Multi-Component Seismic Analysis and Calibration to Improve Recovery from Algal Mounds: Applications to the Roadrunner/Towaoc Area of the Paradox Basin, Ute Mountain Ute Reservation, Colorado. Goals:
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Multi-Component Seismic Analysis and Calibration to Improve Recovery from Algal Mounds: Applications to the Roadrunner/Towaoc Area of the Paradox Basin, Ute Mountain Ute Reservation, Colorado
The Paradox Basin extends from Utah into Colorado. One exploration target with significant discoveries still possible is the Ismay Algal Mound Play.
The potential exists because these mounds may have little structural expression, and complex reservoir heterogeneity making accurate siting of wells critical to success.
Algal Mound (Salar d’Uyuni, Bolivia)
Muleshoe bioherm, a 60 m high reef mound of Late Mississippian age exposed along the western escarpment of the Scaremento Mountains, New Mexico.
Algal Mounds can have a substantial amount of internal reservoir heterogeneity
“After analysis on Warren Sapp playing offense for the Buccs, I liken it to a 3-D seismic data with several types of seismic attributes revealing geologic factors that control the location of productive algal mound reservoirs in the Paradox Basin.” (anonymous posting on sports website http://www.baseballology.com/warrzone/article.php3?ArticleID=788)
Legacy Energy (Claudia Rebne)
Technical Manager - Seismic
Red Willow (Steve Dobbs)
Technical Manager - Geology
Colorado School of Mines (Tom Davis) – Seismic Acquisition & Interpretation Review
Solid State – (Trent Middleton) 3D Seismic Acquisition
Schlumberger (Richard Pearcy ) – 3C VSP Acquisition
WesternGeco (Rich Van Doak) – “Conventional” 3D Seismic Processing
Axis Geophysics (Bob Parney) – AVO 3D Seismic Processing
Eby Petrograhpic (Dave Eby) – Core Studies
PROJECT MANAGEMENT ORGANIZATION & RESPONSIBILITIES
U. S. Dept. of Energy (Virginia Weyland) Contract Manager
Golder Associates Inc. (Paul La Pointe) Project Management
Ute Mountain Ute Tribe - Resource and Land Owners
Upper and Lower Ismay carbonates produce oil and gas from porous algal mounds at drill depths of about 6000’. Anhydrites provide a top and lateral seal. The mounds generally trend northwest to southeast and are typically 1 to 2 miles long and ¼ to ½ mile wide. Typical field sizes are 1 to 5 MMBOE with average per well reserves of about 300,000 BOE. Some wells have produced over 1 million BOE.
Upper Ismay carbonate mounds are generally 50 to 100’ thick, while Lower Ismay mounds are 40-70’ thick. Mounds are surrounded and overlain by Upper Ismay massive anhydrite that thins abruptly over the tops of the mounds. Lateral stratigraphic changes from porous algal mound facies to off-mound anhydrite facies are abrupt. The key factor associated with the exploration of Ismay algal mounds is predicting these stratigraphic changes. Secondary exploration risk factors include predicting porosity, permeability and fluid content of mounds.
Development of a detailed lithologic model over a known reservoir is a critical technical issue in calibrating the seismic data for reservoir development and future exploration. A detail core study of the Road Runner and Towaoc fields is included in the proposed work to resolve this issue.
This improved drilling success (~50% success) as it did a much better job in delineating lateral stratigraphic changes from off-mound anhydrite to porous carbonate mound.
OVERVIEW OF PREVIOUS USE OF SEISMIC IN ALGAL MOUND EXPLORATION IN THE PARADOX BASIN
Conventional 2D Seismic was used in Early 1980’s for Exploration.
This improved drilling success, but many dry holes were still drilled because of Fresnel zone and out-of-plane migration problems
The 1984 discovery of Kiva field was the result of a geologic model that was confirmed by conventional 2D seismic data. The seismic data was carefully processed and took into consideration the cyclic nature of the geology in the Paradox Formation.
After the confirmation well flowed 1,050 BOPD + 750 Mcfgpd from the Upper Ismay, Meridian Oil and BWAB proceeded in January 1985 to acquire a 3D seismic survey over the possible extent of the new field. The results of that survey show that the 3D images the porous part of the algal mound and demonstrates mound morphology. The survey also demonstrates that the conventional 2D strike line images the crest of the mound from out of the plane of the section (sideswipe), and the 3D migration of the data volume is able to place the image of the mound into its proper position.
The porous mounds are encased in thick massive anhydrite which thins or disappears over the tops of the mounds. This lithology change produces seismic amplitude dims and isochron thicks. The 2D seismic data from the 1980s are used to identify prospects, and new 3D seismic surveys provide for accurate imaging of the thickest and most prolific parts of the algal mounds.
The Horse Canyon Federal # I - I 0 well was drilled just south of the Blanding Prospect Area by Miller Energy in 1998. This well location was based on 3D seismic data, and is only 700 feet away from a dry hole drilled in the 1980s based on 2D seismic data. The well IP'd for 960 BOPD and 3 MMCFGPD. This is a good case history illustrating that the older 2D seismic data did reliably detect a mound, but the 3D seismic data was required to image the productive portion of the mound and resulted in a prolific new discovery.
