The next fall meeting of the Simulation Users Group will be a day long course on May 3, 2006, 8:00 am – 4:00 pm at the Denver Athletic Club, 1325 Glenarm Place. (Note that the times are different from the ad. in the Denver SPE Newsletter) The fee of $95 includes lunch. The subject matter will be:

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

Register by going to the events pages of this website. Click Here

Schedule:

8:00am - 9:00am - Registration

9:00am – 10:15am – Mr. Stuart Cox, Marathon Oil Company
“Reserve Analysis for Unconventional Gas Reservoirs”

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.

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 focuses on performance based reserve estimation techniques for both single layer and non-communicating multi-layer reservoirs. It will present a critical review and explanation of common techniques used to estimate reserves. Appropriate application and pitfalls of the techniques will be discussed. Discussion topics will be supplemented with simulation work and field examples. Field examples will be presented comparing the results of each technique through time for single and multi-layered reservoirs.

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

10:30am – 11:45am Dr Bill McCain, Texas A&M University
“Evaluation of Condensate Banking in the Near-Borehole Area in Gas Reservoirs”

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 will discuss the mechanics of the buildup of this cylinder of condensate and examine the dynamics of the condensate saturation as various changes in flow rate and reservoir pressure occur. Simulation models will be presented showing several ‘real case’ scenarios.

11:45am – 1:00pm Lunch (provided)

1:00pm – 2:15pm Mr. Rob Sutton, Marathon Oil Company
“Variations in Modeling with PVT Correlations and Effects on Reservoir Performance Estimates”.

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 provides 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.

2:30pm – 3:30pm Toddy Guidry, PENCOR Division of Core Laboratories
“A Look at Equation of State Modeling Applications and Various Case Histories”

 This “applications” presentation will show 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 will all be presented. This will not be a “how to tune” or “best software package” presentation, but rather will provide 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.

Register by going to the events pages of this website. Click Here

Mark your calendar!

Sandra Mark
PTTC Rocky Mountain Region
smark.95@alum.mines.edu
303.273.3107