May 3, 2006 Meeting - A Day Long Course titled:

"Material Balance & Modeling: Reservoir Engineering Tools Past, Present & Future"

"Reserve Analysis for Unconventional Gas Reservoirs” by Mr. Stuart Cox, Marathon Oil Company

Production from unconventional gas reserves has become an important supply source for the United States gas market. Conventional gas production is declining while demand in increasing this deficit is currently being filled through unconventional gas development. Nine of the top twelve US producing gas field are classified as unconventional.

One of the modules, RMSflowsim is a fully integrated black oil simulator within the reservoir simulation solutions portfolio. It offers accurate modeling of the flow of compressible fluids in the reservoir as well as an extensive range of well and group controls reflecting real world development scenarios. It is unique in the Industry as being the only simulator that is embedded within the 3D reservoir characterization software, and shares input and output with the geological model. The Tempest reservoir simulator provides a modern integrated solution for full field reservoir simulation. At its heart is the MORE engine which runs fully implicit studies and supports a wide range of advanced options.

Unconventional gas reservoirs present unique challenges to the practicing reservoir engineer. One significant challenge is estimating ultimate recoverable reserves for these developments. The extended time required to establish boundary dominated flow in low permeability reservoirs conflicts with the need to accurately estimate recoverable reserves early in the life of the well. This talk focused on performance based reserve estimation techniques for both single layer and non-communicating multi-layer reservoirs. It  presented a critical review and explanation of common techniques used to estimate reserves. Appropriate application and pitfalls of the techniques were discussed. Discussion topics were supplemented with simulation work and field examples. Field exampleswere presented comparing the results of each technique through time for single and multi-layered reservoirs.

The talk demonstrated the importance of early integration of static geologic description and the well performance for the acceleration of reserve bookings and performance evaluation.

Click here to view a pdf file of the slideshow for this talk.

"Evaluation of Condensate Banking in the Near-Borehole Area in Gas Reservoirs” by Dr Bill McCain, Texas A&M University

When the producing bottomhole pressure in a gas condensate well decreases below the dew point pressure of the reservoir gas, a ‘cylinder’ of reservoir around the wellbore develops a high saturation of condensate. The saturation of condensate in this cylinder of reservoir will be much higher than the volume of condensate measured in a constant volume depletion experiment. This causes a severe reduction in gas production rate. The level of condensate saturation depends on rock properties (effective permeability to condensate) and fluid properties (richness of the gas). This presentation discussed the mechanics of the buildup of this cylinder of condensate and examined the dynamics of the condensate saturation as various changes in flow rate and reservoir pressure occur. Simulation models were presented showing several ‘real case’ scenarios.

Click here to view a pdf file of the slideshow for this talk.

“Variations in Modeling with PVT Correlations and Effects on Reservoir Performance Estimates” by Mr. Rob Sutton, Marathon Oil Company.

At the PTTC/PENCOR symposium of 2004, Dave Bergman presented a discussion of oil viscosity correlations, their accuracy and pitfalls if an unsuitable method is selected to represent a given crude oil. Ideally PVT properties are known; however, in situations where PVT is an unknown, correlations can utilized. The talk for 2005 has been expanded to discuss PVT methods for the calculation of the major oil properties of interest for engineers. In particular, these properties include bubble-point pressure, oil formation volume factor, isothermal compressibility, and viscosity. A number of correlations have been published over the years for these key properties and the range of answers derived from these methods can be quite variable. A conceptual black oil reservoir model was created to test these methods and access the impact of this variability on original oil in place, reservoir performance, oil recovery and project life. Oil properties over the range of 20-40 API and gas-oil ratios of 250-750 scf/STB at a reservoir temperature range of 125-250 °F were evaluated.

The talk provided an overview of oil PVT correlations and their variability. Results from the simulation studies will be presented to quantify the impact of correlation selection on reservoir performance and recovery.

Click here to view a pdf file of the slideshow for this talk.

