane projects, wells are drilled into the coal seam to produce gas. Considerable reserves of this unconventional natural gas are present in many parts of the world.
The coal beds are naturally fractured systems with the gas adsorbed into the coal matrix. Primary production occurs by initially dewatering the natural fractures and thus reducing the pressure in the fracture system. The reduced pressure in the fractures allows gas desorption from the surface of the coal to the fracture. Gas diffuses from the bulk of the coal towards the fracture surface.
For dual porosity, the Coalbed Methane option uses a modified Warren and Root model to describe the physical processes involved in a typical coalbed methane project. More...
Networks
The Network option is designed to provide groups of wells with variable tubing head pressure (THP) limits that depend on the groups' flow rates according to a set of pipeline pressure loss relationships. The option calculates the well THP limits dynamically by balancing the flow rates and pressure losses in the network.
Reservoir Coupling
The Reservoir Coupling facility provides a means of coupling a number of separate simulation models to account for constraints on overall production and injection rates, and optionally the sharing of a common surface network.
Use scenario
The following is a typical situation in which the Reservoir Coupling facility would be useful. Imagine you are responsible for an area that contains a number of separate independent reservoirs. For each reservoir, you have a separate simulation model, which you have used to history-match the reservoirs independently. The simulation models may have different characteristics. For example, some may be 3-phase while others are 2-phase. One model may use the Vertical Equilibrium option, while the others use dispersed flow. There are now plans to produce these reservoirs into common surface facilities, and constraints on overall production and injection rates must be observed. The Network model may also be used to determine the pressure constraints in a common surface network linking the reservoirs.
Flux Boundary
The Flux Boundary option allows ECLIPSE simulation runs to be performed on a small section of a field using boundary conditions established from a full field run. Flow across the boundary of the reduced field is written to a FLUX file at each mini-timestep of the full field run.
The FLUX file is then read during the reduced field run to generate the appropriate boundary conditions. Timesteps of the reduced field run may be quite different from those of the full field run.
Environmental Tracers
The Environmental Tracers option enables the modeling of contaminants and other substances as they flow within a host water, oil or gas phase.
The Passive Tracer Tracking model enables you to track up to 50 tracer substances within a single model.
The Environmental Tracer option extends the modeling to account for adsorption of the tracer on to the bulk rock, decay of the tracer over time, and molecular diffusion of the tracer. It is possible to model adsorption, decay, and diffusion within a single tracer.
Pseudo-Compositional
The standard ECLIPSE black-oil model assumes that the saturated hydrocarbon fluid properties are functions of pressure only and disregards any compositional dependence in the saturated fluid PVT properties. As a consequence, when dry gas is injected into a condensate below its dewpoint the gas continues to revaporize liquid at a rate governed only by the ambient pressure. The vapor saturates over a zone whose thickness is of the order of one grid block-in particular all the liquid in the vicinity of the injectors evaporates rapidly. Results obtained with fully compositional simulation models suggest that liquid saturation profiles would vary more slowly with increasing distance from gas injectors.
The Pseudo-Compositional option extends the black-oil, two pseudo-component model to take into account fluid property changes occurring during gas injection. A number of extensions of the black-oil model to treat compositional effects arising during gas injection have been reported in the literature, and all methods hinge on extending the fluid property treatment so that the saturated fluid properties depend not only on pressure but also on an additional parameter that characterizes compositional changes in the reservoir liquid and vapor phases at constant pressure.
EOR Foam
The EOR Foam option can be used in a number of ways to increase the production from an oil reservoir. The foam acts to decrease the mobility of gas, slowing the breakthrough of injected gas or reducing the production of gas cap gas.
The ECLIPSE Foam model does not attempt to model the details of foam generation, flow, and collapse. In this model we assume the foam is transported with the gas phase, and hence we model the foam by a tracer in the gas phase that accounts for adsorption on to the rock and decay over time.
EOR Polymer
The main objective of polymer injection during water flooding of oil reservoirs is to decrease the mobility of the injected water. This decrease results in a more favorable fractional flow curve for the injected water, leading to a more efficient sweep pattern and reduced viscous fingering. Certain plugging effects within highly permeable layers may also occur and result in the diversion of the injected water into less permeable zones of the reservoir.
