IPM Products

Petroleum Experts (Petex) develop the Integrated Production Modelling (IPM) software suite.

IPM models the complete oil or gas production system including reservoir, wells and the surface network as an integrated unit.

The IPM suite of tools: GAP, PROSPER, MBAL, PVTP, REVEAL and RESOLVE can be run together seamlessly, allowing the engineer to design complete field models. The models can include the reservoir tanks, all the wells and the surface gathering system. IPM can model and optimise the production and the water or gas injection system simultaneously. With the Reservoir, Wells and Complete Surface Systems model completed and the production history matched, the production system can be optimised and production forecasts run.

The unique global optimisation approach permits the engineer to determine the optimum setting to maximum production or revenue, taking account of all constraints that are set in the system. These results can then be used to implement adjustments at the field level to achieve the optimisation goals.

There are literally several thousand fields worldwide having their production managed and optimised using IPM. All common naturally flowing well configurations, including multi-lateral, whether naturally flowing or with artificial lift can be modelled and optimised together.

With the use of RESOLVE and OpenServer the IPM approach has been extended to connecting the PETEX software to third party software such as Reservoir Simulators and Process Simulators. These products form a suite of complementary tools assisting engineers to improve their reservoir simulations by describing and modelling a production system more accurately.


PROSPER is a well performance, design and optimisation program for modelling most types of well configurations found in the worldwide oil and gas industry today. PROSPER can assist the production or reservoir engineer to predict tubing and pipeline hydraulics and temperatures with accuracy and speed. PROSPER’s sensitivity calculation features enable existing well designs to be optimised and the effects of future changes in system parameters to be assessed.

PROSPER is designed to allow building of reliable and consistent well models, with the ability to address each aspect of well bore modelling viz; PVT (fluid characterisation), VLP correlations (for calculation of flowline and tubing pressure loss) and IPR (reservoir inflow). By modelling each component of the producing well system, the User can verify each model subsystem by performance matching. Once a well system model has been tuned to real field data, PROSPER can be confidently used to model the well in different scenarios and to make forward predictions of reservoir pressure based on surface production data.

With PROSPER detailed flow assurance can be studied at well and surface pipeline level. PROSPER provides unique matching features which tune PVT, multiphase flow correlations and IPR to match measured field data, allowing a consistent model to be built prior to use in prediction (sensitivities or artificial lift design).

Production System Analysis

  • Inflow performance models (IPR)s
  • Horizontal well with pressure drop in well
  • Multi-layer with pressure drop in well
  • Hydraulic fracture
  • Time dependant IPR
  • Multi-laterals
  • Dual porosity
  • Outflow
  • Pipe stability calculations
  • Proprietary well pressure drops model –
  • PVT – Oil, Gas, Condensate – Black Oil or Fully Compositional
  • Tubing and pipeline quality check
  • Sensitivity analysis

Well Types

  • Gas, oil, water, condensate, steam, injection wells
  • Naturally flowing
  • Artificially lifted
  • Multi-layer
  • Multi-lateral
  • Angled and horizontal

Artificial Lift System Analysis and Design

  • Electric Submersible Pump – ESP
  • Gas Lift
  • Hydraulic Pumps – HSP
  • Progressive Cavity Pumps – PCP
  • Jet Pumps
  • Beam Pumps – Rod
  • Design new artificial lift systems
  • Verify the efficiency of existing system


GAP is a multiphase oil and gas optimiser tool that models the surface gathering network of field production systems. When linked with the well models of PROSPER and reservoir models of MBAL a full field production optimisation and forecast can be achieved. GAP can model production systems containing oil, gas and condensate, in addition to gas or water injection systems.

GAP’s powerful non-linear optimisation engine allocates gas for gas lifted wells or sets wellhead chokes for naturally flowing wells to maximise revenue or oil/gas production while honouring constraints at any level in the system.

Multi-well optimisation for artificially lifted and naturally flowing production networks:

  • Surface gathering system models with constraints
  • Looped networks
  • Gas and condensate gathering systems
  • Oil and water gathering systems
  • Injections networks
  • Compressor modelling
  • Pump modelling



Optimisation of gathering system against constraints:

  • Fast and robust Global Optimisation algorithm using non-linear programming (NLP) which has been recognised in the industry as best in class.
  • Wellhead chokes can be set, compressors and pumps optimised, and gas for gas lifted wells allocated to maximise production
  • Multiple Flowlines
  • Multiple Separators
  • Unlimited number of nodes – wells, reservoir, etc.
  • Field optimisation studies with mixed systems (ESP, GL, Naturally Flowing, PCP, Jet and Rod Pumps)
  • Optimise production forecasting

Pipeline Flow Assurance Studies

  • Reservoir Management
  • Models injection system performance, using MBAL or other numerical reservoir models
  • Advises on wellhead chokes settings to meet reservoir management targets

Fully Compositional from the Reservoir to the Process side

Easy to use graphical interface for drawing system network (using icons for separators, compressors, pipelines, manifolds and wells, inline chokes and reservoir tanks)


Efficient reservoir development requires a good understanding of reservoir and production systems. MBAL helps the engineer better define reservoir drive mechanisms and hydrocarbon volumes. This is a prerequisite for reliable simulation studies. MBAL is commonly used for modelling the dynamic reservoir effects prior to building a numerical simulator model.