“A Look at Equation of State Modeling Applications and Various Case Histories” by Toddy Guidry, PENCOR Division of Core Laboratories

This “applications” presentation showed several real life cases where EOS models can provide very valuable data. In the absence of samples, information or because of economics, it is sometimes not possible to obtain important fluid/flow assurance/PVT properties that may aid in decisions. EOS modeling is an effective alternative and may provide data that is otherwise not available. Cases histories with real data such as multi-scenario separator tests, optimum separator pressure determination, correcting PVT properties for oil-based drilling mud contamination, phase behavior experiments and obtaining PVT data on reservoirs where samples are not available were presented. This was not a “how to tune” or “best software package” presentation, but rather provided situations where EOS modeling can provide useful information in the absence of measured data, especially in cases where some production data exists or related fluid data exists. EOS modeling can carry the accuracy a step further than correlations presented earlier when some amount of information is known.

Click here to view a pdf file of the slideshow for this talk.

November 30, 2005 Meeting

Mr. Raj Damodaran, Senior Reservoir Geoscientist with Roxar, Inc. in Houston, gave a presentation on Roxar’s Irap-RMS and Tempest simulation packages.

The Irap RMS portfolio consists of eleven interrelated modules that share a common user interface, data model and visualization environment. The unified data model helps users to integrate data at different scales through visual and numerical feedback. Each module delivers a focused set of technical tools appropriate to a particular stage of the workflow. The Irap-RMS portfolio consists of eleven interrelated modules that share a common user interface, data model and visualization environment. The unified data model helps users to integrate data at different scales through visual and numerical feedback. Each module delivers a focused set of technical tools appropriate to a particular stage of the workflow.

One of the modules, RMSflowsim is a fully integrated black oil simulator within the reservoir simulation solutions portfolio. It offers accurate modeling of the flow of compressible fluids in the reservoir as well as an extensive range of well and group controls reflecting real world development scenarios. It is unique in the Industry as being the only simulator that is embedded within the 3D reservoir characterization software, and shares input and output with the geological model. The Tempest reservoir simulator provides a modern integrated solution for full field reservoir simulation. At its heart is the MORE engine which runs fully implicit studies and supports a wide range of advanced options.

More information on Irap-RMS and Tempest can be obtained by visiting the website www.roxar.com.

October 27, 2005 Meeting

Mr. Aaron Cheng of Seismic Micro-Technology (SMT) presented SURE, a state-of-the-art reservoir simulator utilizing the powerful unstructured PEBITM grid technology.

SURE is easy to use and is highly cost-effective. With PEBITM grids, the user can accurately model both simple and complex reservoir structures and faults, and can handle reservoirs on multiple scales. Such robust modeling is crucial for accurate determination of oil and gas reserves and prediction of production performance. With SURE and PEBITM gridding, these results can be obtained in shorter simulation runs relative to computations using conventional gridding technology. SMT will discuss the 5 main modules of SURE: SUREGrid, SURESim, SUREPlot, SUREPVT and SUREFrac. These modules are highly intuitive and GUI driven, and reservoir and well data can be quickly inputted and edited. In particular, SMT will demonstrate how SUREGrid and SURESim can be used to rapidly build and run simulation models to obtain results, and thus allow users to reduce risk and more effectively manage reservoirs. SMT offers a free, 30-day trial of SURE. More information on SURE can be obtained by visiting the website www.seismicmicro.com.

April 27, 2005 Meeting

Mr. Ralph Nelms of Kerr McGee presented a demonstration of the New Mexico Tech production history matching and decline type curve forecasting program TIGPA2000.

TIGPA2000 was created by Mr. Juan Munoz, Mr. Her-Yuan Chen, and Mr. Lawrence Teufel from New Mexico Tech and is discussed in SPE paper 71067 published in May 2001. TIGPA2000 is an Excel program containing modified Fetckovich type curves for tight gas sand reservoirs with the ability to evaluate linear reservoir drainage patterns. Mr. Nelms modified the Excel program to automatically calculate the linear volumetric drainage area size and dimensions not contained in the original software. Results from the TIGPA2000 type curve program were compared with both the RPI and the Fekete RTA type curve programs for tight gas sand fractured reservoirs to determine drainage areas and EUR forecasts. Examples from both the Moxa Arch Frontier formation and Pinedale Anticline Lance/Mesaverde formations were presented. The password to access both the Visual Basic program code lines, and the spreadsheets, was provided so users could modify and customize the TIGPA2000 type curve program for different applications. The software is free and can be downloaded from the GO-TECH web site at http://octane.nmt.edu. When downloading from the software icon, be sure and right click on the word software and then select “Open”.

