An injection well used in an in-situ combustion oil recovery process using a high oxygen concentration gas is completed with dual tubing strings to conduct the oxygen-containing gas and nitrogen separately down the well. The gases are mixed after they leave their separate tubing strings and enter the formation through perforations in the casing. If the bottomhole temperature of the well increases to a specific level, injection of the oxygen-containing gas is terminated and injection of the nitrogen is increased to a maximum amount until the bottomhole temperature decreases to a desired level for resuming in-situ combustion. In addition, injection of water into the bottom of the well is available as a back-up in the event that injection of the nitrogen does not lower the bottomhole temperature to the desired level. The use of the separate tubing strings for nitrogen and oxygen flow permits a faster bottomhole response to be obtained if undesired temperature increases take place downhole.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of my prior application, Ser. No. 553,925, filed Nov. 21, 1983, now abandoned the entire disclosure of which is incorporated into this application by reference.
A horizontal production well is located in the lower portion of a heavy viscous oil-bearing reservoir. A vertical injection well is located in the upper portion of the reservoir. Oxygen-enriched gas is injected down the injector well and ignited in the upper portion of the reservoir to create a combustion zone that reduces viscosity of oil in the reservoir as the combustion zone advances downwardly toward the horizontal production well, the reduced-viscosity oil draining into the horizontal production well under force of gravity.
There is a provided an apparatus and process for multi-zone profile control in a well including a wellbore intersecting at least one production zone, at least one injection tube, at least one insulation means, and at least one zone isolation means. Control media is injected through the injection tube, exiting at at least one control media exit of the injection tube and entering the production zone. The insulation means allow multiple zones to be injected simultaneously with control media of different temperatures and pressures.
A system is provided that monitors at the wellsite injection of additives into formation fluids recovered through wellbores and controls the supply of such additives from remote locations. The selected additive is supplied from a source at the wellsite into the wellbore via a suitable supply line. A flow meter in the supply line measures the flow rate of the additive through the supply line and generates signals representative of the flow rate. A controller at the wellsite determines the flow rate from the flow meter signals and in response thereto controls the flow rate of the additive to the well. The wellsite controller interfaces with a suitable two-way communication link and transmits signals and data representative of the flow rate and other parameters to a second remote controller. The remote controller transmits command signals to the wellsite controller representative of any change desired for the flow rate.
The present invention is a method and apparatus for the enhanced recovery of petroleum fluids from the subsurface by in situ combustion of the hydrocarbon deposit, from injection of an oxygen rich gas and drawing off a flue gas to control the rate and propagation of the combustion front to be predominantly horizontal and propagating vertically downwards guided by the vertical highly permeable hydraulic fractures. Multiple propped vertical hydraulic fractures are constructed from the well bore into the oil sand formation and filled with a highly permeable proppant containing hydrodesulfurization and thermal cracking catalysts. The oxygen rich gas is injected via the well bore into the top of the propped fractures, the in situ hydrocarbons are ignited by a downhole burner, and the generated flue gas extracted from the bottom of the propped fractures through the well bore and mobile oil gravity drains through the propped fractures to the bottom of the well bore and pumped to the surface. The combustion front is predominantly horizontal, providing good vertical and lateral sweep, due to the flue gas exhaust control provided by the highly permeable propped fractures.
Disclosed is a method for transporting blended crude oils comprising the steps of; (a) admixing a first crude oil with a second, different crude oil to form a crude oil admixture; (b) determining a first value representing the content of unprecipitated asphaltenes in the admixture; (c) holding the admixture for a period of time at standard conditions; (d) determining a second value representing the content of unprecipitated asphaltenes in the admixture; and (e) either: (i) transporting the admixture if the second value is the same as or within a predetermined range of the first value; or (ii) taking remedial action to prevent asphaltene precipitation prior to transporting if the second value is outside a predetermined range from the first value. Also disclosed is a method for estimating the storage stability of stored crude oils and crude oil admixtures.
