CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to International Application Number PCT/US2018/067857 filed on Dec. 28, 2018, entitled “COMBINED CHEMICAL/BALANCE LINE,” which application is commonly assigned with this application and incorporated herein by reference in its entirety.

BACKGROUND

Surface-controlled subsurface safety valves (SCSSVs) are well known in the oil and gas industry and provide one of many failsafe mechanisms to prevent the uncontrolled release of wellbore fluids should a wellbore system experience a loss in containment. Typically, SCSSVs comprise a portion of a tubing string set in place during completion of a wellbore. Although a number of design variations are possible for subsurface safety valves, the vast majority are flapper-type valves that open and close in response to longitudinal movement of a flow tube. Since SCSSVs provide a failsafe mechanism, the default positioning of the flapper is usually closed in order to minimize the potential for inadvertent release of wellbore fluids. The flapper can be opened through various means of control from the earth's surface in order to provide a flow pathway for production to occur.

In many instances, the flow tube can be regulated from the earth's surface using a piston and rod assembly that may be hydraulically charged via a control line linked to a hydraulic manifold or control panel. The term “control line” will be used herein to refer to a hydraulic line configured to displace the flow tube of a subsurface safety valve downward upon pressurization, or otherwise to become further removed from the exit of a wellbore. When sufficient hydraulic pressure is conveyed to a SCSSV via the control line, the piston and rod assembly forces the flow tube downward, which causes the flapper to move into its open position upon overcoming forces that tend to keep the flapper closed (e.g., biasing springs, downhole pressure, and the like). When the hydraulic pressure is removed from the control line, the flapper can return to its default, closed position. A self-closing mechanism, such as a torsion spring, can also be present to promote closure of the flapper should a loss of hydraulic pressure occur.

Some SCSSVs also employ a second hydraulic line configured to counterbalance the effects of the control line and to provide an additional means of regulating the flow tube. The term “balance line” will be used herein to refer to a hydraulic line configured to displace the flow tube of a subsurface safety valve upward upon pressurization, or otherwise to become less removed from the exit of a wellbore. A balance line, when present, can operate in a similar manner to a control line and be controlled from the earth's surface.

In addition to the control line and balance line extending to the SCSSV, many configurations additionally employ a separate chemical line extending up to and/or past the SCSSV. The term “chemical line” will be used herein to refer to a hydraulic line configured to provide one or more different types of chemicals to a chemical injection system positioned within the wellbore.

Depending on operational considerations, an SCSSV may be placed hundreds to thousands of feet downhole. Accordingly, the control line and balance line, and when used the chemical line, must extend the hundreds of feet downhole to the SCSSV, and in the case of the chemical line, past the SCSSV. The cost of running multiple different lines to and/or past the SCSSV is significant. Accordingly, what is needed in the art is a SCSSV that does not experience the significant costs associated with existing SCSSVs.