Copies of files from  the presentation:
Blue Rim State 1 Production
BLUE RIM STATE 1 FINAL nmt
Champlain 288 D1 nmt
PTTC Reservoir Simulation Users Group 4 27

March 17, 2005 Meeting

Mr. Scott Reeves of ARI presented “Probabilistic Modeling Using a New Boast98 Module.” Free software was distributed, see description below.

In late 2004 the US DOE awarded an R&D project to Advanced Resources International (ARI) of Houston, Texas to develop a Visual Basic, MS Windows compatible computer interface program that integrates DOE’s free BOAST 98 simulator with Monte-Carlo simulation software. The new application has the capability to establish probability distributions around most BOAST 98 input parameters, including coefficients for automatically generating three-phase relative permeability curves, and then automatically running thousands of simulation cases. Results are compiled in an MS Access database and output probability distributions of any number of parameters e.g., hydrocarbon recoveries) can be generated. Tornado plots can also be created to identify those input parameters with the greatest influence on the target output parameters. Finally, if historical data is available, goodness of fit calculations can be made between actual and simulated data, for any number of parameters simultaneously, to assist in the history-matching process.

This new model was presented and demonstrated at the meeting.  Up to ten free copies of the application were provided to interested companies to beta-test and provide feedback on it over a three-month period. A final product release will be made shortly thereafter.

View a copy of the presentation in pdf format.

February 23, 2005 Meeting

Jim Mack, President and CEO of TIORCO, Inc. presented “What One Needs to Know to Simulate a Polymer Flood or In-Depth Polymer Crosslink Gel Process.”

January 24, 2005 Meeting

Brian Rothkopf (a long-time supporter of our group), Forest Oil, presented “Case Study: Merging Modern Reservoir Characterization with Traditional Reservoir Engineering.”

The presentation described a Williston Basin field example where traditional reservoir engineering techniques from 40 years of waterflooding history were integrated into the modern reservoir characterization-simulation workflow.

November 18, 2004 Meeting

Mr. Jim Flynn, Manager of Simulation Business Development with Schlumberger in Houston, gave a presentation on the value of reservoir simulation for coal bed methane operations.

Mr. Flynn described how the ECLIPSE Coal Bed Methane Template can help operators evaluate the benefits of multi-well interference and understand the effects of production operations on overall coal methane field performance. The ECLIPSE CBM Template model is an easy to use interface to compare the benefits of vertical, horizontal, multi-branch, and hydraulically fractured completion designs.   The template model enables the power of ECLIPSE with no simulation experience required. Information on the software can be accessed at: http://www.sis.slb.com/content/software/simulation/eclipse_options/cbm.asp?.

October 19, 2004 Meeting

Mr. Dave Anderson of Fekete presented RKA, their pressure transient program.  Those in attendance received a free 21 day trial of the software including the CBM simulation program.

September 22, 2004 Meeting

Mr. Scott R. Reeves, Executive Vice President, Advanced Resources International, Inc., Houston, presented CBM, ECBM, and gas shale modeling using the COMET3 simulator.

COMET3 is an advanced reservoir simulator for modeling primary recovery, enhanced recovery and carbon sequestration for coalbed methane and gas shale reservoirs. The presentation covered the basic premises of coalbed methane simulation, plus some of the more advanced concepts such as triple-porosity/dual-permeability modeling, coal matrix shrinkage/swelling, and enhanced recovery. The application of computer-assisted history matching and probabilistic forecasting for CBM and gas shale reservoirs will also be presented. A demonstration of the software will be made, and example input datasets provided for a variety of cases. The model is available for monthly rental via the web thru the Petris Technology ASP portal.
Click here for a pdf of the presentation.

May 26, 2004 MEETING

Dr. James C. Ertl with the Computer Modeling Group (CMG) give a presentation on GEM, a CO₂ and CBM simulator.

