GOLDEN, Colo.—Up-to-date results from U.S. and international studies of unconventional resources were presented during a recent meeting at the Colorado School Mines for its Reservoir Characterization Project (RCP). The project is funded by industry to advance geophysical research to explore new methods and technologies to improve reservoir performance, analysis and optimization for a variety of geological settings.
Vaca Muerta Shale Project
The Vaca Muerta project began in 2013 as early-stage research into an unconventional prospect, which is in Argentina’s Neuquen Basin. According to Christian Hanitzsch of Wintershall, “one of the goals of this RCP study is to de-risk the prospect and learn about the good areas and the bad areas. The project is currently in between the pilot phase and the development phase.”
A multi-component seismic survey was conducted in 2016-2017 over the northern area of the current 3-D survey. The current work uses this new 3-C seismic survey along with the 3-C vertical seismic profiling (VSP) to determine the value of using multi-component data. It will characterize anisotropy to improve the understanding of natural fractures, hydraulic fracture development, and propose new drilling and landing locations.
Student Carlos Convers showed results from his thesis on sweet-spot characterization for Vaca Muerta, which is part of the Late Jurassic and Early Cretaceous Mendoza group. For his study, he sought to integrate the total organic content (TOC) and carbonate content with geomechanical properties to discriminate brittle rock and hydrocarbon presence.
“The high TOC areas had low carbonate, which we found in the Upper Vaca Muerta, was in the northeast and southeast in the study area. After we determined a good relationship with elastic parameters and rock properties, we performed a pre-stack inversion that matched up with density to predict which zones have good presence of hydrocarbons with wells logs in the area, which we found in Upper as well as the Middle Vaca Muerta,” he said.
Unified Geosystems' Tagir Galikeev discussed findings from the multi-component dataset with converted wave data to improve the signal-to-noise ratio. “We used a wide-azimuth acquisition with a lone offset in order to make the data more reliable.”
Cabin Creek Field Project
Cabin Creek Field is in the southwestern flank of the Williston Basin. An upcoming project by Denbury Onshore plans to use CO₂ tertiary injection to get production from the carbonate-based Red River formation. The RCP project will help understand the geologic complexity of the target reservoir, predict controls on CO₂ or water flooding, and determine the efficacy of time-lapse multicomponent seismic.
Speaker Paul El Khoury said that the field was discovered by Shell Oil in 1953. After IP using water flooding, Shell conducted a seismic survey and this RCP team is using that data.
A 2015 study noted by El Khoury indicated that the estimated oil-in-place is about 100 billion barrels of oil, and the estimated extraction with primary and secondary recovery is roughly one-third of that.
“Through our model, we can help the operator decide on the ultimate locations for flooding and injectors and help decide the use of horizontal or vertical drilling maximize production. To do this we need to understand the geologic controls for the CO₂ flood. We need to convert the seismic amplitudes into something more meaningful than just porosity.”
Pouce Coupe Field, Canada
The Pouce Coupe Project focuses on the characterization of Montney in western Alberta. The project began in 2009 and previously focused on reservoir characterization using time-lapse multicomponent seismic, downhole microseismic, and geomechanical evaluation. Currently, the downhole microseismic data is being reprocessed to improve the understanding of the induced and stimulated natural fractures. The wells used in the survey were Montney C and D completions.
Speakers Isabel White and Matthew Bray presented initial reprocessing of a microseismic data set. From the dataset, the project goals were to improve reservoir rock estimates and develop new tools and a speed up microseismic processing workflow.
Using inversions, said Bray, “We could identify reservoir rock affected by fracturing with the Montney reservoir. We also want to improve source location and velocity model uncertainty with orthorhombic tomography and quantify geomechnical property changes due to stimulation.”
“We also want to use this to decrease modeling and processing time.”
The study by Noor Wibowo was to map natural fractures and geomechanical properties and deep Jurassic Najmah formation, which was discovered in northern Kuwait in 2006 with production from 14,000 ft to 16,000 ft.
“The Najmah is considered the hydrocarbon source for most of Sabriyah eld reservoirs. The objective of this research is to characterize the Najmah to provide a better understanding of the formation, pore structure, permeability and porosity for future drilling plans.”
Wibowo’s study area is the Najmah 1, 2, and 3, which is fractured carbonate with tight and low porosity with an average thickness of about 55 feet (in their study area).
He is using 3-D seismic data with vertical seismic profiles and rock physic modeling to characterize the reservoir.
Larry Prado can be reached at email@example.com.