Repair & Maintenance
The safety, efficiency and economic viability of the oil and gas industry relies greatly on the transport and transfer of fluids from wellheads, through offshore process system piping and pipelines to refining facilities.
Regular inspection of pipeline ad process pipework can uncover defects or leaks that require modification or repair.
STATS collaborate with clients to ensure the specific requirements of any replacement or repair solution are fully understood and risk assessed. Solutions are engineered to meet the exacting design and operating parameters of the system.
STATS suite of repair and maintenance solutions are engineered to suit a wide variety of applications, both onshore and offshore. Our innovative repair and maintenance solutions enable operators to avoid or minimise shutdown time and reduce risk and expenditure.
Pressure Containment Clamp
Pressure Containment Clamps have been developed for process piping repair on oil and gas pipelines and process facilities. Installation can be undertaken with minimal disruption to the pipework or operation of the system to which they are fitted. The Pressure Containment Clamps are designed to be installed on damaged or leaking pipework, encapsulating the defect within the clamp body and regaining pressure integrity through mechanical seals engaging on the sound parent pipe.
Structural Repair Clamp
Structural Repair Clamps provide pressure containment and, where grout filled, radial support to the pipe. Where a Pressure Containment Clamp is fitted with taper locks it becomes a Structural Clamp to provide axial restraint.
The locks are configured as opposing sets which grip the pipe on either side of the defect. The locks are designed to transfer the full axial load of the pipe to the clamp body so allowing the clamp to withstand full pipeline separation loads.
- Size range: nominal pipe sizes 4” – 46”
- Pressure range: ambient to 300 Bar
- Nitrile seals compliant with corroded pipe OD
- Seal against pipeline using compression flanges
- Single seal with body cavity test capability
- Dual seal with annulus test capability
- Taper locks to prevent pipeline separation (Structural Clamp only)
- Optional polymeric grout sealant injection for radial support
Safely Securing and Recovering Caissons
STATS provide a range of caisson handling equipment for safely securing and recovering damaged or redundant caissons. Internal and External Lifting Tools cover a range of sizes to allow for safe and controlled caisson removal.
Due to their harsh environment, caissons can experience severe external corrosion at the waterline and galvanic corrosion / erosion at the pump string location. This can result in a lack of integrity, and occasionally result in part, or all, of the caisson becoming detached and lost to the seabed. Should a caisson become detached this would pose a serious safety concern for a platform and risk damage to subsea pipelines and equipment, impacting on production and reputation.
Internal and External Lifting Tools (ILT / ELT) are used to safely secure damaged or corroded caissons in position, until a planned retrieval back to the platform can be performed using the same tool. The compact size of the ELT and modular design of the ILT allows caissons to be recovered where space is limited. Caissons are securely lifted and cut into manageable sections before being safely removed from the platform.
ILT and ELT are available in common pipe sizes from 24” to 48”, with a safe working load up to 55 tonnes.
Read our case studies here
External Lifting Tool (ELT)
External Lifting Tools (ELT) are mounted to the outside of the caisson to provide secure lifting when internal access is obstructed or restricted due to pump strings or liners. The split section design allows easy installation, particularly in areas with restricted access or height. External gripping locks are hydraulically activated applying vertical load to the ELT which is set against the caisson.
Internal Lifting Tool (ILT)
Internal Lifting Tools (ILT) feature a twin module design, with each module containing its own set of independently controlled locks allowing operation in caissons with varying wall thicknesses. The taper-lock design provides a fail-safe locking system independent of hydraulic pressure, both locks provide axial and lateral stabilisation within the caisson. The modular design of the ILT allows the length between lock modules to be configured to client requirements, this also allows for easy installation particularly in areas of restricted access.
Lifting Tool Locking Features
ILT and ELT taper-locks are hydraulically actuated applying vertical load to the locks set against the caisson. ELT’s feature an array of hydraulic cylinders that are piped with two independently actuated hydraulic circuits. This arrangement has been engineered to allow four of the locks to be actuated via one hydraulic circuit and the remaining four locks to be actuated via the second hydraulic circuit. If the integrity of a hydraulic circuit was lost this contingency system would ensure 50% of the locks remained in their fully set condition with full communication. The tools are designed and tested to prove 50% lock engagement is sufficient for the tool to take its design load of 55 Tonne. The taper-lock design provides a fail-safe locking system independent of hydraulic pressure, once pre-tension is applied to the lifting tool the hydraulic actuation circuit becomes redundant. The lock engagement range allows lifting tools to be simply modified for use with a range of caisson sizes.
