EORI Library

Osage Partners, LLC. a Wyoming based operator contacted EORI and requested the institute’s assistance regarding their Muddy/Newcastle assets. The operator provided EORI with core from four wells and associated data related to the Osage field in the Powder River Basin. The operator requested that EORI characterize the clay mineralogy of the pay sands using XRD, SEM, and CEC analysis of samples from the provided core.

• We think of CO2 as the greenhouse gas (GHG) causing global warming.
• The Stern Report and the several IPCC (Intergovernmental Panel on Climate Change) reports are gaining acceptance.
• In its most recent report (AR4 Synthesis Report November 17, 2007) the IPCC has written: Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level.
• The report goes further to say: Most of the observed increase in globallyaveraged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations.
• The Supreme Court on April 2, 2007 in a 5 to 4 decision decided that CO2 was a pollutant and the EPA could regulate auto emissions of the GHG (Chemical & Engineering News, April 3, 2007).

Development and production of coalbed methane involves the production of large volumes of water. The salinities and sodium adsorption ratios of coalbed methane (CBM) water from the Powder River Basin range from 370 to 1,940 ppm and 5.6 to 69 respectively. Surface discharge of CBM water can create serious environmental problems; subsurface injection is generally viewed as economically nonviable. It has been shown that oil recovery from reservoir sandstones can be improved by low salinity waterflooding for salinities ranging up to 5,000 ppm. There may be both technical and regulatory advantages to application of CBM water to oil recovery by waterflooding. Thin section and scanning electron microscope studies of the mineral constituents and distribution of Tensleep and Minnelusa sandstones show they are typically composed of quartz, feldspar, dolomite and anhydrite cements but have very low clay content. The sands contain interstitial dolomite crystals in the size range of up to about 10 microns. Three sandstone cores from the Tensleep formation in Wyoming were tested for tertiary response to injection of CBM water. The cores were first flooded with high salinity Minnelusa formation brine of 38,651 ppm to establish residual oil saturation. Synthetic CBM water of 1,316 ppm was then injected. Tertiary recovery by injection of CBM water ranged from 3 to 9.5% with recoveries for all but one flood being in the range of 5.9 to 9.5%. Previous studies showed that the presence of clay was needed for response to low salinity flooding. As a test of the recovery mechanism, a Tensleep core was preflushed with 15% hydrochloric acid to dissolve the dolomite crystals. The treated core showed no tertiary recovery or pressure response to CBM water.

(SPE 113410, University of Wyoming)

Enhanced-Oil Recovery (EOR) for asset acquisition or rejuvenation involves intertwined decisions. In this sense, EOR operations are tied to a perception of high investments that demand EOR workflows with screening procedures, simulation and detailed economic evaluations. Procedures have been developed over the years to execute EOR evaluation workflows.

This work is motivated by the need for inexpensive carboncapture technology for combustion-based power plants. Such power plants produce electricity by converting coal or natural gas to carbon dioxide (CO2), which is normally vented as an 11%-12% component of flue gas that contains a balance of nitrogen and other minor components. Separating CO2 from such a flue-gas mixture poses no special technical problems for the known absorption, pressure-swing adsorption (PSA), and membrane technologies. However, these technologies have a tendency to be expensive for two principal reasons: the hot flue gas is produced at low pressure and the separated component (CO2) is highly dilute with an inert component (nitrogen).

The simulation evaluation concluded that gravity stable CO2 flooding can be an effective EOR method for the Grieve Muddy reservoir. Up to 23 MMBO could ultimately be recovered by gravity stable CO2 flooding. The reservoir has potential to sequester more than 145 BSCF of CO2 at the end of CO2 flooding operation. Prior to the simulation of history matching and CO2 flooding, a four-layer Petrel model of Grieve Muddy reservoir was developed based on the identified facies in the Muddy channel sand and the overlain sandstone interval of bay-head delta deposition. Porosity and permeability distributions of layers generated in the Petrel model were exported to the simulation model. An OOIP estimation of 67 MMBO in Grieve Muddy channel sand has resulted from a simulation history matching based on the full-field material balance. History matching also reveals that about one MMSTBO of oil and 8.2 BSCF of gas have moved down from the overlain low-permeability sandstone interval into the Muddy channel sand interval during the reservoir depletion.

Grieve oil field was discovered in August 1954. The field is located in southeastern Wind River Basin, central Wyoming, and is currently operated by Elk Petroleum Inc. (Elk Petroleum), Figure 1. The producing oil reservoir is a stratigraphic/structural trap at a depth of 6,900 ft in the Lower Cretaceous, valley-fill and channelized, Muddy sandstone. The average structural dip in the Grieve area is about 15 degrees to the northeast.

This Tensleep Formation Fracture Study compendium contains the field studies, core analyses and literature reviews conducted over the 2007-2010 period in an effort to understand the characteristics and distributions of fractures and their influence on fluid flow within Tensleep Formation reservoirs. The studies reported here are the results of a large-scale project on fractures in the Tensleep Formation in Wyoming initiated by the Enhanced Oil Recovery Institute (EORI) at the University of Wyoming. The supporting data are also available through EORI and can be utilized in a variety of modeling software.

• The thermodynamic characterization of reservoir and injected fluids allows us to perform rigorous analyses of the oil recovery processes.
• A continuous program that will reveal important factors that are still unknown or not well understood and affecting the efficiency of oil recovery.
• A synthesis of theoretical and experimental components.