Gas Lift Challenges
Little has changed over the past decades to prepare the industry for the gas lift challenges being faced today. These include:
- Deeper, longer, and more highly deviated wells.
- Higher pressures / temperatures and more corrosive / scaly environments
- Increased focus on well integrity
- Increased recognition of production inefficiencies due to multipointing
- The need to retrofit new or upgrade existing gas lift systems without recompletion
- The need to reduce the number of well interventions
To address these challenges, PTC has developed the next generation of gas lift technologies, which are now widely used by most OPCOs worldwide.
The increased reliability, flexibility and longevity these technologies offer, has also led to the development of a unique life of field approach to gas lift system design.
Gas Lift Valve Technology
The Gas Lift Valve (GLV) has historically been the component most prone to malfunction and failure in a gas lift system. Scale, erosion, chattering, and unloading valve bellows fatigue or dome charge valve leakage, are widely reported causes.
PTC has designed, qualified and incorporated many revolutionary features in our Lift-family GLVs that have greatly improved reliability and operational efficiency. These include:
- Proprietary barrier certified orifice and back-check valve system, which is less prone to chattering, and erosive wear of the metal to metal sealing surfaces
- Unique low load rate / long stem travel dual operating bellows type Injection Pressure Operated (IPO) valves. These valves can be reliably used as operating valves, eliminating the need for interventions to change lift gas injection depth. The bellows are rated to 12 500 psi and have been tested to 50 000 full open/close cycles.
- Shear activated GLVs that allow operators to run multiple valves (unloading and orifice) in the same completion string and shear them open in one operation.
Anti-scale valve design providing longevity in scaly environments.
Side Pocket Mandrel Technology
PTC's NexLiftTM Series of SPMs has the following differentiation features:
- Zero (NexLift SITM) or only 2 circumferential TIG robot welds (NexLift ROTM), as opposed to 4 or 5 manually applied MIG welds in competitor mandrels, which reduces:
- The likelihood of weld related failures
- The number of chamfers and grooves where wireline tools may hang up.
- Zero heat treatment (NexLift SITM) or state of the art local heat treatment processes (NexLift ROTM) are used which eliminate:
- the tendency for the mandrel to warp during full body post weld heat treatment, that requires "final straightening" involving the application of stresses that may exceed the material yield
- Full length tool discriminator, which ensures:
- Perfect valve/pocket alignment before valve insertion/retrieval to/from the pocket, thus reducing the likelihood for mis-runs and packing damage.
- The likelihood of latch damage due to collisions during subsequent coil tubing intervention ops is significantly reduced
- By-pass slots for cables and control lines have hinged keeper plates, which eliminates:
- Loose parts that can be dropped in the well
NexLift SITM and NexLift SI-BTM
PTC’s NexLift SITM and NexLift SI-BTM mandrels are the only true single-piece, unwelded Side Pocket Mandrels in the industry. Their unique design provides unrivalled structural integrity, while reducing issues related to the installation and retrieval of valves. As no welding is used during the manufacturing process, NexLift SITM and NexLift SI-BTM mandrels can be manufactured from alloys that have traditionally not been used due to poor weldability, reducing the costs of the SPMs while providing a superior product. PTC’s NexLift SI-BTM mandrel also protects the production casing from potentially harmful fluids and pressure.
PTC’s NexLift ROTM Side Pocket Mandrel is the first mandrel ever to be designed with less than 3 circumferential welds. PTC's NexLift ROTM mandrels have been qualified in accordance with API's 19G1 V1 requirements.
GoLiftTM Retrofit Gas Lift Straddles
PTC’s GoLiftTM through tubing gas lift straddle system offers a cost-effective alternative to workovers where there is a need to retrofit new or upgrade existing gas lift or chemical injection systems, without compromising well integrity.
Life of Field Gas Lift Design
Traditionally decisions regarding the optimum number and setting depths of valves in gas lifted wells have been made considering only a small number of operating scenarios. As a result, wells often do not perform as expected.
PTC’s unique life of field design process considers a wider range of life-cycle operating conditions and data uncertainties. It therefore provides a more robust design to ensure maximum production, and reliability over the life of the well.