R.P. Major

Depositionally and Diagenetically Controlled Reservoir Heterogeneity at Jordan Field

This article reports on the San Andres reservoir in the University Lands Jordan field which has produced 68 MMSTB (11 {times} 10{sup 6} stock-tank m{sup 3}) of the 182 MMSTB (29 {times} 10{sup 6} stock-tank m{sup 3}) of original oil place (OOIP); an estimated 44 MMSTB (7 {times} 10{sup 6} stock-tank m{sup 3}) of mobile oil remains in this reservoir. The reservoir is divided into four flow units on the basis of depositional textures and subsequent digenetic overprint. The locus of highest production corresponds to a trend of high reservoir storage capacity in Zone C, which has been affected by a permeability-increasing, carbonate-leaching digenetic alteration. This locus crosscuts structure. An area of low production corresponds to an area of highest reservoir storage capacity in Zone B, which has not been affected by this digenetic alteration. This low-production area is in an up-dip position but has been inefficiently swept by the waterflood.