CAMTOP API 16C Choke Manifold | API 6A FLS Gate Valves & Buffer Chamber | NACE MR0175

Description

The CAMTOP API 16C Choke Manifold is a high-pressure wellhead flow-control assembly engineered to safely reduce and regulate wellhead pressure during drilling, completion and well-testing operations. It provides maximum operational versatility by combining API 6A / API 16C monogrammed FLS gate valves, manual and hydraulic drilling chokes, and an integrated buffer chamber on a single transport-ready skid — ready to plug into any BOP stack on land or offshore.

During drilling, when the blowout preventers close and circulation must continue through a controlled path, the CAMTOP Choke Manifold diverts mud return through a series of manually- or hydraulically-actuated choke valves to safely bleed off wellbore pressure while protecting downstream separation equipment. The system can be configured for single or dual isolation valve arrangements — the latter providing a double barrier between process fluids and the atmosphere when changing chokes or during sand clean-up operations.

Each CAMTOP Choke Manifold is built to API Spec 16C and API Spec 6A standards, with all pressure-containing and well-wetted materials conforming to NACE MR0175 / ISO 15156 for sour-service compatibility. Available configurations cover the full spectrum of high-pressure drilling from 3,000 psi to 15,000 psi working pressure, with bore sizes from 2-1/16″ through 4-1/16″, and PSL-1 through PSL-3G performance levels. Manual, hydraulic, electric, and pneumatic actuation, plus full remote-control integration, make CAMTOP choke manifolds equally suited for land rigs, offshore platforms, and frac spreads.

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Key Features

• API 16C / API 6A Monogrammed Components — Every pressure-containing part is manufactured and certified to API 16C (Choke and Kill Equipment) and API 6A (Wellhead and Christmas Tree Equipment) standards, with full traceability and monogramming on each valve and choke.
• Working Pressure up to 15,000 psi — Standard configurations cover 3,000 / 5,000 / 10,000 / 15,000 psi working pressure; optional 20,000 psi units available for ultra-high-pressure drilling applications.
• Bore Sizes 2-1/16″ to 4-1/16″ — Standard API flange end connections (2-1/16″, 3-1/8″, 4-1/16″) match the BOP outlet dimensions of every major rig platform in service today.
• Multiple Actuation Options — Manual, hydraulic, electric, and pneumatic actuation available for both gate valves and choke valves; fail-safe gate valves can be specified for redundant shut-in protection.
• Integrated Buffer Chamber — Built-in buffer chamber (minimum 7-1/16″ ID) absorbs downstream gas expansion and reduces manifold outlet velocity, with multiple outlets sized to ensure single-outlet failure does not affect manifold operation.
• Stainless Steel & Inconel 625 Ring Grooves — Optional SS316 / Inconel 625 inlay available for sour-service (H₂S) and CO₂-bearing wells where corrosion resistance is critical.
• Erosion-Resistant Blast Spools — Hardfaced or ceramic-lined blast spools installed downstream of chokes protect downstream piping from sand-cut erosion during well clean-up operations.
• Single & Dual Isolation Valve Arrangements — Standard single isolation for general service; dual isolation (double barrier) for high-pressure and sand clean-up applications where changing chokes without venting to atmosphere is required.
• Remote Control & Local Panel — Full remote operation capability via choke control panel with local and remote access and manual override; integrates with standard rig SCADA / DCS systems.
• Adjustable, Positive & Hydraulic Chokes — Manifold can be fitted with manually-adjustable needle-and-seat chokes, fixed-orifice positive chokes, or hydraulic adjustable chokes per API 16C.
• NACE MR0175 / ISO 15156 Compliant — All pressure-containing and well-wetted materials conform to NACE MR0175 / ISO 15156 for sour-service environments; service classification from Standard to extreme sour H₂S.
• Skid Options: Stand-Alone, Telescoping & Split — Available as stand-alone skid, telescoping skid, non-telescoping skid, or split-skid design for helicopter-transportable assemblies on offshore platforms.
• PSL-1 through PSL-3G Performance Levels — Manufactured to API 6A Product Specification Levels PSL-1, PSL-2, PSL-3 and PSL-3G, with Material Classes AA, BB, CC, DD and EE available for any service requirement.
• Temperature Rating K to U (-60°C to +121°C) — Full API 6A temperature class coverage including cold-weather arctic service (Class K) and high-temperature geothermal / steam-flood service (Class U).

