Abstract: Method of recovering oil from a subterranean oil-bearing reservoir by using an injection fluid containing a viscosifying polymer in a low salinity water. The low salinity water has a total dissolved solids (TDS) content of 15,000 ppmv or less, and the ratio of the multivalent cation content of the low salinity water to the multivalent cation content of the connate water of the reservoir is less than 1. The viscosity of the injection fluid is in the range of 3 to 200 cP, and the reservoir is penetrated by one or more injection wells and by one or more production wells. The method includes injecting the injection fluid into at least one of the injection wells in a slug size in the range of 0.4 to 1.5 pore volume (PV).

Abstract: A computer-implemented method for configuring operating conditions for at least one of desalination equipment and fluid injection equipment to be used in a low salinity waterflood on a hydrocarbon-bearing reservoir is provided. The reservoir is penetrable by an injection well and a production well. The method comprises deriving an ion diffusion distance value from: a diffusion coefficient indicative of a rate of diffusion of ions through relatively permeable layers of the reservoir when the low salinity water is present therein; and a residence time value indicative of the time required for the low salinity water to pass from the injection well to the production well through the reservoir; comparing the thickness of the relatively permeable layers to the derived ion diffusion distance value; generating an indication of the effectiveness of performing a low salinity waterflood; and configuring said operating conditions based on the indication of the effectiveness.

Abstract: A computer-implemented method for configuring operating conditions for at least one of desalination equipment and fluid injection equipment to be used in a low salinity waterflood on a hydrocarbon-bearing reservoir is provided. The reservoir is penetrable by an injection well and a production well. The method comprises deriving an ion diffusion distance value from: a diffusion coefficient indicative of a rate of diffusion of ions through relatively permeable layers of the reservoir when the low salinity water is present therein; and a residence time value indicative of the time required for the low salinity water to pass from the injection well to the production well through the reservoir; comparing the thickness of the relatively permeable layers to the derived ion diffusion distance value; generating an indication of the effectiveness of performing a low salinity waterflood; and configuring said operating conditions based on the indication of the effectiveness.

Abstract: A method of recovering oil from a subterranean oil-bearing reservoir uses an injection fluid comprising a viscosifying polymer in a low salinity water. The reservoir is penetrated by one or more injection wells and by one or more production wells. The method comprises injecting the injection fluid into at least one of the injection wells in a slug size in the range of 0.4 to 1.5 pore volumes (PV).

Abstract: Methods, apparatuses and computer readable instructions for determining the effectiveness of, and for performing, a low salinity waterflood. An ion diffusion distance value is determined based on the rate of diffusion of ions within the rock of a reservoir and the residency time of floodwater within the reservoir. The thickness of the layers of the reservoir are compared to this ion diffusion value to determine the effectiveness of performing a low salinity waterflood and also to enable the effective control of a waterflood and to assist in the determination of locations of wells.

Abstract: 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.

Abstract: 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.

Abstract: Method for increasing the recovery of crude oil from a reservoir containing at least one porous and permeable subterranean formation wherein the formation includes sandstone rock and at least one mineral that has a negative zeta potential under the reservoir conditions and wherein crude oil and connate water are present within the pores of the formation. The method is carried out by (A) injecting into the formation a slug of an aqueous displacement fluid that displaces crude oil from the surface of the pores of the formation wherein the pore volume (PV) of the slug of the aqueous displacement fluid is at least 0.

Abstract: 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.