- Lifting tools retain caissons securely until planned repair or replacement
- Safe and controlled system for removing damaged or redundant caissons
- No production shutdown required during the removal operation
- Hydraulically actuated taper-locks grip wall of caisson
- ELT locks actuated with two independently hydraulic circuits
- Taper-lock design provides a fail-safe locking system independent of hydraulic pressure
- Designed and tested to prove 50% lock engagement is sufficient for the tool to hold maximum 55 Tonne design load
- Tension cable supplies self-energisation effect when pre-tension is applied
- Once pre-tension is applied to support rigging, hydraulic actuation circuit is redundant
- Tool removed by releasing tension and hydraulically de-activating locks
Internal Lifting Tool (ILT)
STATS Internal Lifting Tools (ILT) from 8” to 102” are used for the safe lifting and upending of tubular piles for insertion into the seabed. ILTs can be inserted either horizontally, using the centre of gravity bracket as a lifting arm, or lowered vertically into the pile. The ILT is then hydraulically actuated in order to set the locks, gripping the pile internally. The ILT is then raised using its lifting eye at the end of the central shaft. The pile can then be lowered into a socket on the seabed. The ILT is unset and retracted in order for the pile to be driven into the seabed by a hydraulic hammer.
ILT bodies can be resized using various upsizing kits allowing one tool to cover a wide range of pile sizes, each resizing setup can handle a 6” ID variation – covering all pile wall thicknesses with just one setup. Tool resizing is fast and simple due to the transport and handling frame with in-built lifting apparatus, allowing easy component change-out. The ILTs benefit from optional sealing units which provide suction and pressurisation functionality to greatly improve the handling of tubular piles and aid with pile removal.
Specification 48” to 90”
- Design Code: DNV Standard for Certification No. 2.22 Lifting Appliances
- SWL Vertical: 600T
- Proof Load Test: 800T
- Horizontal Pile Upending: Capable of upending a 220T pile from horizontal position
- Maximum Water Depth: 3500m
- Maximum Pile True Batter (600T lift): 11.77 deg (from vertical)
- Operation: Via umblical to 200m / 200-3500m with optional ROV operated package
- Possible Upgrade with Sealing Module: To aid suction assisted pile installation or pressure assisted pile removal
- Resizing and transport frame: In-built lifting apparatus for fast component-changeout and resizing
Strap Clamp – Repair, Hot Tapping or Encapsulation
STATS patented strap clamp provides a localised seal on a pipe surface. These clamps can be used for either pipeline repair or hot tapping operations. Lightweight in design they are simple to install and offer a robust isolation for localised sealing.
Sealing a localised area of the pipe reduces the sealing area hence the loads which need to be restrained. Due to this these clamps are much lighter and easier to handle than a traditional repair clamp which encapsulates the whole circumference of the pipe.
The localised sealing area is provided by a circular ‘D’ seal, mounted in a profiled groove which confirms to the pipe OD. The size of the repair which can be accommodated with this design can vary but must be small in relation to the pipe diameter, less than 25%.
The clamp is installed by assembling the strap around the pipe and connecting the two elements together. Once connected, the strap can be orientated to provide easy access for assembling the seal housing.
The clamp can then be located to the correct position and the strap bolt tightened. The elastomeric seal on the pipe can accommodate a poor surface finish on the pipe OD, however coatings must be fully removed and any deep gouges must not impinge on the seal contact area.
The strap bolts do not require a high torque as they are only required to provide the initial seal. Once pressure is applied to the seal housing, the pipe seal will become energised by the differential area acting across the cartridge. This is an important feature on thin pipe wall, where the pipe would deflect with preload on the strap bolts.
- Lightweight strap clamp for localised repair or intervention
- Self-energised sealing against pipe
- Simple and fast to install
- Low profile design allows installation in restricted space
- Seal housing can be configured for Repair (Blind); Hot Tap (Flanged); or Encapsulation (Capped) formats
- Available for low and high pressure applications
- Modular construction allows cross utilisation of components for different pipe geometries
- Seal material provided to suit application (NBR, HNBR, Viton, HPU)
- NACE compliant carbon steel as standard, other materials available upon request
- Available in single or dual seal arrangement
PIN-HOLE LEAK REPAIR CLAMP
Pin-Hole Leak Repair Clamp
Pin-Hole Leak Repair Clamps have been developed for process piping repair in oil and gas process facilities. Installation can be undertaken with minimal disruption to the pipework or operation of the system to which they are fitted.
Designed for simple installation, Pin-Hole Leak Repair Clamps are designed to provide a rapid and versatile solution for localised leak points.
- All pipe range sizes 2” upwards
- Pressure range: up to 153 Bar (900lbs)
- Maximum pin-hole size up to 12mm
- No preparation required
- Can be fitted onto live leak
- Simple to install
- Xylan coating provides excellent corrosion resistance