Heating apparatus

A method for withdrawing oil from an underground oil reservoir through a production wellbore, the method comprising the steps of:

• a. providing a pressure gain combustion apparatus operatively configured to heat a portion of the oil within the underground oil reservoir;
• i. wherein the pressure gain combustion apparatus comprises a combustion chamber in fluid communication with a fuel inlet, an air inlet, and an ignition system;
• ii. a fuel delivery system operatively configured to supply fuel to the combustion chamber and operatively configured to utilize liquid or gaseous fuel to the combustion chamber;
• iii. an air intake system operatively configured to draw air at ambient pressure and supply the combustion chamber of said apparatus with pressurized air;
• iv. the combustion chamber operatively configured to produce pressure gain combustion or detonation of the fuel;
• b. a heat exchange device operatively configured to draw heat from combusted gasses produced during combustion or detonation;
• c. the heat exchange device in direct physical contact with walls of the combustion chamber to heat a fluid within the heat exchange device, wherein the fluid within the heat exchange device is not in fluid communication with the combustion chamber;
• d. the combustion chamber within an underground wellbore wherein the combustion chamber is annularly surrounded by the wellbore;
• i. wherein the wellbore is in fluid communication with an underground reservoir;
• ii. wherein the wellbore is radially outward of the combustion chamber to allow transfer of the heated fluid radially outward from the outer surface of the combustion chamber directly through the wellbore into the reservoir;
• and
• iii. wherein the combustion chamber is in physical communication with an underground reservoir, so as to transfer pulses and shock waves thereto;
• e. providing a production wellbore in proximity to the heated portion of the oil within the underground oil reservoir;
• and
• f. withdrawing at least a portion of the heated oil from the reservoir through the production wellbore.

A pressure gain combustion apparatus comprising:

• a. a combustion chamber in fluid communication with a fuel inlet, an air inlet, and an ignition system;
• b. a fuel delivery system operatively configured to supply fuel to the combustion chamber and operatively configured to supply liquid or gaseous fuel to the combustion chamber;
• c. an air intake system in fluid communication with the combustion chamber, the air intake system supplying the combustion chamber with air;
• d. the combustion chamber operatively configured to produce pressure gain combustion or detonation of the fuel;
• e. a heat exchange device operatively configured to draw heat from combusted gasses produced during combustion or detonation;
• f. the heat exchange device in direct physical contact with walls of the combustion chamber to heat a fluid within the heat exchange device, wherein the fluid within the heat exchange device is not in fluid communication with the combustion chamber;
• g. the combustion chamber within an underground wellbore wherein the combustion chamber is annularly surrounded by the wellbore;
• i. wherein the wellbore is in fluid communication with an underground reservoir;
• ii. wherein the wellbore is radially outward of the combustion chamber to allow transfer of the heated fluid radially outward from the outer surface of the combustion chamber directly through the wellbore into the reservoir;
• and
• iii. wherein exhaust from the combustion chamber is in physical communication with an underground reservoir, so as to transfer pulses thereto.