Tech Division Events
Geomodeling Division
For more information on this Division, please contact the Division Chair, Weishan Ren, ConocoPhillilps, at (403) 233-3428 or via email at weishan.ren@conocophillips.com.
Division Profile
The mandate of the Geomodeling Division is to provide CSPG members with opportunities for education and information related to technical developments in the subject areas of geomathematics and computer technologies as they are used in the pursuit of petroleum exploration and development. As a main contribution of the division, technical luncheon presentations are held once a month, usually on the last Wednesday of the month.
The subjects that are presented in these technical talks include, for example, The latest developments in geomathematical applications, Geological modeling technology, Geostatistical approaches to modeling and risk analysis, Geological case studies using computer technology and the benefits, Digital data organization - storage and retrieval. In addition, ad hoc forums may be organized where members can discuss geomathematical and geological computer issues with experts in the field.The Geomodeling Division does not endorse or promote the use of specific commercial software products, nor does it perform any testing or comparative studies of such products.We do encourage volunteers to present public talks on case histories that illustrate the use of technology and methods.
The success of the Division depends on volunteer participation. CSPG members are encouraged to attend the activities of the Geomodeling Division and to be involved in organizing these activities. Division meetings are held once a month over lunch. If you are interested in joining this committee or if you have suggestions for luncheon talks or other activities, please contact any members of the committee.
Weishan Ren, Chairperson, (403) 233-3428, Weishan.Ren@conocophillips.com
Peter
Boyle, (403) 287-3228, Peter_Boyle@shaw.ca
Tom Cox, (403)
716-4497, tcox@calgary.oilfield.slb.com
Robert
Chelak, (403) 290-0551, Robert.Chelak@roxar.com
Ned Etris, (403)
296-5729, netris@petro-canada.ca
David
Garner, (403) 234-5875, DavidGarner@chevron.com
Sean Hayes, s.hayes@zinmac.com
Blair
Mattison, (403) 645-2716, Blair.Mattison@encana.com
David
Middleton, (403) 296-4604, MIDDLETN@petro-canada.ca
Tony Wain, twain@zinmac.com
Division Talks
Enhancing Geologic Resource Modeling of Oil Sands Mining Leases Using Stochastic Modeling
Speaker
Ned Etris, Petro-Canada
12:00 Noon
September 23, 2008
EnCana Amphitheatre
2nd Floor, East end of the Calgary Tower Complex
1st Street and 9th Avenue SE
Calgary, Alberta
Abstract
Traditional oil sands mining operations have used deterministic techniques to create resource models. In situ oil sands operations, however, often use stochastic techniques to create a set of equally realistic geological models, all of which honor drill hole data, to assess the variability of estimates for recoverable bitumen volumes. Both types of bitumen recovery operations can benefit from the advantages of a stochastic modeling process for resource model building and uncertainty evaluation.
To illustrate the benefits for mining, this talk will present a case study representing the first application of stochastic modeling for resource estimation and mine planning in a real oil sands mine: the Fort Hills Oil Sands Project. Fort Hills is currently in the planning stage where the information from stochastic modeling is most beneficial.
Models for mining and models for in situ are used as input to recovery process simulators, and both types of recovery are sensitive to the distribution of rock properties in the subsurface, although in different ways. In general, geological models for mining operations have less uncertainty than models for in situ operations due to the much closer drill hole spacing and the better understood recovery process for oil sands mining, but the level of uncertainty is not zero.
Furthermore, because drill hole spacing is not dense everywhere across the lease at the same time, uncertainty in the sparsely drilled areas and for the lease as a whole is probably just as large as for in situ projects. For these reasons, stochastic modeling is a natural fit for oil sands mining operations.
Reservoir heterogeneity is just as important for mining operations as for in situ, although different aspects of the heterogeneity are important. Resource estimations of in-place bitumen volumes can be equally accurate with deterministic or stochastic techniques, and yet recoverable volumes may be very different after applying recovery process simulation. The difference arises because deterministic techniques sacrifice honoring of heterogeneity in order to provide low local prediction error. Heterogeneity, however, may be a critical factor to the success of the recovery operation.
Therefore, deterministic techniques are more suitable for such tasks as identifying specific locations where the ore grade is highest, or finding the best position for a mine pit edge to include as much ore as possible while excluding as much waste as possible. Conversely, deterministic techniques are less suitable for mine extraction or fluid flow simulation, in which a realistic distribution of rock properties is the most important feature regardless of whether those features are modeled in the correct location.
The case study discussion for this talk covers these general issues as well as outlining the specific stochastic modeling process used for Fort Hills. The modeling process applied provides a reliable estimate of in-place resources, and also quantifies the degree of uncertainty for resource volumes. Mine planning was done using the complete set of 100 realizations for purposes where local accuracy was important, or using a single realization selected by a ranking process for purposes that demanded realistic heterogeneity.
