Isolation & Intervention
Isolation of pipelines and pipework systems is a key requirement for the maintenance and modification of oil, gas and petrochemical infrastructure. STATS Group has access to a wide range of pipeline isolation techniques and offers a consultation service to assist operators in assessing the optimum solution for their pipeline isolation challenges. Our comprehensive range of products and services provide the highest practical pipeline isolation integrity for a vast variety of applications.
STATS supply isolation devices from ¾ inch to 48 inches that are compliant with 1D to 5D bends. Our extensive product range allows for isolations to be undertaken safely and efficiently on ambient or pressurised systems. This product range also allows for isolations to be undertaken where full bore access is not available. STATS have designed and manufactured a number of world-beating products, which have led major operators to reassess how they manage isolation and intervention projects.
- Tecno Plug™ – Non-Intrusive Inline Isolation
The Tecno Plug™ provides fail-safe double block and bleed isolation of high pressure pipelines while the system remains live and at operating pressure. Dual seals provide a zero-energy zone to enable maintenance work to be carried out safely and efficiently. Piggable isolation tools require no welding or cutting into live lines, leaving no residual fittings or hardware on the pipeline.
- BISEP™ – Hot Tapping and Plugging
Hot Tapping and Plugging can be achieved using STATS patented BISEP™. The fail-safe double block and bleed isolation is deployed through a single full bore hot tap penetration, without the need for additional bleed or vent ports. The BISEP™ offers significant safety advantages over traditional line stop technology, the hydraulically activated dual seals provide leak-tight isolation of live, pressurised pipelines.
- BI-STOP™ – Small Bore Hot Tapping and Plugging
A unique process to address problems with small bore pipework that have absent or limited isolation facilities. This innovative solution enables small bore pipework and branches to be isolated, cut and terminated with a full bore valve whilst the system remains live.
DNV GL Type Approval
STATS Tecno Plug™ and BISEP™ are fully certified by DNV GL to verify that the design criteria satisfies the requirements for Pipeline Isolation Plugs to provide dual seal and isolation in accordance with Offshore Standards; DNV-OS-F101 (Submarine Pipeline Systems) and recommended Practices; DNV-RP-F113 (Subsea Pipeline Repair) and in compliance with the following code; ASME BPVC Section VIII, Division 2.
STATS have an extensive track record of providing temporary pressurised isolation of onshore and subsea pipelines in a range of sizes. Isolation operations have been undertaken in most pipeline mediums including, gas, crude oil, liquid CO2 and condensate.
Non-Intrusive Inline Isolation
Tecno Plug™ – Non-Intrusive Inline Isolation
The Tecno Plug™ provides fail-safe double block and bleed isolation of pressurised pipelines while the system remains live and at operating pressure. Dual seals provide a zero-energy zone to enable maintenance work on pressurised systems to be carried out safely and efficiently. Piggable isolation tools require no welding or cutting into live lines, leaving no residual fittings or hardware on the pipeline.
The dual seal configuration of the Tecno Plug™ provides an annulus void which can be pressure tested to verify both seals are leak-tight before maintenance work is carried out. Both seals are leak tested at 110% of the maximum potential isolation pressure. Once the seal integrity has been proved the annulus is then vented to ambient to create a zero-energy zone, providing effective double block and bleed isolation. The large section elastomer seals are highly compatible with poor pipe surfaces and are engineered to suit corrosion or ovality issues ensuring a leak-tight seal even in ageing assets. A through-port is provided for downstream pressure monitoring or pressure application as required.
The Tecno Plug™ fail-safe design uses differential pressure acting on the tool to energise the locks and seals, this is referred to as self-energisation. When the isolation plug is self-energised the isolation is maintained independent of the control system, it is however backed up by the hydraulic control system which maintains the isolation when the differential pressure is below the self-energisation threshold. Once the Tecno Plug™ is activated the hydraulic circuits are locked in by pilot operated check valves and manual isolation valves (tether controlled) or fail-safe solenoid valves (remote controlled). The check valve pilot lines can be separate lines controlled independently if required. The Taper lock-ring provides twice the required lock contact area giving 100% contingency. In the event that the hydraulic control system is compromised, the tool actuation mechanism will unset when differential pressure is equalised. This feature ensures pipeline integrity is maintained and the Tecno Plug™ is always recoverable upon job completion.