MBAL contains the classical reservoir engineering tool and has redefined the use of Material Balance in modern reservoir engineering.

For existing reservoirs, MBAL provides extensive matching facilities. Realistic production profiles can be run for reservoirs with or without history matching.

MBAL is an intuitive program with a logical structure that enables the reservoir engineer to develop reliable reservoir models quickly.

Reservoir Engineering Tool

  • Material Balance
  • Monte Carlo Simulator
  • Decline Curve Analysis
  • 1D model
  • Multi-Layer
  • Tight Gas

Material Balance

  • This incorporates the classical use of Material Balance calculations for history matching through graphical methods (like Havlena-Odeh, Campbell, Cole etc.). Detailed PVT models can be constructed (both black oil and compositional) for oils, gases and condensates.
  • Furthermore, predictions can be made with or without well models and using relative permeabilities to predict the amount of associated phase productions.
  • Multi Tank Variable PVT with Depth
  • Determine Components of Reservoir Energy
  • Visualise the Parameters that Impact Performance

Forecast Well and Reservoir Performance

  • Forecast Using Rate Schedule or Well and manifold pressure schedule
  • Set well and global constraints:
  • At well and field level
  • Determine when wells will water out
  • Forecast pressure decline, producing GOR
  • The long term effects of completion decisions on compression, gas/water injection, gas recycling


  • Black oil
  • Fully Compositional
  • Compositional Tracking


RESOLVE has been developed as a master controller to communicate and control the link between Reservoir Simulators, Process Simulators, other third party software, as well as client proprietary tools and the IPM suite.

RESOLVE: Features – Main

  • Application to connect and run integrated models comprising of an unlimited number of applications
  • Hyper-threaded
  • Strong parallelisation of solver algorithm wherever this is possible
  • Makes use of local (multi-processor) and network (remote machine) resources
  • Any topography of connected system is allowed
  • No fixed concept of upstream or downstream
  • Entirely open architecture
  • User connections can be developed (many examples of this)
  • The application as a whole can be controlled from an external controller
  • In addition to our optimisers, users can use their own external optimiser (see below)
  • Models can be run predicatively or at a snapshot in time

RESOLVE: Reservoir Coupling

  • Default scheme does not use Newton coupling (although available as an option)
  • Iteration between reservoirs and GAP is possible, but is rarely required with the default algorithm
  • Tested extensively on fields throughout the world
  • Adaptive time-stepping also available

RESOLVE: Surface Network Implementation

  • optimisation
  • connection to material balance (MBAL)
  • production AND injection systems in a single license
  • distribution of network models and parallel optimisations over a network


  • Thermodynamic consistency between applications in an integrated model is ensured Black-oil models can be mixed with fully compositional models

RESOLVE: Event/well management

  • Comprehensive event / well management scheme
  • entirely open-ended
  • Any variable of any application in an integrated system can be interrogated to perform (if … then … action) directives
  • An action does not have to apply to the application in which the event took place
  • Actions can be complex
  • g. well ranking based on an associated variable (e.g. water cut, potential, revenue calculation)
  • g. switching from HP to LP separation while simultaneously changing compressor curves
  • This is all available through a simple user interface
  • Very complex management can be performed through a VBA script, hence the management is completely open ended
  • Schedules embedded in the client applications will be honoured in a Resolve run

RESOLVE: Optimisation

  • Two levels of optimisation
  • Non-linear optimisation in GAP
  • Successive linear optimisation in RESOLVE
  • Optimisation problems can be distributed over ALL applications in an integrated model
  • RESOLVE determines most efficient iteration scheme to calculate derivatives
  • Tested extensively on real-field cases

RESOLVE: version control

  • Tight integration with Petroleum Experts ModelCatalogue
  • RESOLVE models can be checked in and out
  • All associated models from the client applications are also checked in and out

RESOLVE: link to Excel

  • Dynamic linking (drag and drop) to Microsoft Excel for:
  • Calculation
  • Reporting
  • Stream splitting / manipulation


  • All application ‘instances’ can be added to the framework through a simple ‘drag-and-drop’ interface
  • Wizards are available for common tasks, e.g.
  • Voidage replacement
  • Configuration tasks
  • Run-time data from client applications (e.g. diagnostics) is channelled through the RESOLVE GUI

RESOLVE: Reporting

  • Comprehensive and dynamic
  • Results appear dynamically during the run, allowing instant access to the results and improved trouble-shooting
  • Optimisation and loop iteration results are stored separately at every timestep
  • Any variable of any client application can be added to the ‘standard’ variables always displayed by RESOLVE.
  • The structure of RESOLVE makes it very straight forward to link – through a DLL – a particular engineering tool. RESOLVE uses OpenServer, which means a user can write own link to RESOLVE as well as use the standard ones.

