A method of producing hydrocarbons from a subterranean hydrocarbon containing formation and reducing the flow of gas from a gas cap of the formation by passing a preselected volume of polymeric solution into the formation at an elevation lower than the gas cap, terminating the injecting of the polymeric solution, and producing fluid entering the well bore while at least intermittently injecting one of a gas-water admixture or volumes of gas and water into the gas cap.
A method for enhancing the recovery of liquid products from a wellbore having at least one laterally extending drain hole wellbore extending therefrom wherein a portion of the earth around the primary wellbore and a part of the drain hole wellbore is treated to render same essentially gas impermeable so that gas cannot prematurely cone into the primary wellbore, thereby enhancing the liquid recovery by way of the drain hole wellbore before gas reaches the drain hole wellbore.
The sweep efficiency of a two-phase gas/aqueous fluid in a formation is at a maximum when the volume ratio of gas to aqueous fluid corresponds to the minimum total mobility. By injecting gas and an aqueous liquid into a formation following a miscible flooding agent, the efficiency of the miscible flooding can be optimized.
The invention relates to a process for reducing or completely stopping a water inflow from a formation towards a producing well. The process according to the invention, using the injection of an aqueous dispersion of hydrosoluble polysaccharide in this producing well, blocks the water inflow without however decreasing the oil and gas flow towards this well. This process is particularly of high interest when the produced water is hot, e.g. at a temperature from 70.degree. to 130.degree. C., and/or salted, e.g. of a salt content of at least 30 g/l. This process is used for oil and/or gas production.
The permeability of subterranean oil-bearing formations is selectively reduced by the injection into the formation of the non-xanthan, anionic heteropolysaccharide S-130 produced by fermentation with a microorganism of the Alcaligenes species. The polymer forms shear-thinning, viscous solutions which selectively enter the more highly permeable regions of the formation and form a gel plug in them to reduce their permeability. The polymer forms gels which are stable under a wide range of reservoir conditions including high temperatures.
A process for recovering hydrocarbons from a subterranean hydrocarbon bearing formation penetrated by injection well and a production well includes the steps of injecting into the formation via an injection well an aqueous drive fluid comprising water and more than about 200 parts per million of Beta-(1.fwdarw.6)-D-glucan having an average molecular weight of more than about 2.times.10.sup.4 and comprising recurring units of the disaccharide gentiobiose: ##STR1## forcing said aqueous drive fluid through the formation and recovering hydrocarbons from the production well. The process also includes using a more concentrated solution of the glucan, more than about 2,000 parts per million, as a vertical conformance agent. The invention also includes a concentrate of the glucan in dimethylsulfoxide or in a 4 molar or higher concentration of aqueous urea which is diluted to form the aqueous drive fluid.
