INNOVATIVE TECHNOLOGY APPLICATIONS IMPROVE THE BOTTOM LINE

Based on a workshop sponsored by PTTC’s Rocky Mountain Region on November 12, 1998, in Denver, CO. 

BOTTOM LINE

There are several innovative new techniques available to help operators enhance the monitoring of downhole conditions, model reservoir complexity, lower water disposal costs, and optimize the ultimate recovery of oil and natural gas.

PROBLEM ADDRESSED

Operators increasingly use a broad spectrum of innovative technologies to improve geophysical interpretations, lower water disposal costs, visually monitor downhole conditions, and enhance production strategies. There also are many methods to improve forecasts of reservoir resistivity, incorporate geological modeling, and help operators sequence stratigraphic studies and geostatistical techniques. This is an important part of effective reservoir characterization for identifying infill drilling targets.

KEY WORDS:

Downhole Video, Resistivity Modeling, Freeze/ Thaw Evaporation, Reservoir Characterization

SPEAKERS

Downhole Video Logging:
Michael Mullen, Halliburton Energy Services

Calculating Water Saturation:
Mark Franklin, Rocky Mountain Petrophysics

Resistivity Modeling/ Neural Networks:
Jeff Arbogast, Acutek

Spectral Decomposition:
Greg Partyka, Amoco Production Co.

Wattenberg Field:
Debra K. Higley, US Geological Survey Steven M. Goolsby, Goolsby Brothers & Associates

TECHNOLOGY OVERVIEW

1. Halliburton Services has the capability to record a downhole video (DHV) that can provide clear images of the wellbore to help operators diagnose downhole problems. The 10-ft-long tool, which is rated to 10,000 psi and 225° F, uses color or black and white cameras that can be run through tubing as small as 2-3/ 8 in. DHV services are used mainly in cased-holes for inspection of downhole equipment and characterization of wellbore fluids, especially their entry points into the wellbore. In addition, DHV services can be used for mechanical wellbore inspection, fluid characterization, and open-hole characterization for highangle or horizontal wells.
   
   
2. Underestimating hydrocarbon reserves is commonly caused by inaccurate corrections for true resistivity. Forward modeling and inversion processing can yield accurate measurements. With this technique, initial estimates of bed boundaries and invaded-zone resistivity are made from the shallow log; while initial estimates of true formation resistivity are made from the deep log. These estimates are forward modeled to generate a simulated log response. Based on comparison to the measured response, the model is adjusted until calculated tool responses closely match.
   
   Recent advances have made resistivity-inversion modeling possible on a PC, with processing speeds more than 100 times faster than previously available. This technique was used to accurately predict hydrocarbon reserves in the Denver-Julesberg Basin in Colorado and in the Alberta Basin in Canada.
   
   
3. Spectral decomposition is a powerful technique to help image and map bed thickness and geological discontinuities. By transforming seismic data into the frequency domain with the Discrete Fourier Transform, short-window amplitude spectra are able to delineate bed thickness variability. Similarly, the phase spectra indicate lateral geological discontinuities.
   
   The spectral decomposition model uses a phase-independent amplitude spectrum, allowing the interpreter to effectively quantify thin-bed interference and detect subtle discontinuities within large 3-D surveys. In a case study from the Red Fork Sandstone of Oklahoma, spectral decomposition and coherency algorithms were the best tools for imaging and mapping an incised valley system.
   
   
4. The economic treatment and disposal of produced water by freeze-thaw technology is possible for lower salinity brines in climates that have seasonal freezing. The technique uses the natural processes of freezecrystallization and evaporation.
   
   During a field test in the San Juan Basin, New Mexico, in the winter of 1997-98, there were 8,000 barrels of produced water, with total dissolved solids (TDS) of 12,000 mg/ l, processed. This resulted in an 80% reduction in the volume of water requiring disposal. Only 1,612 barrels of the original produced water, with a final TDS of 44,900 mg/ l, remained at the end of the evaluation period. These positive results led to additional testing in Colorado’s San Juan Basin and in Wyoming’s Green River Basin.
   
