If you choose to install a subsea gas lift system, you must design your system as approved in your DWOP or as follows:
(a) Design the gas lift supply pipeline in accordance with API RP 14C (incorporated by reference as specified in § 250.198) for the gas lift supply system located on the platform.
(b) Meet the applicable requirements in the following table:
If your subsea gas lift system
introduces the
lift gas to
the . . .
| Then you must install a
| In addition, you must
|
|---|
API Spec 6A and API Spec 6AV1 (both incorporated by
reference as specified in § 250.198) gas-lift shutdown valve (GLSDV), and . . .
| FSV on the
gas-lift supply
pipeline . . .
| PSHL on the gas-lift supply . . .
| API Spec 6A and API Spec 6AV1 manual isolation
valve . . .
|
|---|
| (1) Subsea pipelines, pipeline risers, or manifolds via an external gas lift pipeline or umbilical | Meet all of the requirements for the BSDV described in §§ 250.835 and 250.836 on the gas-lift supply pipeline. Locate the GLSDV within 10 feet of the first point of access to the gas-lift riser or topsides umbilical termination assembly (TUTA) (i.e., within 10 feet of the edge of the platform if the GLSDV is horizontal, or within 10 feet above the first accessible working deck, excluding the boat landing and above the splash zone, if the GLSDV is in the vertical run of a riser, or within 10 feet of the TUTA if using an umbilical) | on the platform upstream (in-board) of the GLSDV | pipeline on the platform downstream (out board) of the GLSDV | downstream (out board) of the PSHL and above the waterline. This valve does not have to be actuated | (i) Ensure that the MAOP of a subsea gas lift supply pipeline is equal to the MAOP of the production pipeline.
(ii) Install an actuated fail-safe close gas-lift isolation valve (GLIV) located at the point of intersection between the gas lift supply pipeline and the production pipeline, pipeline riser, or manifold.
(iii) Install the GLIV downstream of the underwater safety valve(s) (USV) and/or AIV(s).
|
| (2) Subsea well(s) through the casing string via an external gas lift pipeline or umbilical | Meet all of the requirements for the GLSDV described in §§ 250.835 and 250.836 on the gas-lift supply pipeline. Locate the GLSDV within 10 feet of the first point of access to the gas-lift riser or topsides umbilical termination assembly (TUTA) (i.e., within 10 feet of the edge of the platform if the GLSDV is horizontal, or within 10 feet above the first accessible working deck, excluding the boat landing and above the splash zone, if the GLSDV is in the vertical run of a riser, or within 10 feet of the TUTA if using an umbilical) | on the platform upstream (in-board) of the GLSDV | pipeline on the platform down- stream (out board) of the GLSDV | downstream (out board) of the PSHL and above the waterline. This valve does not have to be actuated. | (i) Install an actuated, fail-safe-closed GLIV on the gas lift supply pipeline near the wellhead to provide the dual function of containing annular pressure and shutting off the gas lift supply gas.
(ii) If your subsea tree or tubing head is equipped with an annulus master valve (AMV) or an annulus wing valve (AWV), one of these may be designated as the GLIV.
(iii) Consider installing the GLIV external to the subsea tree to facilitate repair and or replacement if necessary.
|
| (3) Pipeline risers via a gas-lift line contained within the pipeline riser | Meet all of the requirements for the GLSDV described in §§ 250.835(a), (b), and (d) and 250.836 on the gas-lift supply pipeline | upstream (in-board) of the GLSDV | flowline upstream (in-board) of the FSV | downstream (out board) of the GLSDV | (i) Ensure that the gas-lift supply flowline from the gas-lift compressor to the GLSDV is pressure-rated for the MAOP of the pipeline riser.
|
| | Attach the GLSDV by flanged connection directly to the ANSI/API Spec. 6A component used to suspend and seal the gas-lift line contained within the production riser. To facilitate the repair or replacement of the GLSDV or production riser BSDV, you may install a manual isolation valve between the GLSDV and the ANSI/API Spec. 6A component used to suspend and seal the gas-lift line contained within the production riser, or outboard of the production riser BSDV and inboard of the ANSI/API Spec. 6A component used to suspend and seal the gas-lift line contained within the production riser | | | | (ii) Ensure that any surface equipment associated with the gas-lift system is rated for the MAOP of the pipeline riser.
(iii) Ensure that the gas-lift compressor discharge pressure never exceeds the MAOP of the pipeline riser.
(iv) Suspend and seal the gas-lift flowline contained within the production riser in a flanged ANSI/API Spec. 6A component such as an ANSI/API Spec. 6A tubing head and tubing hanger or a component designed, constructed, tested, and installed to the requirements of ANSI/API Spec. 6A.
(v) Ensure that all potential leak paths upstream or near the production riser BSDV on the platform provide the same level of safety and environmental protection as the production riser BSDV.
(vi) Ensure that this complete assembly is fire-rated for 30 minutes. |
(c) Follow the valve closure times and hydraulic bleed requirements according to your approved DWOP for the following:
(1) Electro-hydraulic control system with gas lift,
(2) Electro-hydraulic control system with gas lift with loss of communications,
(3) Direct-hydraulic control system with gas lift.
(d) Follow the gas lift system valve testing requirements according to the following table:
| Type of gas lift system
| Valve
| Allowable leakage rate
| Testing frequency
|
|---|
| (1) Gas lifting a subsea pipeline, pipeline riser, or manifold via an external gas lift pipeline | GLSDV | Zero leakage | Monthly, not to exceed 6 weeks.
|
| | GLIV | N/A | Function tested quarterly, not to exceed 120 days.
|
| (2) Gas lifting a subsea well through the casing string via an external gas lift pipeline | GLSDV | Zero leakage | Monthly, not to exceed 6 weeks.
|
| | GLIV | 400 cc per minute of liquid or 15 scf per minute of gas. | Function tested quarterly, not to exceed 120 days
|
| (3) Gas lifting the pipeline riser via a gas lift line contained within the pipeline riser | GLSDV | Zero leakage | Monthly, not to exceed 6 weeks. |