Downhole steam generator with improved preheating/cooling features

• US 4,411,618 A
• Filed: 10/10/1980
• Issued: 10/25/1983
• Est. Priority Date: 10/10/1980
• Status: Expired due to Term

• Current Assignee: Anthony J. Mulac, Donald E. Hoke, Donaldson A. Burl
• Original Assignee: Anthony J. Mulac, Donald E. Hoke, Donaldson A. Burl
• Inventors: Donaldson, A. Burl, Hoke, Donald E., Mulac, Anthony J.
• Primary Examiner(s): Barrett, Lee E.
• Application Number:
  US06/195,966
• Time in Patent Office: 1,110 Days
• Field of Search: 431/158, 431/242, 431/243, 431/353, 431/190, 60/39.55, 60/730, 60/736, 166/59, 166/303, 175/14
• US Class Current: 431/190
• CPC Class Codes: E21B 36/02 using burners
• CPC Class Codes: E21B 43/24 using heat, e.g. steam injection
• CPC Class Codes: F23D 11/44 Preheating devices; Vaporising devices
• CPC Class Codes: F23M 5/085 using air or other gas as the cooling medium

Abstract

An apparatus for downhole steam generation employing dual-stage preheaters for liquid fuel and for the water. A first heat exchange jacket for the fuel surrounds the fuel/oxidant mixing section of the combustor assembly downstream of the fuel nozzle and contacts the top of the combustor unit of the combustor assembly, thereby receiving heat directly from the combustion of the fuel/oxidant. A second stage heat exchange jacket surrounds an upper portion of the oxidant supply line adjacent the fuel nozzle receiving further heat from the compression heat which results from pressurization of the oxidant. The combustor unit includes an inner combustor sleeve whose inner wall defines the combustion zone. The inner combustor sleeve is surrounded by two concentric water channels, one defined by the space between the inner combustor sleeve and an intermediate sleeve, and the second defined by the space between the intermediate sleeve and an outer cylindrical housing. The channels are connected by an annular passage adjacent the top of the combustor assembly and the countercurrent nature of the water flow provides efficient cooling of the inner combustor sleeve. An annular water ejector with a plurality of nozzles is provided to direct water downwardly into the combustor unit at the boundary of the combustion zone and along the lower section of the intermediate sleeve.

Claims

1. An apparatus for downhole steam generation, comprising an oxidant supply means for supplying oxidant downhole;

a combustion assembly adaptable for being lowered downhole and comprising a fuel/oxidant mixing section, a combustor unit and a top cap member made of heat conductive material for operably connecting the fuel/oxidant mixing section to the combustor unit;

a fuel supply means for providing fuel to said fuel/oxidant mixing section and comprising a first heat exchanger jacket made of heat conductive material surrounding the fuel/oxidant mixing section and secured to the top cap member and having a fuel inlet port for receiving fuel therein, and a second heat exchanger jacket in communication with the first heat exchanger jacket, said second heat exchanger jacket surrounding the fuel/oxidant mixing section and having a fuel outlet port in communication with the fuel/oxidant mixing chamber;

an ignitor means connected to said combustor assembly for igniting the fuel/oxidant; and

water supply means completely surrounding and operably connected to said combustor unit for providing water to be converted to steam by the heat of combustion of the fuel/oxidant.

2. An apparatus for downhole steam generation as described in claim 1, wherein said oxidant supply means is constructed of heat conductive material, and directly contacts said top cap member, thereby providing heat conductive from said top cap member to the fuel in said first and second jackets.

3. An apparatus for downhole steam generation comprising:

a combustor assembly having a fuel/oxidant mixing section and a combustor unit;

an oxidant supply means connected to said fuel/oxidant mixing section;

a fuel supply means connected to said fuel/oxidant mixing section;

an ignitor means connected with said combustor unit;

a water supply means connected to said combustor unit for providing water to be converted to steam by the heat of combustion of the fuel/oxidant;

said combustor unit including an inner combustor sleeve having an inner wall defining a combustion zone;

an intermediate sleeve spaced concentrically with respect to said inner combustor sleeve, the space between said intermediate sleeve and said inner combustor sleeve connected to said water supply means and defining an annular water flow channel for said inner combustor means, said intermediate sleeve having a portion extending below said inner sleeve, said extending portion having an inner wall defining a steam generating zone; and

a water ejector means for controlling the flow of water through the annular water flow channel and comprising an annular spray injector member positioned between the lower end of the inner combustor sleeve and the intermediate sleeve said annular spray injector member comprising a plurality of spaced apertures around the outer periphery of said annular spray injector member adjacent the intermediate sleeve for ejecting said water downwardly along the inner wall of said intermediate sleeve, said annular spray injector member being capable of restricting the flow of water therethrough to ensure the continuous and even distribution of water throughout said water flow channel.