   
5. In reservoir characterization studies, increased visualization of the subsurface improves interpretations. In a test of 3-D imaging in the Terry Sandstone of the Denver Basin, data from more than 1,100 wells were input into a geospatial modeling system. The 3-D model constructed 55 fault surfaces and stratigraphic data were added, resulting in a compartmentalized 3-D reservoir model. Drilling strategies to optimize recovery from multiple fault blocks with a single (horizontal) well were easily developed and evaluated.
   
   An overall low overall recovery— 10.1% of original oil in place— in the North Robertson Unit, west Texas, was attributed to the discontinuous, heterogeneous nature of reservoir zones. Reservoir characterization techniques, such as the construction of a critical new geological model, were used to identify optimal sites for 10-acre infill wells. Results from 14 new producing wells and four injection wells were impressive, confirming the value of targeted infill development in complex reservoirs.
   
   
6. A case study from a South American Middle Eocene reservoir showed that integrating sequence stratigraphic principles can improve the representation of reservoir geology and fluid flow models. To preserve the essential components of the system’s tracks and the bounding surfaces that constitute each sequence, the various facies were simulated using different algorithms to best model specific settings. Multiple realizations were created and upscaled for fluid flow studies, and the results were very encouraging.

CONNECTIONS:

Robert Shumaker,
Department of Geology and Geography West Virginia University,
P. O. Box 6300 Morgantown, WV 26506
Phone: 304-293-5603x4307, Fax 304-293-6522 E-mail rshumake@wvu.edu

Michael Mullen, Halliburton Energy Services
410-17th Street, Suite 900 Denver, CO 80202
Phone 303-899-4700, Fax 303-573-7856

Mark Franklin, Rocky Mountain Petrophysics
18190 E. LaSalle Pl., Aurora, CO 80013
Phone 303-752-3240, E-mail mhfranklin@rmpetr.com

Jeff Arbogast, Acutek, Denver, CO

Greg Partyka, Amoco Production Co.

Debra K. Higley, US Geological Survey
PO Box 25046 Denver Federal Center, MS 939
Denver, CO 80225
Phone 303-236-5791

Steven M. Goolsby, Goolsby Brothers & Associates, Inc.
Denver, CO
e-mail sgoolsby@csn.com

J. A. Harju, Technology Manager, Soil & H ₂ 0 Quality Environmental Business Unit
Gas Research Institute, 8600 W. Bryn Mawr Ave.,
Chicago, IL 60631-3562
Phone 773-399-8198,Fax 773-399-8170, e-mail jharju@gri.org

Jeffrey Yarus
Advanced Reservoir Characterization Specialist
Smedvig Technologies 2985 Briarpark Dr., Suite 1000
Houston, TX 77042
Phone 713-339-2626, Fax 713-339-2627, E-mail jeffy@houston.smedtech.com

For information on PTTC’s Rocky Mountain Region and its activities contact:
Roger Slatt, Department Head, Geology/ Geological Engineering
Colorado School of Mines, Golden CO, 80401-1887
Phone  303-273-3822, Fax 303-273-3859, E-mail rslatt@mines.edu

Disclaimer: No specific application of products or services is endorsed by PTTC. Reasonable steps are taken to ensure the reliability of sources for information that PTTC disseminates; individuals and institutions are solely responsible for the consequences of its use.

The not-for-profit Petroleum Technology Transfer Council is funded primarily by the US Department of Energy’s Office of Fossil Energy, with additional funding from universities, state geological surveys, several state governments, and industry donations.

Petroleum Technology Transfer Council, 2916 West T. C. Jester, Suite 103, Houston, TX 77018
Toll-free 1-888-THE-PTTC; Fax 713-688-0935; E-mail hq@pttc.org; web www.pttc.org