GEM is CMG's general equation-of-state (EOS) based compositional reservoir simulator for modeling the flow of three-phase, multi-component fluids. GEM is a robust, fully compositional simulator used to model any type of reservoir. GEM provides extensive well management options, plus a flexible set of surface separator facilities, including EOS and gas plant separator stages, enabling the modeling of flow from the sand face to the outlets of the separator trains.

GEM simulates a variety of structurally complex and varying fluid combinations beyond the conventional black oil simulators as well as K-value compositional simulators. GEM will effectively model:

• Gas condensate recovery
  
• Volatile oil reservoirs
  
• CO2 and hydrocarbon injection
  
• Gas cycling and re-cycling
  
• WAG processes
  
• CBM
  

April 28, 2004 Work Session

Mr. James R. Gilman, Director of Engineering at iReservoir.com presented a talk on streamline-based reservoir simulation.

Streamline-based reservoir simulation can be an effective and complimentary technology to more traditional methods such as finite differences. These methods can be effective in solving large, geologically complex system where displacement (e.g. water flooding or miscible displacement) is the primary recovery mechanism. This talk will 1) summarize some of the key principles of streamline techniques including their advantages and disadvantages, 2) discuss appropriate applications, and 3) illustrate some of the novel information available from streamline methods (e.g. well allocation factors, swept volumes, and visualization of flow patterns).

The three major Streamline-based simulation programs commercially available are (1) StreamSim’s 3DSL program, (2) Schlumberger’s FrontSim program and (3) Roxar’s RMSstream program. StreamSim has a web site with information and articles that can be downloaded at http://www.streamsim.com. The StreamSim model was developed at Stanford University and is known as 3DSL. The Schlumberger Streamline-based model is known at FrontSim and is a stand-alone program from the popular Eclipse conventional grid cell finite element simulation program. Information of the Schlumberger/Geoquest FrontSim model can be accessed on http://www.sis.slb.com . Roxar’s web site is at http://www.roxar.com and contains information and access to SPE articles on Streamline-based simulation.

Universities which have created Streamline-based simulation programs include Texas A&M, Stanford University, Colorado School of Mines and Imperial College. The Imperial College website http://www.imperial.ac.uk has many SPE articles that can be downloaded free on several topics related to Streamline-based simulation. Mr. Martin J. Blunt, and other researchers at Imperial College, have recently published several articles on improvements in Streamline-based simulation programming taking into account in-compressible fluids and simulation of natural fractures. Mark Thiele of Aramco is doing additional work on Streamline-based modeling of natural fractures as published in SPE 77374.

Streamline-based simulation should be viewed as a complementary tool to conventional simulation programming for waterflood modeling and miscible flood modeling. One strong advantage of Streamline-based simulation is visualization of reservoir changes. This can be a very powerful tool especially for waterflood projects where injector-producer interactions can be seen and changes made in the patterns and injection rates to balance the waterflood. Streamline-based simulation can be used for Tracer modeling, immiscible flooding, miscible flooding and black oil simulation. Solution gas cannot be effectively modeled using Streamline-based programming. Streamline-based simulation is now being used to model the Alaska Prudahoe Bay Field for miscible gas injection.

Streamline-based simulation requires (1) incompressible flow (2) thermodynamic equilibrium (3) no gravity or capillary forces. Wells with high permeability do not work well with Streamline-based simulation. Polymer flooding cannot be simulated with Streamline-based programming. The key advantages to Streamline-based simulation are increased processing speed since water saturations are moved alone streamlines using simpler physic’s numerical solvers vs. individual grid-by grid-solutions used by finite element simulation programs. Material balance smearing can also occur. Streamline-based simulation programs are difficult to modify in the middle of a simulation run whereas conventional grid block finite element programs are much easier to modify as the run is being made.

Streamline-based simulation reconstitutes the conventional finite element grid solutions into a 1D independent solution method. Water saturation is calculated as a function of time of flight along streamlines vs. grid-by-grid solutions. Reducing the 3-D mathematical solutions to a 1D solution is the key to time savings offered by Streamline-based simulation programming. Each grid cell must have a lease one streamline present. Multiple streamlines may exist through each single grid cell.

