EOR Performance and Modeling

Enhanced-oil-recovery (EOR) technologies have drawn increased interested because of the decreasing number of new-field discoveries, increasing number of maturing fields worldwide, and higher oil price, with the oil price peaking above USD 145/ bbl in July 2008. It is more important than ever to understand lessons learned from past EOR applications and to develop new technologies and methods. More than 200 papers on EOR were presented at various SPE conferences in 2008. The EOR feature is split this year: EOR Performance and Modeling herein and EOR Operations in June. I categorized EOR papers for this feature into the following seven technologies. • Wettability-alteration methods: surfactant imbibition for carbonate reservoirs, low-salinity waterflooding for sandstone reservoirs, and “smart water” for carbonate reservoirs. • Chemical-flooding methods for conventional light oil: polymer flooding, polymer/surfactant flooding, alkaline/surfactant/polymer flooding, and surfactantmicelle flooding. • EOR methods for heavy oil: steamflooding, in-situ combustion, steam-assisted gravity drainage, surfactant-alternating-gas, gas-assisted gravity drainage, thermalassisted/ gas-assisted gravity drainage, and alkaline/surfactant/polymer and alkali/ surfactant flooding. • Gas injection and CO2 sequestration: CO2 miscible and immiscible flooding, water-alternating-gas injection, and CO2 EOR and sequestration. • Conformance control: gel treatments and foam flooding. • Diagnosis and evaluation of EOR applications: seismic method, tracer injection, and mathematical modeling for reservoir heterogeneity and for induced fractures caused by water injection. • Other EOR methods: in-situ seismic stimulation, microbial EOR, electrical EOR for heavy oil, and others. The papers that I selected for this feature fall into the first four categories