Figure 1: Comparison of map slices through models built using different methods. The nearest neighbor model represents the traditional oil sands modeling method, whereas the simulation model represents the stochastic method used for Fort Hills. Open black circles are drill hole locations.
Figure 2: Comparison of cross sections through models built using different methods. The nearest neighbor model represents the traditional oil sands modeling method, whereas the simulation model represents the stochastic method used for Fort Hills.
Biography
Dr. Ned Etris is a professional geologist with 17 years of petroleum industry experience ranging from research to prospecting, with specialization in reservoir characterization and geomodeling. For the past three years, Dr. Etris has been working for Petro-Canada as the lead geologist in the reservoir characterization group, working on oil sands projects for both in situ development and mining, most notably on the Fort Hills mine project. Dr. Etris is a member of CSPG, AAPG, SPE, and APEGGA.
Ned received his Masters and Doctoral degrees in geology from the University of South Carolina, using quantitative analyses to integrate sedimentology with the petrophysics of core and wireline logs. From 1991 to 1996, Ned worked in exploration & production companies in Calgary, and from 1996 to 2005 he worked in consulting firms, applying geological and petrophysical analyses to develop numerous creative solutions to optimizing production performance and estimating resources and reserves in reservoirs around the world. As a consultant, Ned became involved in studies of unconventional resources, particularly Alberta's oil sands, working for major oil companies in Calgary. In 2007, Ned completed the Citation Program in Applied Geostatistics from the University of Alberta.
Importance of Geological Heterogeneity on Fluid Flow Behavior in a SAGD Process: An Engineering Perspective
Speaker
Farrukh Akram,
Schlumberger Canada Limited
12:00 Noon
October 21, 2008
EnCana Amphitheatre
2nd Floor, East end of the Calgary Tower Complex
1st Street and 9th Avenue SE
Calgary, Alberta
Abstract
Standing at 2.5 trillion barrels, Canada has the largest portion of the world's ultra-heavy oil and bitumen resources. While shallow heavy oil reserves are extracted from pit mines, deeper reserves can only be extracted through wells. Production requires operations such as Steam Assisted Gravity Drainage (SAGD) and Cyclic Steam Simulation (CSS) methods. Optimal well placement defines the propagation of steam within the reservoir and the resulting flow of crude towards the producers. These steam recovery methods require a strong geological reservoir characterization in order to assist with the field development plans. It is important for both the geologists and the engineers to understand the effect of assumptions used in designing the production methodology. This presentation looks at the effect of reservoir characterization on the engineering design through the use of flow simulation for a sample Athabasca Oil Sands area.
When a geological reservoir model becomes an engineering flow simulation model, changes are often introduced to satisfy engineering constraints. Grid cell orientation, facies grouping, and cell size are some of the common changes that occur. Why the reservoir flow simulation requires these changes will be investigated.
A heterogeneous geological reservoir (Figure 1) model was used as our test case. A full field thermal model was developed to simulate the SAGD recovery process. The study examined a typical SAGD pad consisting of six well pairs (Figure 2). Since horizontal SAGD pairs are seldom perfectly horizontal, an advanced well bore model is used to account for the complex flow effects in the slowly flowing horizontal wells.
This presentation demonstrates the effect of the geological model and engineering constraints on the flow simulation and the formation of the steam chamber due to the presence of geological baffles and barriers. The behavior of the SAGD process under a full field, multiple pair environment in a heterogeneous reservoir is observed. These heterogeneities in a full field environment cause irregularities in the steam chamber formation and can result in flow interactions between well pairs, as shown in Figure 3, which traditionally may have been over looked. Sensitivity analysis was done on the grid block size to determine the optimal flow solution accuracy versus the simulation runtime.
Figure 1: A heterogeneous geological model.
Figure 2: SAGD well placement and spacing.
Figure 3: Steam chamber after four years of injection. The presence of shale and low permeability
zones effect theformation and inter-connection between the individual steam chambers.
Biography
Farrukh Akram received a Bachelor's degree in Mechanical Engineering from NED University of Engineering and Technology and a Master's degree in Petroleum Engineering from Dalhousie University. He is a reservoir engineer for Schlumberger Information Solutions specializing in integrated subsurface workflows and geological modeling and reservoir simulation software. He teaches courses in Petrel Reservoir Engineering and develops workflows for oil sands and offshore reservoirs. He has authored two technical papers, co-authored two other papers and co-presented two papers to other organizations on modeling, simulation and field development planning. He is a member of the Society of Petroleum Engineers.
Information
There is no charge. Non-members of the CSPG are also welcome. Please bring your
lunch. For details or to present a talk in the future, please contact Weishan
Ren, ConocoPhillilps, at (403) 233-3428 or via email at weishan.ren@conocophillips.com.