Major advantages of Streamline-based simulation include:

Order of magnitude faster

Large systems can be solved quickly

Can use in parallel with conventional models

Less numerical smearing

Path visualization including time of flight information of water saturation and pressure changes.

March 24, 2004 Work Session

Mr. Alejandro Albertoni, NITEC LLC, presented: A Consistent Methodology for Utilizing History Match "Miss-Matches" to Adjust the Reservoir Description in Reservoir Simulation Models. History matching of petroleum reservoir simulation models is a time consuming, data intensive process, but one that must be done and done well to have a useful model for predicting future performance. NITEC has found through many large integrated reservoir studies that a consistent methodology for adjusting reservoir parameters must be followed to assure reliable results. This approach has been encapsulated in a simulation workflow software tool developed and used by NITEC engineers. Mr. Albertoni showed how this methodology guides the adjustment of the reservoir description and significantly speeds the history matching process. This was demonstrated using the results from a South American tight gas field with over 200 wells. While this may be a larger problem than members of the user group may normally tackle, the methodology is equally valuable for smaller reservoir studies.

February 25, 2004

Free BOAST training for members.

January 29, 2004 Work Session

Mr. Ralph Nelms presented a simulation case study for a 5th, or 6th, well infill drilling program in the Frontier Formation in the Moxa Arch using the IFLO simulation program. The IFLO gas reservoir model simulates 30 years of historical production history, and up to 60 years of total well life, from up to four 160-acre wells drilled in a 640-acre drainage area using a 29 x 29 grid block pattern. Individual grid block values for net pay and porosity were taken from isopach maps and loaded into Excel files. Procedures for transferring Excel grid block reservoir tables into the IFLO input data file will be presented. Modifications to the IFLO model were presented to account for directional permeability and pressure depletion to model the N45E orientation of the natural fractures in Frontier gas reservoirs. Click here to download the presentation including a simulation case demonstrating how changes in well location can either add new reserves or accelerate recovery of existing reserves. The file includes all IFLO input and output files and graphical presentations of drainage patterns. Please note; the kreiging address is 3dfmaps.com, not 3dfmap.com.

December 2003 - No work Session

November 20, 2003 Work Session

Dick Barden, President of Vertex Petroleum Systems demonstrated Vertex 1000. The advantage offered by the Vertex system over conventional grid-based methods is that it gives non-specialists in reservoir simulation methodology - production, exploitation and reservoir engineers - the ability to make accurate productivity calculations quickly, easily and inexpensively. The Vertex model can deliver near full reservoir simulation power to the non-specialist using data, which is both readily accessible and easy to use. The luncheon presentation included a brief discussion of reservoir simulation using the Boundary Element Method and how it differs from conventional grid-based simulators; click here for more information. Brief comparison with Stream Line methods was also made; click here for additional information. Mr. Barden then stepped through several tight gas studies, including model configuration, data input, history matching, response signature interpretation and output analysis, followed by some “what if” scenarios to determine the feasibility of drilling new wells at different locations in each field. The list price of Vertex 1000 is $14,000; the option of working solely with the Vertex consulting group or in combination with your own copy of the software is possible.

For additional information click here to visit the Vertex web site.

October 23, 2003 Work Session

Mr. Walt King demonstrated several simulation models for vertical and horizontal primary wells, water injection into vertical and horizontal wells, Polymer and ASP injection, dual porosity fractured reservoirs, simulation of hydraulically fractures wells and CBM on the Exodus program. Exodus is a very user friendly open architecture system which can use any type of standard, or custom, input data format including Excel, Dwights, etc. Grid refinement was demonstrated on several wells with conventional and 3D graphics presentations. Digitized isopach maps of net pay, water saturation, or porosity from mapping programs such as Surfer can be directly loaded into input files in Exodus. Reservoir characteristics such as permeability can be inputted in table form or calculated from porosity. Data input is accomplished using Windows screen pull downs for grid definition, PVT data, well locations, production history input, etc. Any problems encountered during the simulation process can be easily identified and traced via output sheets or clicking on individual grid blocks. Purchase price for the a base 2000 cell simulation program including CBM, CO2 and Polymer simulation capabilities is about 10% -20% of larger commercial simulation programs. Mr. King made a 30 day free demo of the program available for attendees of the users group. Click here to download the PowerPoint presentation given at the meeting.