2D Seismic good for finding mound complexes, but bad for describing geometry of mound and lateral facies variations
Conventional 3D good for describing external mound geometry, and better at describing facies variations and reservoir quality, but still imperfect for reservoir properties and internal geometry
The key to developing a better image of the reservoir’s internal geometry and flow properties is to utilize fluid saturations and azimuthal processing that can directly respond to oriented heterogeneities and changes in fluid saturations.
Thus, acquisition of shear-wave data and advanced azimuthal processing or both shear- and compressional-wave data will potentially provide a much higher resolution of internal mound geometry and, from a reservoir engineering standpoint, a better model of the distribution of reservoir porosity and permeability.
Core and Well Data
10 cores in either the Upper or Lower Ismay in the immediate area. Including relevant core from the surrounding area a total of 500 feet of core.
34 wells: 3wells with well histories and conventional logs. 19 of the 34 wells are producing wells and have production data
Detailed tops database and subsurface mapping (Red Willow)
Existing Seismic Data
600 miles of conventional 2-D data already acquired. 100 miles of which are currently being reprocessed by Red Willow.
Seismic data to be acquired during study
6 square miles of three-dimensional, three-component data.
1 full waveform VSP to calibrate to the S-wave seismic data.
Task 1.1: Core and log data gathering
Assemble data base, gather electronic and paper well data, schedule access to cores
Task 1.2: Seismic Acquisition
Acquire three dimensional three-component seismic data
3D3C seismic data field tapes.
Task 1.3: VSP Acquisition
Acquire three component Vertical Seismic Profile
Three component VSP.
Task 1.4: Seismic Processing
Process all seismic data including conventional P-wave, anisotropic P-wave, azimuthal AVO, and S-wave processing
(1)Conventional P-wave data volume.
(2)Anisotropic velocity P-wave data volume.
(3)Azimuthal AVO data volume
Task 2.1: Core study
Map on and off reservoir lithology by using cores, thin sections and conventional logs.
Lithologic model and map.
Task 2.2: Conventional Seismic interpretation
Interpret the conventional (Three dimensional P-wave) data volume in order to calibrate seismic data to lithology.
P-wave time thickness and attribute mapping.
Task 2.3: S-wave and attribute seismic interpretation
Interpret the 3 seismic data volumes in order to calibrate seismic data to lithology.
(1) S-wave time thickness and attribute mapping.
(2)Anisotropic velocity map.
(3)Azimuthal AVO mapping.
Task 2.4: Engineering data interpretation
Examine production data and well tests to correlate reservoir performance to lithology.
Production index (PI) map of reservoir and inferred permeability.
Task 3.1: Lithologic/geologic structure modeling
Build model for seismic modeling based on core study (Task 2.1)
3-D computer model of lithology based on core analysis.
Task 3.2: Stress field model
Develop map of 3-D stress field based on velocity anisotropy (Task 2.3)
3-D computer model of stress based on anisotropic velocity analysis.
Task 3.3: Seismic simulation
Determine link between seismic response and both lithology and stress by modeling the seismic response interpreted in Tasks 2.2 and 2.3 and determine if there is a link between the seismic data and the lithology and stress (Tasks 3.1 and 3.2)
3-D computer model of seismic response based on lithology, conventional seismic interpretation, attribute mapping and results of stress field mapping.
Task 3.4: Flow simulation
Demonstrate link between seismic response and reservoir response (i.e. permeability, porosity etc.) by simulating flow through geologic model developed in tasks 3.1, 3.2, and 3.3 and the engineering data interpreted in task 2.3
3-D reservoir simulation incorporating all previous mapping and modeling tasks to show extent to which seismic data can predict internal mound architecture.
Task 4.1 Workshops for tribes
Workshops for tribes and all relevant parties
(2)Mid-project progress workshop
(3)Project wrap up workshop
Task 4.2 Website
Website containing project info, technical transfer of findings, status reports and project learnings
Task 4.3 Reporting
Progress and final reports for the DOE and tribes
(1)Three bi-annual reports
(2)One final report
Task 4.4 Briefing for Core
Presentation of status and results for DOE in Tulsa
Presentation for Core as required by solicitation
Task 4.5 Journal articles and public presentations
Publication of one paper in a peer-reviewed journal, and presentation of results and a technical conference
(1)Published technical paper
(303) 318-7798 (fax)
(303) 475-5292 cell
(801) 457-7765 (fax)
Rich Van Dok
CSM Reservoir Characterization Group
Red Willow Production Company
(970) 563-0140 or (970) 563-0145
(970) 563-3681 (fax)
(970) 759-1340 (cell)
(303) 738-9697 or 778-7173
(303) 730-3698 (fax)
Golder Associates Inc.
Paul La Pointe
(425) 882-5498 (fax)
(403) 255-4697 (fax)