|Patent application number
|METHODS AND SYSTEMS FOR EVALUATION OF HYDROCARBON RESERVOIRS AND ASSOCIATED FLUIDS USING BIOLOGICAL TAGS AND REAL-TIME PCR - This invention relates in general to characterizing hydrocarbon reservoirs and/or determining flow properties of fluids associated with the reservoir-including fluids introduced into the reservoir to provide for hydrocarbon extraction-using biological tags and real-time polymerase chain reactions for tag detection. In embodiments of the present invention, one or more biological tags may be added to one or more liquids associated with the hydrocarbon reservoir and subsequently one or more liquid samples may be taken from locations associated with the hydrocarbon and the presence of the one or more biological tag may be qualitatively and/or quantitatively tested for in the samples using real-time PCR.
|PROVISION OF VISCOUS COMPOSITIONS BELOW GROUND - A thickened aqueous composition is delivered to a subterranean location accessible via a wellbore by steps of i. providing a biphasic aqueous mixture comprising two aqueous solutions which, at surface temperature and pressure, are able to co-exist as separate aqueous phases in contact with each other, ii. pumping said biphasic aqueous system down the wellbore to the subterranean location, and iii. converting the biphasic mixture below ground so that its phases combine into a single aqueous phase which is more viscous than the biphasic mixture. The two phases of the aqueous biphasic mixture contain dissolved solutes which segregate between the two phases such that at least one first solute is present at a greater concentration in the first aqueous phase than in the second aqueous phase while at least one second solute is present at a greater concentration in the second aqueous phase than in the first aqueous phase. The solute in the first phase may be a thickening polymer or other thickening material such as viscoelastic surfactant. The solute in the second phase may be a different polymer, surfactant or salt. Conversion to a single phase may be carried out in various ways including dilution, change in pH, change in salinity, increase in temperature and adsorption of one solute onto formation rock.
|METHODS AND APPARATUS TO CHANGE THE MOBILITY OF FORMATION FLUIDS USING THERMAL AND NON-THERMAL STIMULATION - Methods and apparatus to change the mobility of formation fluids using thermal and non-thermal stimulation are described. An example apparatus to simultaneously provide thermal and non-thermal stimulation to change a mobility of a fluid in a subsurface formation includes one or more containers to hold one or more reactants. Additionally, the example apparatus includes a reactor to initiate a chemical reaction with at least one of the reactants. Further, the example apparatus includes an injector to inject a product of the chemical reaction into a formation. The product of the chemical reaction includes heat and a gaseous diluent to change a mobility of a fluid in a subsurface formation.
|SOLVENT ASSISTED OIL RECOVERY - The recovery of oil from a reservoir is assisted by injecting a diluent into the reservoir formation to reduce the viscosity of the crude oil. This diluent is a mixture of a material which is an asphaltene precipitant, especially supercritical carbon dioxide, and a more polar material which comprises at least one aliphatic compound which includes at least one of a cycloaliphatic ring, an olefinic unsaturation, an ester or ether group. The inclusion of such an aliphatic compound which is more polar than the asphaltene precipitant reduces asphaltene precipitation and can enhance the efficiency of oil recovery when the precipitant is by supercritical carbon dioxide.
|FORECASTING ASPHALTIC PRECIPITATION - The magnitude of asphaltic precipitation when injecting a viscosity reducing diluent into a reservoir formation, notably to assist oil recovery therefrom, is forecast by (i) determining a relationship between asphaltic precipitation and a solubility parameter for the diluted oil, and then (ii) utilizing that relationship to forecast the magnitude of asphaltic precipitation when injecting a predetermined viscosity reducing diluent into the formation. Making this forecast may be followed by injecting a viscosity reducing diluent into the formation to assist oil recovery. The diluent may in particular be supercritical carbon dioxide or other asphaltene precipitant mixed with a more polar material in proportions designed by forecasting asphaltic precipitation by candidate materials in possible proportions.