Bp Corporation North America Inc.

Atlantic Richfield Company

Bp Exploration Operating Company Limited

Patrick Lee McGuire

Ian Ralph Collins

Kevin John Webb

Gary Russell Jerauld

Euthimios Vittoratos

Arnaud Lager

Joseph L Anders

Method for increasing recovery of crude oil from a reservoir having an oil-bearing porous subterranean formation with a permeability of greater than 10 millidarcies, the formation including rock having pores with crude oil and connate water having a multivalent cation content present within the pores. The crude oil in the formation has an API gravity of less than 30&#xb0;, a viscosity greater than 1 centipoise, and undissolved solids suspended therein. Injection water having undissolved solids suspended therein, a total dissolved solids content of 30,000 ppm or less and a multivalent cation content such that a ratio of the multivalent cation content of the injection water to the multivalent cation content of the connate water is less than 0.9, is injected into the formation, to produce an emulsion within the formation. The emulsion has an undissolved suspended solids content of at least 0.05% by weight of emulsion.

Hydrocarbon recovery process

A method for generating softened injection water (A) (i) introducing source water having a dissolved solids content of up to 15,000 mg/liter and a multivalent cation content of greater than 40 mg/liter to a bed of cation exchange resin in monovalent cation form, (ii) passing the water through the bed so that at least a portion of the multivalent cations in the water are replaced by monovalent cations from the resin, and (iii) withdrawing the softened injection water having a multivalent cation content of up to 40 mg/liter; (B) regenerating the cation exchange resin by (i) introducing a regenerating brine to the vessel, (ii) passing the brine through the bed and (iii) withdrawing a brine containing displaced multivalent cations, wherein the brine is a naturally occurring high salinity water having a concentration of cations such that the Softening Limit for the source water is up to 40 mg/liter of multivalent cations.

Method for generating softened injection water

Hydrocarbons are recovered from subterranean formations by waterflooding. The method comprises passing an aqueous displacement fluid via an injection well through a porous and permeable sandstone formation to release oil and recovering said released oil from a production well spaced from said injection well, wherein (a) the sandstone formation comprises at least one mineral having a negative zeta potential under the formation conditions; (b) oil and connate water are present in the pores of the formation; and (c) the fraction of the divalent cation content of the said aqueous displacement fluid to the divalent cation content of said connate water is less than 1.

A method for recovering waterflood residual oil from a waterflooded oil-bearing subterranean formation penetrated from an earth surface by at least one well by injecting an oil miscible solvent into a waterflood residual oil-bearing lower portion of the oil-bearing subterranean formation through a well completed for injection of the oil miscible solvent into the lower portion of the oil-bearing formation; continuing the injection of the oil miscible solvent into the lower portion of the oil-bearing formation for a period of time equal to at least one week; recompleting the well for production of quantities of the oil miscible solvent and quantities of waterflood residual oil from an upper portion of the oil-bearing formation; and producing quantities of the oil miscible solvent and waterflood residual oil from the upper portion of the oil-bearing formation. The formation may have previously been both waterflooded and oil miscible solvent flooded. The solvent may be injected through a horizontal well and solvent and oil may be recovered through a plurality of wells completed to produce oil and solvent from the upper portion of the oil-bearing formation.

Method for recovering waterflood residual oil

A method for recovering oil from a gravity drainage oil-bearing formation from which at least a major portion of the oil in place has been recovered through at least one production well penetrating the formation from the surface, the method comprising injecting an oil miscible solvent having a density slightly greater than a gas contained in a gas cap above the oil liquid level in the formation through a production well completed to inject the oil miscible solvent into an upper portion of the formation for a period of time equal to at least one week; recompleting the well for the production of oil from a lower portion of the formation; and producing oil through the well from the lower portion of the formation.

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Eagle River, AK, United States of America

Patrick Lee McGuire