Cache Martini Oil Field
The Cache field is located in Montezuma County, Colorado, one mile east of the Utah state line and 10 miles east of the giant Aneth field. The Aneth field was discovered in 1956 and originally estimated to contain 1,500 million barrels of oil making it a classic “giant” oilfield. Extensive drilling and development activities were undertaken during the 1960s and secondary recovery was instituted only a few years after discovery. The field has been under waterflood since1961 and a major CO2 flood was begun on the McElmo Creek Unit in 1985. The field contains two reservoir units named the Desert Creek and the Ismay. In our opinion, the Aneth Field is an analogue for the Cache Field.
The Cache field was discovered in 1964, to date a total of 24 wells on an average 40-acre spacing have been drilled. Most of these wells were drilled throughout the 1960’s and most are now shut-in. Initial well production was between 1,400 – 3,000 BOPD per well but well production quickly declined, as is to be expected from a gas-solution drive reservoir. These rapid declines lead to the application of a secondary recovery method by implementing a water injection strategy. Short-term improvements in recoveries were initially seen in some wells as the water injection developed but current opinion is that significant damage was done to the cement bonds in the wells when the field operators used hot acid solutions to improve the reservoir performances within the oil zones. These hot acid solutions are most likely to have destroyed the integrity of the bonds and seals between the pipe and the wall rocks and allowed the water bearing formations to comingle with the oil bearing reservoirs.