Microbial enhanced oil recovery delivery systems and methods

A method of microbial enhanced oil recovery from a wellbore in an oil-bearing formation, said method comprising:

• injecting water into said oil-bearing formation via a tubing string in said wellbore;
• and
• introducing oxygen into said oil-bearing formation for consumption by microbes in said oil-bearing formation, wherein said oxygen introduction comprises introducing a fluid comprising oxygen into said oil-bearing formation without having said introduced oxygen contact a wall of said tubing string and without having said introduced oxygen contact said injected water when said injected water is within said tubing string, wherein said oxygen introduction comprises injecting said fluid comprising oxygen via a capillary tubing into said oil-bearing formation;
• and
• injecting nutrients into said oil-bearing formation via said capillary tubing.

A delivery system for microbial enhanced oil recovery from an oil-bearing formation, said system comprising:

• a water supply system configured to supply water to a wellhead of said oil bearing formation;
• a tubing string within a wellbore, said tubing string configured to transport said water from said wellhead to said oil-bearing formation;
• an oxygen supply system configured to supply gaseous oxygen for delivery to said oil-bearing formation;
• and
• a capillary tubing connected to said oxygen supply system, said capillary tubing configured to:
• deliver gaseous oxygen from said oxygen supply system to said oil-bearing formation, prevent said gaseous oxygen from contacting a wall of said tubing string, and prevent said gaseous oxygen from contacting liquid within said tubing string during said delivery.

A delivery system for microbial enhanced oil recovery from an oil-bearing formation, said system comprising:

• a water supply system configured to supply water to a wellhead of said oil bearing formation;
• a tubing string within a wellbore, said tubing string configured to transport said injection water from said wellhead to said oil-bearing formation;
• an oxygen supply system configured to dissolve gaseous oxygen in a fluid while said fluid is in surface equipment;
• and
• a capillary tubing configured to deliver said fluid comprising oxygen from said surface equipment to said oil-bearing formation, prevent said oxygen from contacting the walls of said tubing string, and prevent said oxygen from contacting liquid within said tubing string during said delivery.