Method for producing natural gas from gas hydrates
A method for producing natural gas from subterranean gas hydrate deposits. A first injection wellbore includes a lateral section that extends into a subterranean geothermal zone. A second production wellbore includes a lateral section that extends into a subterranean gas hydrate zone. Water pumped into the first injection wellbore is heated by heat energy from the subterranean geothermal zone and is thereafter injected into the subterranean gas hydrate zone. The heated water injected into the subterranean gas hydrate zone is used to generate natural gas from gas hydrate deposits. The generated natural gas and injected water are recovered from the subterranean gas hydrate zone through the second production wellbore.
1 . A method for producing natural gas from gas hydrate deposits, the method comprising:
a) providing an injection wellbore comprising a vertical section and a horizontal section, wherein said horizontal section of said injection wellbore at least partially extends into a subterranean geothermal zone;
b) providing an injection tubing string in said injection wellbore, wherein said injection tubing string has an inner through bore and defines an annular space along an outer surface of said injection tubing string, and wherein said annular space of said injection wellbore is in fluid communication with a subterranean gas hydrate zone;
c) providing a production wellbore comprising a vertical section and a horizontal section, wherein said horizontal section of said production wellbore at least partially extends into said subterranean gas hydrate zone;
d) providing a production tubing string in said vertical section of said production wellbore, wherein said production tubing string has an inner through bore and defines an annular space along an outer surface of said production tubing string, wherein said inner through bore of said production tubing string and said annular space of said production wellbore are isolated from each other;
e) pumping water through the inner through bore of said injection tubing string of said injection wellbore and into said annular space of said injection wellbore;
f) heating said water in said annular space of said injection wellbore using heat energy from said geothermal zone;
g) injecting said heated water from said annular space of said injection wellbore into said subterranean gas hydrate zone;
h) producing natural gas from said subterranean gas hydrate zone through said horizontal section and said annular space of said production wellbore;
i) recovering injected water from said subterranean gas hydrate zone through said inner through bore of said production tubing string; and
j) regulating flow rate of said recovered water using a wellhead choke.