The remotely operated Tecno Plug™ system is a piggable, remote controlled, tetherless isolation tool. The remote control system provides a high degree of flexibility and eliminates the need for tethers or specially modified pig-trap doors. Through-wall communication is achieved using an extremely low frequency (ELF) radio control system for reliable tracking and accurate positioning of the Tecno Plug™. An onboard hydraulic power pack provides the necessary actuation and control functions for the tool. The remote control module provides a robust system for safety critical activities and has undertaken a rigorous validation programme with ATEX rating to Ex P2 II 3 GT3. The external communication system is housed in an ATEX rated enclosure EE xd IIB T5.
Pigging Bypass Technology – Unpiggable Pipelines
STATS have developed a patented pigging bypass system for our isolation plugs which allows two plugs to be pigged towards a blind centre. The technology was developed to facilitate the pipeline repair of unpiggable defects. This system allows a section of pipeline to be isolated where full bore pipeline access is unavailable due to a defect such as a pipeline buckle or dent. Each isolation plug is pigged from either end of the pipeline towards the defect to isolate the section and allow repair or replacement.
- Piggable isolation tools require no welding or cutting into live lines, leaving no residual fittings or hardware on the pipeline
- De-commissioning (bleeding down) and re-commissioning (refilling and re-pressurising) of pipelines minimised or eliminated, saving time and reducing costs
- Production continued during pipeline maintenance or modifications
- No flaring of gas or displacement of pipeline inventory
- No emissions of gas or hydrocarbon vapour to the atmosphere during blow down
- No danger of accidentally flooding offshore pipelines during construction
- No need to dispose of hydrates, chemicals and contaminated water
- Isolates short sections of pipeline anywhere in the pipeline system
- Emergency preparedness and operational readiness
Key Features Tecno Plug™
- Size range: 3” – 48”
- Pressure range: up to 600 bar / 8700 psi
- DNV GL Type Approval in accordance with; DNV-OS-F101 (Submarine Pipeline Systems) and recommended Practices; DNV-RP-F113 (Subsea Pipeline Repair)
- Available as 3D bend compliant as standard with 1.5D on request
- Robust compact design, enables Tecno Plug™ to be set in short sections of pipeline. In many instances production can be continued during pipeline maintenance or modifications activities
- Twin compression elastomer seals are highly effective even in pipelines with corrosion and ovality issues
- High integrity isolation, taper lock-ring provides twice the required lock contact area i.e. 100% contingency
- Annulus bleed between seals allows pressure to be vented to ambient creating a zero-energy zone providing true double block and bleed isolation
- Fail-safe design feature; lock & seals energised by differential pressure; referred to as self-energisation
Self-energisation feature maintains safe isolation while differential pressure exists across the plug
- Hydraulic system override releases the plug setting mechanism when pressure is equalised (Fail-safe passive unset feature)
- Both seals fully energised by pressure – rubber pressure 1.1 – 1.4 times greater than pipeline pressure
- Reverse pressure can be applied across the isolation plug to facilitate system leak testing
- Outboard pressure monitoring options
Key Features Remote Tecno Plug™
- Size range: 10” – 48”
- Pressure range: standard remote control module housing is rated for 200 bar (2900 psi) external pressure
- DNV GL Type Approval in accordance with; DNV-OS-F101 (Submarine Pipeline Systems) and recommended Practices; DNV-RP-F113 (Subsea Pipeline Repair)
- The remote control module provides a robust system for safety critical activities and has undertaken a rigorous validation programme with ATEX rating to Ex P2 II 3 GT3
- The external communication system is housed in an ATEX rated enclosure EE xd IIB T5
- Through-wall communication is achieved using an extremely low frequency (ELF) radio control system for reliable tracking and accurate positioning
- Subsea communication via acoustic link (3000m depth rating)
- Remote Tecno Plug™ does not use lithium batteries negating the need for Emergency Response Procedures for the transportation / use of extremely hazardous materials
- Pipeline valve replacement / repair
- Riser replacement / repair
- Mid-line pipeline repair / tie-in
- Platform abandonment and bypass
- Pipeline diversion
Hot Tapping and Plugging
BISEP™ – Hot Tapping and Plugging
Hot Tapping and Plugging can be achieved using the DNV GL type approved BISEP™. STATS patented BISEP™ provides fail-safe double block and bleed isolation deployed through a single full bore hot tap penetration, without the need for additional bleed or vent ports.