For additional information click here to e-mail Mr. King or click here to visit the Exodus web site.

Click here to view Exodus cost information. Click here to view Exodus CBM cost information.

September 17, 2003 Work Session

Mr. Stan Kleinsteiber of Malkewicz Hueni and Associates presented a demonstration of the SWSS (Single Well Simulator) and GAS3D simulator. GAS3D is a finite difference single phase simulation program developed by BP Amoco in-house and now available for lease through Malkewicz Hueni and Associates. GAS3D is a simple to use and fast multiple well simulation program linked to the SWSS program. The SWSS program allows history matching of actual production with simulation forecasts for each single well to be feed into the GAS3D multiple well simulation program for infill drilling potential analysis. Mr. Kleinsteiber demonstrated how the GAS3D simulator can be adapted to simulate 5th well drilling candidates in tight gas sand formations taking into account grid modification for natural fracture orientation.

The 5 spot drilling case that was run demonstrated that one well in a central location would accelerate production, while a drilling location off center would add new reserves. The software is available for lease at $1500 per month, and a free 30 day demo license is available. For more information click here or click here to e-mail Mr. Kleinsteiber.

May 21, 2003 Work Session

Mark Sippel gave a follow-up presentation of his Boast 98 history and primary prediction for the Red River B Zone at North Buffalo Field, Harding County, SD. Results will be compared with output from Petroway's Winboast and Gemini's Merlin for the same problem. Click here for example files distributed at the meeting.

Ralph Nelms also present an IFLO simulation of a North Dakota Red River D gas reservoir that has produced 13 bcf with a full water drive; the simulation shows the water influx over time. Click here for these data files.

March 13, 2003 Work Session

Brian Rothkopf with iReservoir.com, Inc. presented "Case Study: Merging Modern Reservoir Characterization with Traditional Reservoir Engineering" Click here for an abstract and reference to the paper.

February 20, 2003 Work Session

Mr. Carlos Ochoa and Mr. Ralph Nelms of Westport will present the results of vertical and horizontal CO2 injection scenarios using the smaller version of IFLO with a limit of 5000 cells. A more advanced version of IFLO sells for $1500 but the examples given at the meeting were limited to the smaller version that can be purchased for $129 through SPE. The software does not ship with any examples of horizontal wells, much less a horizontal injection well, so this is a unique case. Click here for example files distributed at the meeting.

January 23, 2003 Work Session

Ralph Nelms, Westport Resources, presented a Red River B horizontal well simulation for the Westport Carl Olson #1-13 using Boast VHS. Projected simulation results were compared to actual well performance for the first 60 days of production. Models for a single horizontal well based upon history matching of offset vertical wells plus cases for three parallel horizontal wells with and without injection into the center horizontal well were presented and provided to the attendees. Click here for a write-up on the study, and example files distributed at the meeting.

November 18, 2002 Work Session

Mark Sippel, Consulting Petroleum Engineer, presented Red River B vertical and horizontal well simulation using EdBoast 98. Click here for example files from this case study.

October 22, 2002 Work Session

Dr. John Fanchi, Colorado School of Mines, presented Integrated Flow Modeling. He is author of Integrated Flow Modeling, a combination of text and software (Elsevier, 2000, 304 pp., available from SPE for $134.00/$120.50 members.) It provides geoscientists and engineers with both theoretical concepts and practical skills. His presentation also included a demonstration of the integrated flow simulator (IFLO) software for oil and gas and coalbed methane applications. For more information, click here to visit Dr. Fanchi's website.

September 17, 2002 Work Session

Rhonda Gathers of Questa Engineering presented the 3M Coalbed Methane Simulator. This free software as well as an extensive report may be downloaded from the COGCC website by clicking here.

Click here for the example files distributed at the meeting.

June 12, 2002 Work Session

Ralph Nelms of Westport presented a horizontal case study of a Fryburg horizontal well using Boast VHS software. Click here for the example files distributed at the meeting.