Tubing and control line hydrostatic-insensitive single control line safety valve

A method for operating a safety valve, the method comprises:

• providing the safety valve to a wellbore having a hydrostatic pressure;
• applying pressure to the safety valve with a single control line;
• wherein the safety valve comprises an accumulator in fluidic communication with the control line such that pressure acting on the accumulator is fluidically connected to pressure in the control line;
• wherein the safety valve is insensitive to the hydrostatic pressure;
• wherein the safety valve comprises:
• an operating piston configured to translate axially along the length of the safety valve;
• a balance piston configured to translate axially along the length of the safety valve;
• wherein the balance piston is coupled to the operating piston such that the operating piston and the balance piston translate axially at the same time;
• a control line descending from an uphole surface;
• wherein the control line forms three flow paths;
• wherein the first flow path of the control line is coupled to a check valve;
• wherein the second flow path of the control is coupled to a poppet valve;
• wherein the third flow path is coupled to a flow restrictor;
• a pressure lock flow path comprising three segments;
• wherein the first segment of the pressure lock flow path is coupled to the check valve;
• wherein the second segment of the pressure lock flow path is coupled to the poppet valve;
• wherein the third segment of the pressure lock flow path is coupled to the operating piston;
• a balance pressure line comprising four segments;
• wherein the first segment of the balance pressure line is coupled to the poppet valve;
• wherein the second segment of the balance pressure line is coupled to the flow restrictor;
• wherein the third segment of the balance pressure line is coupled to the accumulator;
• wherein the fourth segment of the balance pressure line is coupled to the balance piston;
• the check valve;
• the poppet valve coupled;
• and
• the flow restrictor;
• and
• wherein the method further comprises applying pressure to the poppet valve from the second flow path of the control line to crack the poppet valve;
• building pressure in the pressure lock flow path to translate the operating piston upon cracking the poppet valve;
• wherein translation of the operating piston also translates the coupled balanced piston;
• and
• building pressure in the balance pressure line from the third flow path of the control line to close the poppet valve;
• wherein closing the poppet valve locks in the pressure in the pressure lock flow path to maintain the balance piston in a translated position.

A system for operating a safety valve, the system comprising:

• a safety valve comprising:
• an operating piston configured to translate axially along the length of the safety valve;
• a balance piston configured to translate axially along the length of the safety valve;
• wherein the balance piston in coupled to the operating piston such that the operating piston and the balance piston translate axially at the same direction and time;
• a control line descending from an uphole surface;
• wherein the control line forms three flow paths;
• wherein the first flow path of the control line is coupled to a check valve;
• wherein the second flow path of the control line is coupled to a poppet valve;
• wherein the third flow path is coupled to a flow restrictor;
• a pressure lock flow path comprising three segments;
• wherein the first segment of the pressure lock flow path is coupled to the check valve;
• wherein the second segment of the pressure lock flow path is coupled to the poppet valve;
• wherein the third segment of the pressure lock flow path is coupled to the operating piston;
• a balance pressure line comprising four segments;
• wherein the first segment of the balance pressure line is coupled to the poppet valve;
• wherein the second segment of the balance pressure line is coupled to the flow restrictor;
• wherein the third segment of the balance pressure line is coupled to an accumulator;
• wherein the fourth segment of the balance pressure line is coupled to the balance piston;
• the check valve;
• the poppet valve;
• the flow restrictor;
• and
• the accumulator;
• a spring coupled to the operating piston of the safety valve;
• and
• a sliding sleeve coupled to the spring.