The BISEP™ offers significant safety advantages over traditional line stop technology, the hydraulically activated dual seals provide leak-tight isolation of live, pressurised pipelines.
This high integrity isolation is provided by a spherical dual seal plug which is deployed from a pressure competent launcher through an isolation valve and rotated towards the flow of pressure to be isolated. The seals are activated by a hydraulic cylinder inside the plug which compresses the seals, the resultant radial expansion pushes the seals out against the pipe bore. Further application of hydraulic pressure generates a rubber pressure in the seal elements which allows the annulus void between the seals to be pressure tested. Each seal is independently tested with full pipeline pressure in the correct direction to verify leak-tight isolation. The seal annulus void is vented to ambient through the BISEP™ plugging head to provide a zero-energy zone and provides constant monitoring capabilities to prove the seal integrity before and during maintenance, repair, or modification activities.
Line pressure acting against the tool pressure head maintains seal pressure creating a fail-safe feature providing actuation independent of the hydraulic system. The ejection load resistance is provided by the BISEP™ deployment head.
Dual BISEPs™ can be used to provide mid-line isolation of pipeline sections and the introduction of a bypass line allows sectional isolation to take place without the need to shut down the entire system or affect production.
Once the BISEP™ is deployed and set in position the pipeline repair or maintenance activities can take place safely and efficiently.
- Hot Tap and Plugging Case Study
World First: Leak-tight double block and bleed isolation on high pressure CO2 pipelines
Reinstatement Pressure Testing
The BISEP™ is designed to resist back pressure so can be used as a test boundary for the reinstatement test. This back pressure is however limited, as the pressure must be retained by the hydraulic set pressure. The BISEP™ is designed to take 50% of the design pressure as a reverse pressure differential. This is a differential pressure and allows a test pressure 50% higher than the isolated pipeline pressure to be applied to the reinstated pipework as a pressure test, prior to removing the BISEP™ isolation.
Hot Tap and Plugging Applications
- Pipeline / launcher valve installation or replacement.
- Pipeline / riser repair, replacement or decommissioning.
- Pipeline / pipework re-routing.
- Mid-line pipeline repair due to corrosion or mechanical impact.
- Isolate pressure vessels.
- Water or gas injection line isolation.
- Isolation of pipeline end manifolds, pipeline end terminals, subsea manifolds or skids for repair, upgrade or replacement.
Hot Tap and Plugging Operator Benefits
- Fully verified Double Block and Bleed isolation through a single hot tap point:
- Leak-tight isolation dramatically increases safety over traditional line stop technology.
- Single operation significantly reduces timescales and costs. (Single fitting, welding, inspection, scaffolding, crane and excavation costs).
- Single fitting allows installation on short sections of pipework.
- BISEP™ technology complies with operator double block and bleed requirements.
- Minimal production disruption on interconnected pipeline networks during valve repairs / tie-ins.
BISEP™ Key Features
- Dual seal annulus void proves and monitors the seal integrity before and during any intervention work.
- Isolation integrity continuously monitored through annulus void, hydraulic set circuit and body vents.
- Seal annulus void provides a Zero-Energy Zone.
- Design provides axial restraint through bearing on dual clevis plates (no single point failure).
- Dual compression seals are more compliant and have a far higher success rate than traditional cup seals particularly in pitted pipework.
