North Kuwait Miscible Gas Eor Study

Abstract

Abstract KOC undertook a major leap in its FDP expansion programme by a very comprehensive Miscible Gas EOR feasibility screening review of the North Kuwait (NK) Sabiriya and Raudhatain oil fields. This paper will highlight the major findings of the Phase 1 of this project executed in 2008. Phase 1 evaluated available resources and data required for implementation of an EOR Pilot followed by a full field implementation. Main emphasis was to evaluate EOR injectant supply options and identify a most-likely first source with the associated risks. The workscope encompassed 4 major task items: ▪Investigate and rank alternative injectants for technical/economic feasibility, recovery efficiency & local availability point of view:–CO2-the quality, quantity, usability from the industries, factories, power-plants.–Mixtures of CO2 & NGL from Jurassic Condensate–Feasibility of other methods such as water-alternating-gas (WAG) or nitrogen (N2) injection–Evaluate the Heavy Oil Project emissions as injectants.▪Review PVT EOR laboratory studies conducted by KOC to date. Screen data for consistency and representativeness for PVT/EOS modeling in Phase-2 sector/pattern reservoir simulation work. Characterize fluid property variation vertically and areally. Make recommendations.▪Review the completion and facilities for suitability in a CO2 & other injectant environment. Provide a first pass assessment of the associated gross economics to implement EOR scenarios that may require changes/uprgades to the surface facilities and/or completions.▪Review coreflood SCAL studies, solubility and miscibility tests including WAG. Compare waterflood and immiscible/miscible tertiary gasflood relative permeability experiments. Establish the need for carbonate rock leaching experiments for CO2 injection. Establish the need for asphaltene precipitation experiments for heavy API grades. The study identified pure CO2 and CO2/NGL mixtures as the most plausible miscible gas options worth pursuing a pilot study. For each Miscible Injectant type, the source options & supply volumes and the CAPEX and OPEX cost estimates were established. Semi- analytical recovery models were used to evaluate the EOR recovery efficiencies of the individual reservoirs, net injectant requirements and product streams. The detailed EOR cost model was built using the actual KOC well and facility cost Database and CAPEX and O&M costs for the industrial sourced CO2. A preliminary economics was performed using input from both models above. A pilot project to demonstrate the feasibility of CO2 WAG was also proposed.