Abstract:
A computer-implemented method for determining one or more operating modes for a crude oil displacement system is provided. The crude oil displacement system is arranged to inject an aqueous displacement fluid into one or more reservoirs, each reservoir comprising a porous and permeable rock formation, wherein crude oil and formation water are contained within a pore space of the rock formation. The crude oil displacement system is for use in displacing crude oil from the pore space of the rock formation. The computer-implemented method comprises the steps of receiving measurement data associated with one or more chemical characteristics of the displacement fluid and one or more chemical characteristics of the rock formation, the crude oil and the formation water of the one or more reservoirs, and inputting the measurement data and data representing a predetermined volume of oil into a computer-implemented predictive model. The predictive model is operated so as to generate predicted data indicative of a predicted additional amount of oil, compared to the predetermined volume of oil, that will be displaced by configuring the crude oil displacement system so as to inject the displacement fluid having the chemical characteristics into the one or more reservoirs. On the basis of the predicted data, the one or more operating modes of the crude oil displacement system are determined. A further computer-implemented method employing the predictive model in which predicted data indicative of one or more predicted chemical characteristics of the displacement fluid are generated is also provided. Additionally, a system for configuring a crude oil displacement system is provided.
Abstract:
A scale inhibition method comprising: (a) injecting a dispersion of seed particles of an insoluble mineral salt in an aqueous medium into a formation through an injection well wherein the seed particles have an equivalent spherical diameter of 100% less than 100 nm, preferably 100% less than 50 nm, more preferably 100% less than 25 nm and the aqueous medium has dissolved therein precipitate precursor ions that form a precipitate of the insoluble mineral salt when contacted with resident ions in the formation; (b) allowing the dispersion to percolate through the subterranean formation towards production well and producing the dispersion from the production well; and (c) controllably precipitating the insoluble mineral salt onto the seed particles so as to reduce the deposition of the insoluble mineral salt onto the walls of the porous formation and/or onto the surface in the production well and/or onto the surface downstream of the production well.
Abstract:
A method of recovering hydrocarbons from a porous subterranean hydrocarbon-bearing formation by: (a) reducing the salinity of a saline source water by reverse osmosis using a membrane having a first surface and a second surface by (i) feeding the saline source water to the first surface of the membrane, and (ii) removing treated water of reduced salinity from the second surface of the membrane; and (b) injecting the treated water into the formation; wherein the membrane is selectively permeable to water over dissolved solids such that when (i) the saline source water has a total dissolved solids content of at least 17,500 ppm, and (ii) the applied pressure across the membrane is greater than the osmotic pressure across the membrane and lies within the range 45 to 90 bar (4.5 to 9.0 MPa), the total dissolved solids content of the treated water is in the range 500 to 5000 ppm. Increased oil recovery can be achieved.
Abstract:
A method of recovering hydrocarbons from a porous subterranean hydrocarbon-bearing formation comprising the steps of : a) feeding to at least on reverse osmosis unit of a desalination assembly a high salinity water feed stream having a total dissolved solids content (total salinity) of at least 10,000 ppm; b) driving a portion of the high salinity water feed stream across a membrane in the reverse osmosis unit of the desalination assembly at a pressure above the osmotic pressure of the high salinity water feed stream while excluding at least a portion of the dissolved solids from crossing said membrane to produce a treated low salinity water product stream having a total salinity of less than 5,000 ppm and a concentrated waste brine stream wherein the hydrostatic head exerted by the high salinity water feed stream on the feed side of the membrane provides at least a major component of the pressure required to overcome the osmotic pressure; c) injecting the low salinity water product stream into the hydrocarbon-bearing formation from an injection well; d) displacing the hydrocarbons with the low salinity water product stream toward an associated production well; and e) recovering hydrocarbons from the formation via the production well.
Abstract:
A method for inhibiting the formation of gas hydrates within a fluid comprising a gaseous hydrocarbon phase, a liquid hydrocarbon phase and an aqueous phase which method comprises mixing a polymeric emulsifier and optionally a non-ionic non-polymeric co-emulsifier with the fluid prior to subjecting the fluid to conditions under which gas hydrates can be formed so as to generate a water-in-oil emulsion comprising a discontinuous aqueous phase, a continuous liquid hydrocarbon phase and a substantially gas impermeable interfacial layer comprising said polymeric emulsifier and optionally said non-ionic non-polymeric co-emulsifier wherein the aqueous phase is distributed in the continuous liquid hydrocarbon phase in the form of droplets and the substantially gas impermeable interfacial layer encapsulates said droplets.
Abstract:
A microemulsion comprising (i) an oil phase, (ii) an aqueous phase comprising an aqueous solution of a water soluble oil field or gas field production chemical or an aqueous dispersion of a water dispersible oil field or gas field production chemical and (iii) at least one surfactant, wherein the aqueous phase is distributed in the oil phase in the form of droplets having a diameter in the range 1 to 1000 mn or in the form of microdominans having at least one dimension of length, breath or thickness in the range 1 to 1000 nm.
Abstract:
A method of recovering or increasing the recovery of oil and/or gas from an underground formation involving injecting into the formation, preferably in the form of an aqueous solution, at least one mono alkyl ether of polyethylene glycol in which the alkyl group has 3-5 carbons and the polyethylene glycol contains 3-6 ethylene oxy units e.g. butyl ether of triethylene glycol. Especially preferred are mixtures comprising that and at least one mono alkyl ether of mono or di ethylene glycol e.g. a mixture of butyl triglycol ether, butyl tetraglycol ether, butyl pentaglycol ether and butyl diglycol ether. The method of the invention may be applied to well stimulation treatments such as water blocking, sand consolidation, sandstone acidizing and methods of increasing the recovery of oil such as tertiary oil recovery.
Abstract:
The invention relates to a process for increasing the effectiveness of production chemicals by reducing the number of squeezing and shut-in operations needed to increase the production rate from an oil well. The process includes injecting into an oil-bearing rock formation matrix a water-miscible formulation comprising: (a) a water-miscible surfactant which is an alkyltriglycol ether and (b) at least one water-miscible oil field or gas field production chemical. Components (a) and (b) are introduced either as a pre-formed, single, homogeneous composition, or simultaneously in parallel or sequentially in either order into the rock formation. After introduction of (a) and (b) into the oil-bearing rock formation, the well is shut-in for a period and, subsequently, the oil-bearing rock formation matrix is over-flushed with an oil.
Abstract:
A method of comparing a secondary oil recovery process with a tertiary oil recovery process, the secondary oil recovery process and the tertiary oil recovery process being applied to a substantially fluid-saturated porous medium containing an oil phase and an aqueous phase, the method comprising using relaxation time measurements in the calculation of a wettability index modification factor for the oil phase or the aqueous phase, thereby comparing the tertiary oil recovery process with the secondary oil recovery process.
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.