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Technical Specifications

Parameter	Value
Product Designation	API 16C Choke Manifold (Choke & Kill Manifold System)
Design Standard	API Spec 16C (Choke & Kill Equipment), API Spec 6A (Wellhead & Tree Equipment)
Bore Sizes (Flange End)	2-1/16″, 2-9/16″, 3-1/8″, 4-1/16″ (custom sizes on request)
Working Pressure Ratings	3,000 psi / 5,000 psi / 10,000 psi / 15,000 psi (up to 20,000 psi on request)
Hydrostatic Test Pressure	1.5 × Working Pressure per API 6A / 16C
Product Specification Level (PSL)	PSL-1, PSL-2, PSL-3, PSL-3G
Performance Class (PR)	PR1 (standard), PR2 (enhanced)
Material Classes	AA (General Service), BB, CC, DD, EE (Sour Service)
Temperature Rating (API 6A)	Class K (-60°C) through Class U (+121°C)
Service Condition	Standard / Sour / NACE MR0175 / ISO 15156
End Connections	API 6A flanges (Studded or Flanged), ANSI B16.5 RF / RTJ optional
Ring Groove Material	Carbon steel standard; SS316 or Inconel 625 inlay for sour service
Gate Valve Type	FLS (Full Opening) gate valves per API 6A / 16C
Choke Valve Types	Manual Adjustable (needle & seat), Positive (fixed orifice), Hydraulic Adjustable
Actuation Options	Manual, Hydraulic, Pneumatic, Electric (for gate valves & chokes)
Fail-Safe Valves	Manual / Hydraulic / Pneumatic fail-safe gate valves available
Buffer Chamber	Minimum ID 7-1/16″, multi-outlet configuration; split-chamber design optional
Blast Spools	Erosion-resistant (hardfaced / ceramic-lined) downstream of chokes
Skid Configuration	Stand-Alone, Telescoping, Non-Telescoping, Split Skid (helicopter-transportable)
Control System	Local control panel, remote access, manual override, SCADA / DCS ready
Instrumentation	Pressure gauges (analog & digital), pressure transmitters, ESD ready
Material Certificates	EN 10204 3.1 / 3.2 supplied; witnessed inspection by third party (BV / SGS / DNV) available
Manufacturing Code Stamp	API 16C & API 6A monogram on each pressure-containing component
Applicable Service	Drilling, Completion, Well Testing, Workover, Production (HPHT & Sour)
Color (Standard)	Customer-specified (Blue RAL 5015 standard, other colors optional)
Approximate Lead Time	90–120 days for standard configurations; 150+ days for custom-engineered units

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Model Selection — Bore Size × Working Pressure

The CAMTOP Choke Manifold family covers 12 standard configurations across 3 bore sizes and 4 working-pressure ratings. Custom combinations and higher-pressure units (up to 20,000 psi) are available on request.

Model	Bore Size	Working Pressure	PSL / PR Class	Material Class	Typical Application
CM-2-3M	2-1/16″	3,000 psi	PSL-1 / PR1	AA / BB	Standard Drilling, Well Test
CM-2-5M	2-1/16″	5,000 psi	PSL-1 / PR1	AA / BB / CC	Standard Drilling, Completion
CM-2-10M	2-1/16″	10,000 psi	PSL-2 / PR1	AA / BB / CC / DD	HP Drilling, Acidizing
CM-2-15M	2-1/16″	15,000 psi	PSL-3 / PR2	BB / CC / DD / EE	HPHT Drilling, HP Well Test
CM-3-3M	3-1/8″	3,000 psi	PSL-1 / PR1	AA / BB	Standard Drilling, Workover
CM-3-5M	3-1/8″	5,000 psi	PSL-2 / PR1	AA / BB / CC	Drilling, Well Test, Acidizing
CM-3-10M	3-1/8″	10,000 psi	PSL-2 / PR2	BB / CC / DD	HP Drilling, Fracturing Support
CM-3-15M	3-1/8″	15,000 psi	PSL-3 / PR2	BB / CC / DD / EE	HPHT Drilling, Sour Service
CM-4-3M	4-1/16″	3,000 psi	PSL-2 / PR1	AA / BB	High-Flow Drilling, Workover
CM-4-5M	4-1/16″	5,000 psi	PSL-2 / PR2	AA / BB / CC / DD	High-Flow HP Drilling, Fracturing
CM-4-10M	4-1/16″	10,000 psi	PSL-3 / PR2	BB / CC / DD / EE	Ultra HP Drilling, HPHT Service
CM-4-15M	4-1/16″	15,000 psi	PSL-3G / PR2	CC / DD / EE	Ultra HPHT / Critical Sour Service

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Working Principle & Operational Configurations

A choke manifold is installed downstream of the BOP outlet and upstream of the mud-gas separator / flare line. Its function is to throttle the flow from the well when the BOP is closed and circulation must continue, or to control wellbore pressure during kicks, well clean-up and production testing.

Choke & Kill Operation

1. During Drilling: When the BOP is closed, mud return is diverted through the choke manifold. The adjustable choke (manual, hydraulic, or remote-controlled) throttles the flow and regulates downstream pressure.
2. During a Kick: If formation fluids enter the wellbore, the choke manifold controls the casing pressure while the kill line pumps heavy mud down the annulus to restore hydrostatic balance.
3. Well Clean-Up & Blow-Off: After perforation, high-rate flow is directed through the choke manifold to the burn pit or separator. Erosion-resistant blast spools protect downstream piping from sand-cut erosion.
4. Positive Choke Insertion: For high-rate or erosive service, a fixed-orifice positive choke bean is inserted into the choke body, providing repeatable flow control without operator intervention.
5. Buffer Chamber Function: The integrated buffer chamber absorbs downstream gas expansion from sudden choke closure, preventing hydraulic shock and water-hammer damage to downstream equipment.