Link to third party software:

Process Simulators

  • UniSim – Honeywell
  • Hysys – Aspentech
  • Pro II – Schneider Electric

Reservoir Simulators

  • Eclipse 100 – Schlumberger Black Oil reservoir simulator
  • Eclipse 300 – Schlumberger Compositional reservoir simulator
  • IMEX – CMG Black Oil reservoir simulator
  • GEM – CMG Compositional reservoir simulator
  • Pumaflow – IFP reservoir simulator
  • VIP – Halliburton reservoir simulator
  • Tempest – Roxar
  • tNavigator – Rock Flow Dynamics

Tables/Statistical Tools

  • Crystal Ball – Oracle
  • @Risk – Palisade

Dynamic Multiphase Simulators

  • LedaFlow -Kongsberg

Proprietary to clients

  • PSim – ConocoPhillips reservoir simulator
  • MoReS – Shell reservoir simulator
  • GigaPowers – Saudi Aramco reservoir simulator
  • Chears – Chevron reservoir simulator


REVEAL is designed to study specialised near well bore effects and assess their impact on the production from the reservoir.

Most reservoir groups within the oil and gas companies are carrying out specialist studies in areas such as

  • Thermal and mobility studies – injectivity and production
  • Production chemistry
  • Scaling
  • Souring
  • Solids and Sanding
  • Thermal and hydraulic fracturing
  • Steam injection

These studies are often being carried out isolated from the reservoir simulation model. The key role for REVEAL is allow these specialist studies to be integrated with the reservoir simulation models – Eclipse, VIP, etc. – to evaluate the impact on production. REVEAL enables the corporate reservoir simulation model to be used and the effects of these specialist studies to be integrated.

As an illustration: What is the impact of injecting cold water – at sea temperature – into a reservoir at 90 to 110 Deg. C. An injectivity test will often show good injectivity. When the injection system is tied in, the ability to inject the water deteriorates dramatically with time. The assumption can be that there is plugging. The reality is that the injected cold water is cooling the reservoir and there is a mobility reduction at the reservoir level. This is a very typical problem found today and is most pronounced in the Deep Water fields.

Specialist studies in the above areas are often carried out in isolation. REVEAL is a tool that allows these, often isolated studies, to be evaluated in context of the complete production and reservoir system. REVEAL can bring together the studies of the production chemist, fracturing specialists, sanding and thermal effects…

REVEAL can therefore be considered as a tool for integrated reservoir and production studies.

Injection of chemicals or fluids at non-reservoir temperature can have significant effects on fluid mobilities and therefore subsequent injectivity and oil production.

Specialist Model:

  • Thermal and Hydraulic Fracturing
  • Steam
  • Solids
  • Mobility Control
  • Phase Emulsification
  • Water Chemistry

There is a single interface to all functionality, including:

  • Data input and validation
  • Post-processing
  • 3D graphic visualization
  • Export of results
  • REVEAL runs on a PC environment


The industry has moved to integrate different software products – OpenServer provides this openness for Petex products.  Petroleum Experts has lead this direction towards openness within the industry such that an operator should be easily able to link various reservoir models, a surface model, the process model and economics into one dynamic representation of an oil and gas field.

The OpenServer feature is designed to provide an open architecture for all the Petroleum Experts products and enables the programs to be directly accessed by other third party programs.

Specifically, OpenServer allows other software programs, such as Excel® or programs using Visual Basic, to access Petroleum Experts programs. An external program in an automated procedure can then access any of Petroleum Experts products to: Import or Export Data and run calculations.

 OpenServer is a licensed software product.

As an illustration of where OpenServer can have benefits to a user:

  • This is an ideal way for users to automate repetitive tasks which may require a series of similar data inputs and calculations to be carried out periodically.
  • Workflow Automation
  • If there are prescribed workflows in the organisation which require a set of steps to be carried out using one of the IPM tools, an OpenServer script could be written to carry out these tasks – workflows
  • Probabilistic forecast – link CrystalBall® or @Risk® linked to IPM to generate a probabilistic forecast
  • Batch Runs: Consider a situation where you have set up a prediction calculation in MBAL. However, it would be of interest to check the final recovery for a range of values of the original oil in place. You could create a spreadsheet in Excel that lists all the OOIPs that you want to try. Then write a VBA macro within Excel which:
  • Gets the first OOIP value from the spreadsheet and sets it in the MBAL tank
  • Runs a production prediction
  • Queries the final recovery from the production results and writes into the spreadsheet
  • Repeat for the next OOIP and so on….
  • Custom Reporting
  • Although PETEX products provide a variety of report formats, it is possible that you require a specific layout for your reports. A VBA macro within Excel® can be written to query the required values from a PETEX product and then write these values in the required format to a spreadsheet.
  • Data Import/Export
  • The OpenServer can be used for transferring data between a database and PETEX programs. The client program can use any technique to access the values in the database (e.g. ODBC, DAO, SQL) and then transfer them with OpenServer.