EOR Solvent
An injected fluid sets up a miscible displacement if there is no phase boundary or interface between the injected fluid and the reservoir oil. A miscible displacement has the advantage over immiscible displacements such as water flooding of enabling very high recoveries. An area swept by a miscible fluid typically leaves a very small residual oil saturation.
The ECLIPSE solvent option allows you to model gas injection projects without going to the complexity and expense of using a compositional model. The solvent extension implements the Todd and Longstaff empirical model for miscible floods and is flexible enough to model a wide range of gas injection schemes.
EOR Surfactant
Most large oil fields are now produced with some type of secondary pressure maintenance scheme, such as water flooding. Water flooding can increase recovery from around 1% to the 20-40% range. The remaining oil can be divided into two classes, residual oil to the water flood, and oil bypassed by the water flood. A surfactant flood is a tertiary recovery mechanism aimed at reducing the residual oil saturation in water-swept zones.
A surfactant offers a way of recovering the residual oil by reducing the surface tension between the oil and water phases. A very low oil-water surface tension reduces the capillary pressure and hence allows water to displace extra oil. If it is possible to reduce the surface tension to zero, then theoretically the residual oil can be reduced to zero. In practice, the residual oil to even high concentrations is unlikely to lead to 100% recovery of swept zones.
The ECLIPSE Surfactant option does not aim to model the detailed chemistry of a surfactant process, but rather to model the important features of a surfactant flood on a full-field basis.
Wellbore Friction
The Wellbore Friction option models the effects of pressure resulting from friction in the well tubing along the perforated length, and between the perforations and the bottomhole reference point of the well. The facility is primarily intended for use with horizontal and multilateral wells, in which frictional pressure losses may be significant over the horizontal section of the wellbore and in the branches.
In horizontal wells, the perforated section may extend over many hundreds of feet. The frictional pressure drop over this length may have a significant effect on the behavior of the well. The pressure in the wellbore towards the far end of the perforations (in other words, away from the wellhead) will be higher than the pressure at the near end, so the drawdown will vary over the perforated length. This may cause the productivity per unit length of perforations to fall off towards the far end. Furthermore, the lower wellbore pressure at the near end of the perforations may cause localized water or gas coning to occur in this region, thus reducing the effectiveness of the horizontal well in overcoming coning problems. It is therefore important to consider the effects of frictional pressure losses when deciding on the optimum length and diameter of a horizontal well.
Multi-Segmented Wells
The Multi-Segmented Well model provides a detailed description of fluid flow in the wellbore. The facility is specifically designed for horizontal and multi-lateral wells, although it can of course be used to provide a more detailed analysis of fluid flow in standard vertical and deviated wells. As in the standard well model, the equations are solved fully implicitly and simultaneously with the reservoir equations, to provide stability and to ensure that operating targets are met exactly.
Unencoded Gradients
The Unencoded Gradients option computes gradients of the solution (for example, pressure in a well) with respect to various property parameters defined by the user, such as horizontal permeability in a layer.
The ECLIPSE SimOpt model calibration software program uses the gradients computed by the simulator to achieve an efficient regression during a history match or sensitivity analysis, varying the property parameters via modifiers.
Parallel ECLIPSE
The Parallel ECLIPSE option allows the simulation of a single dataset to be distributed across a number of processors. This allows large simulations to be carried out in a shorter time than would normally be the case with the standard simulators. ECLIPSE is optimized to provide the shortest time to solution, and consequently tailor the number of domains and hence the linear solver to the number of available processors. This has a number of consequences. Firstly, the results obtained on different numbers of processors will agree to engineering accuracy, not to machine accuracy. Secondly, the scalability is poorer than one might expect, as the linear solver becomes less efficient as we progress to larger numbers of processors.
You can change the number of processors at restarts depending on the resources available, using flexible restarts.
Open-ECLIPSE Developer's Kit
The Open-ECLIPSE Developer's Kit enables ECLIPSE to be controlled by and communicate interactively with other applications. Although ECLIPSE is primarily used in a batch stand-alone mode controlled solely by the contents of the input data file, there are many situations in which it would be advantageous to have ECLIPSE controlled by another software application.
Examples include the requirement to have ECLIPSE tightly coupled to a surface gathering system model or a specialized production optimization application. It could also be useful to couple ECLIPSE to an interactive controller, to allow you to view the current status of the simulation and make well management decisions during the course of the run.
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