Single vs. Dual Isolation

• Single Isolation — One gate valve upstream and one downstream of each choke. Standard for general drilling and well-test operations.
• Dual Isolation — Two gate valves in series on each side of the choke, providing a double barrier between process fluids and the atmosphere. Mandatory for high-pressure and sand clean-up applications where chokes must be changed without depressurizing the manifold.

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Buffer Chamber — Design & Function

The CAMTOP buffer chamber is a multi-outlet header with API-spec flanged or studded connections. Its upstream pressure rating is equal to or higher than the BOP; equipment downstream of the chokes has a pressure rating lower than the choke lines and BOP.

• Minimum ID 7-1/16″ for proper gas-expansion absorption
• Multiple Outlets: Ensures any single-outlet failure does not affect overall manifold operations
• Fluid Cushion on Blind Flanges: All blind flanges include fluid-cushion connection for safe pressure-equalisation during maintenance
• Split-Chamber Design (Optional): For helicopter-transportable assemblies on offshore platforms; can be assembled at the rig
• Function: Absorbs downstream gas expansion → reduces manifold outlet velocity → prevents hydraulic shock → protects flare line and separator

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Application Scenarios

• Drilling Wellhead Pressure Control — Primary use during drilling operations: throttles wellhead flow when BOP is closed and circulation continues; controls casing pressure during kicks.
• Well Kick Control & Circulation — When formation fluids enter the wellbore, the choke manifold regulates casing pressure while the kill line restores hydrostatic balance with heavy mud.
• Well Clean-Up Operations — After perforation or acidizing, high-rate flow is directed through the manifold to the burn pit; erosion-resistant blast spools protect downstream piping from sand-cut.
• Production Well Testing — Surface well-test manifolds assess reservoir potential under dynamic flow conditions; validates well performance during clean-up and commissioning.
• Fracturing Support (Frac) — High-rate pumping of fracturing fluid during unconventional shale-well stimulation; multiple manifolds stacked in parallel for high-rate frac spreads.
• Workover & Well Intervention — Pressure control during snubbing, coiled-tubing, wireline and other live-well interventions; safely handles wellbore pressure fluctuations.
• HPHT (High-Pressure High-Temperature) Drilling — Sour-service (H₂S / CO₂) and high-temperature applications using NACE MR0175 materials and Inconel 625 ring-groove inlays.
• Offshore Drilling Platforms — Compact, helicopter-transportable split-skid assemblies designed for offshore platforms where crane capacity and deck space are limited.

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Why Choose CAMTOP

• API 16C & API 6A Monogrammed — Every pressure-containing component bears the official API monogram, ensuring full compliance and acceptance on major rig platforms worldwide.
• Complete Pressure Range — Standard configurations from 3,000 to 15,000 psi WP; up to 20,000 psi available on request — covers every standard drilling and well-test operating envelope.
• Full Actuation Flexibility — Manual, hydraulic, pneumatic, electric actuation for both gate valves and chokes; fail-safe gate valves available for redundant shut-in protection.
• Comprehensive Sour-Service Capability — All pressure-containing and well-wetted materials conform to NACE MR0175 / ISO 15156; SS316 / Inconel 625 ring-groove inlays available for extreme sour environments.
• Engineering Customisation — CAMTOP engineers configure each manifold to your specific well conditions, skid dimensions, control philosophy and platform integration requirements.
• Global Field Support — CAMTOP field engineers can be deployed to support installation, commissioning and operator training at the rig site anywhere in the world on short notice.
• Fast Spare-Part Delivery — Standard spare parts (valve trim kits, choke beans, blast spools, pressure gauges) ship from Shanghai inventory within 5 business days to most destinations.

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Ordering Information

When ordering the CAMTOP API 16C Choke Manifold, please specify the following:

• Working Pressure Rating: 3,000 / 5,000 / 10,000 / 15,000 psi (or other)
• Bore Size: 2-1/16″ / 3-1/8″ / 4-1/16″ (or specify existing BOP outlet dimension)
• Configuration: Single or Dual Isolation; Manual / Hydraulic / Remote-actuated gate valves and chokes
• Material Class: AA / BB / CC / DD / EE (per API 6A); NACE MR0175 if sour service
• PSL Level & Temperature Class: PSL-1 / PSL-2 / PSL-3 / PSL-3G; K through U temperature rating
• End Connections: Studded (API 6A) or Flanged; specify ring-groove material if SS316 / Inconel 625 required
• Skid Configuration: Stand-alone, Telescoping, Non-Telescoping, or Split-skid (helicopter-transportable)
• Control System: Local control panel / Remote access / Manual override / SCADA / DCS integration
• Recommended 3-Year Spares: Gate valve trim kits, choke bean sets, blast spools, pressure gauges, packing sets