- Self-Energisation of seals maintains isolation integrity independent of hydraulic control circuit.
- No need for additional taps for bleed / vent ports.
- Can accommodate reinstatement pressure test against rear of BISEP™.
- BISEP™ isolation installed upstream of fitting, maintaining fitting in safe zone during workscope.
- BISEP™ launcher ported to facilitate venting, purging and flushing of isolated section.
- Can be deployed through conventional equal tee / clamp / branch.
- Size range: 3 ”– 48”
- For sizes 2” and below see STATS BI-STOP™ range
- Pressure range: up to 153 bar
- DNV GL Type Approval
- Design allows for deployment into flow conditions (Engineering Assessment Required)
STATS can supply welded split tee fittings or temporary mechanical tie-in clamps along with STATS patented dual seal slab valves and hot tapping services. Once the BISEP™ is recovered, STATS can provide a completion plug to provide permanent isolation to the branch off-take and enable the removal of the slab valve allowing a blind flange to be fitted.
Small Bore Hot Tapping and Plugging
BI-STOP™ – Small Bore Hot Tapping and Plugging
Small bore intervention and isolation service provides a unique process that has been developed to address problems with small bore pipework that have absent or limited isolation facilities. The process enables small bore pipework and branches to be isolated, cut and terminated with a full bore valve whilst the system remains live. This patent pending product range has been specifically designed for small bore pipework, nominal size ranges from ¾” to 3” with a pressure range of class 150# (20 bar working).
For sizes 4” and above see STATS BISEP™ range.
- Eliminates the need for system shutdown.
- Innovative equipment design addresses all the destruct and construct requirements including proof testing.
- Provides a cost effective means of installing additional system isolation valves or tie-in branches.
- Provides a cost effective method of terminating dead leg branches or destructing redundant pipework and equipment.
- Allows redundant pipework and systems to be safely decommissioned without production outage.
- Suitable for permanent or temporary tie-in, pipework re-routing and spool section repair.
- Unplanned outage and maintenance costs eliminated or reduced.
- The process enables small bore pipework and branches to be isolated, cut and terminated with a system specified full bore valve whilst the system remains live.
Hot Tapping Services
Hot Tapping Services
STATS Hot Tapping services allow a branch connection to be made into piping or vessels while the system remains live and under working pressure, allowing continuous system operation and avoiding unplanned shutdowns and service interruptions. STATS provide a safe and cost effective solution to allow efficient tie-ins for repair or modification purposes while under full operating conditions, therefore reducing plant downtime.
STATS provide a full range of ‘industry best in class’ equipment and can provide a turnkey packaged approach from clamp or tee installation through to isolation of line content, inclusive of slab valve and completion flange provision. STATS will undertake system engineering analysis and project engineering as part of this service. A comprehensive service package is available to support Hot Tapping operations from ½” to 48”.
Once Hot Tapping is complete STATS can provide a verified double block and bleed isolation through a single penetration. The BISEP™ with dual compression seals and annular bleed provides a high integrity dual seal isolation allowing repair or modification work to safely take place. This single entry point isolation technique significantly reduces operator costs and timescales.
- Continuous system operation, shutdown and service interruptions avoided
- Hot Taps performed on a variety of piping and vessel materials and mediums
- No pipe content released to the atmosphere
- No cutting, realignment and re-welding of pipeline sections
- Planning and coordination costs reduced
- Increased worker safety
Mechanical Tie-In Clamps facilitate the connection of new branch pipework to existing infrastructure without the requirement for welding. Tie-In Clamps are routinely used to provide a flanged off-take to enable hot or cold tapping into an existing pipe.
The system components are compatible with a wide range of fluid types and flow conditions and are designed for ease of installation with minimal disruption to the pipework or system to which they are fitted.
- Size range: standard pipe sizes ¾” – 46”, with branch diameter to suit application.
- Pressure range: up to ASME 900#.
- Dual seal design with annulus test facility.
- Structural locks / grout injection to suit application.