Method of oil recovery from underground reservoirs
AssigneeGarrett Energy Research & Engineering Inc.
InventorDavid R. Pegg
Life of this patent
Estimating the term…
Abstract
Oil is recovered from underground reservoirs using hydrocarbons produced from cracking equipment located near the site. The equipment is operated at pressures proximate existing underground formation pressure to produce hydrocarbons for direct injection into the formation with reduced or no further compression. The hydrocarbons are injected at selected locations in the reservoir to pressurize the field, effectively reduce the oil viscosity and cause its flow into production wells. Specialized field cracking equipment, such as units for simple, small scale, low fouling operation that circulate heavy coke slurries, may be used to produce the hydrocarbons for injection.
Claims23
A method of oil recovery comprising:
- providing a field oil cracking unit near an oil formation having one or more wells, said cracking unit adapted to produce light and intermediate hydrocarbons at pressures for direct injection into the oil formation;
- said cracking unit comprising a cracker connected to said wells for cracking oil, said cracker including an overhead condensing means for separating said light from the intermediate or heavier hydrocarbons;
- said cracker comprising a thermal cracking device for small scale, high pressure hydrocarbon liquid phase cracking from a slurry having a high coke density employing the characteristics of a growth-type crystallizer;
- said device including a cracker chamber having an effective volume to provide a high liquid residence time per pass and a long coke residence time;
- heating means including heater tubes through which said slurry passes;
- means to circulate said slurry through said tubes whereby a low temperature differential between said slurry and tubes will be maintained to minimize fouling and control coking;
- contacting oil in said formation with the light and intermediate hydrocarbons by injecting said hydrocarbons into the formation through at least one of said wells;
- and
- displacing said oil in the formation with said hydrocarbons and causing flow of the oil to at least one of said wells.
A method of withdrawing oil from an underground oil-bearing strata penetrated by wells comprising the steps of
- providing field cracking equipment near said strata adapted to receive and convert oil feed to light hydrocarbons at pressures such that they may be injected into the existing strata;
- diluting the crude oil in said strata with said hydrocarbons;
- displacing the diluted crude oil with said hydrocarbons at sufficient pressure to cause said diluted crude oil to flow from said strata into withdrawal wells;
- said field cracking equipment including a cracker connected by an overhed line to a separation means for separating the light hydrocarbons from other hydrocarbons, said light hydrocarbons containing predominantly one to eight carbon atoms;
- said cracker comprising a thermal cracking device for small scale, high pressure hydrocarbon liquid phase cracking from a slurry having a high coke density employing the characteristics of a growth-type crystallizer;
- said device including a cracker chamber having an effective volume to provide a high liquid residence time per pass and a long coke residence time;
- heating means including heater tubes through which said slurry passes;
- and,
- means to circulate said slurry through said tubes whereby a low temperature differential between said slurry and tubes will be maintained to minimize fouling and control coking.
Dependencies are inferred from the claim text.