Date of Award
Master of Science (MS)
This project aims to determine if methane (CH4) injection is more effective and economical than carbon dioxide (CO2) injection in a conventional dolomite reservoir by using the East Vacuum Grayburg-San Andres Unit (EVGSAU), Lea County, New Mexico as a model. This was done by simulating a CH4 and CO2 injection system and estimating the economics for each. CH4 injection has not been done at the EVGSAU, however CO2 has been used as a method of enhanced oil recovery.
The EVGSAU is located on the eastern side of the Vacuum Field, approximately 15 miles northwest of Hobbs in Lea County, New Mexico. The EVGSAU has produced over 126 million STB (42% OOIP) and nearly one-half of this production is because of Waterflood and CO2 injection (Harpole and Hallenbeck, 1996). This project used Eclipse 300 reservoir simulation software. The results were based on the simulation of three different cases: a base case, a CH4 case, and a CO2 case.
Reservoir data from the EVGSAU was used to build the static model, then a reservoir simulation of the three cases was run to determine which gas injection will result in enhanced oil production economically. The project economics were analyzed at a discount rate of 10% and evaluated at oil prices of $40/bbl, $50/bbl, and $60/bbl.
In the base case, two production wells P2 and I1 were produced without any gas injection. The CH4 case introduced the gas injection after two years of production in well I1, and injected a total of about 377,000 MSCF of CH4 at a cost of $4.00 per MCF. The CO2 case injected a total of about 387,000 MSCF of CO2 at a cost of $1.58 per MCF using the same injection/production schedule.
The CH4 case showed promise despite the higher cost per MCF and showed a higher increase in oil production to about 953,000 STB when compared to the 779,000 STB for the CO2 case, at a range of oil prices.
Ohalekwu, Charles, "MODELING THE EFFECT OF METHANE vs. CARBON DIOXIDE INJECTION ON OIL RECOVERY: CASE STUDY: THE EAST VACUUM GRAYBURG-SAN ANDRES UNIT, LEA COUNTY, NEW MEXICO" (2017). Graduate Theses & Non-Theses. 127.