Zupt, LLC offers many innovative survey and positioning products to increase productivity for marine applications including tools for marine construction, dynamic positioning and deepwater drilling.
Many offshore survey and positioning operations are on the critical path of very expensive assets. Zupt, LLC focuses on changing the way we complete some of these precise operations through the introduction of next generation survey tools available for all marine applications.
Metrology – the precise measurement of subsea connector (hub) locations to provide the data for the manufacture of an inter-connecting jumper. C-PINS has completed many offshore metrology surveys saving up to 70% of the time taken for such surveys.
Deep water precise positioning has, for years, required the expensive deployment of a long baseline (LBL) acoustic positioning system. Today through the combination of inertial navigation system with surface vessel referenced ultra short baseline (USBL) the time taken for the deployment and calibration of an LBL array can be saved for many “relative” positioning tasks by using our USBL smoothing solution. If the requirement is for precise “absolute” subsea positioning – our “real time calibration” option for the USBL smoothing system can maintain absolute positioning accuracy and quality metrics that stretch USBL to deep water survey operations that have required LBL in the past.
Should LBL type capabilities still be required at the seabed then the “Sparse LBL” version of C-PINS reduces the need for large LBL arrays. With either one or two simple acoustic transponders deployed at the work site the combination of inertial and acoustic line of position allows for very reliable and precise positioning. The vessel spread time consumed for such tasks as buoy placement for well installation, suction pile marking and mat installation is significantly reduced saving overall project costs.
Increases in the reliability of position reference sensors for dynamic positioning have been sought for many years. Stand alone satellite delivered DGPS systems are a mainstay of this industry – but scintillation, multipath and total signal loss due to vessel components masking GPS antennas have caused DGPS outages and unplanned DP incidents. Acoustic positioning systems have also taken the place of taut wire in deeper water as the secondary (or primary in some cases) position reference sensors.
Acoustic positioning systems – SBL, LUSBL and USBL have for years provided reliable input into the DP desks when used within their limitations. Commercial pressures drive the operations of these systems into water depths and applications beyond the original design. Position jitter from USBL system in deep water cause the DP desk to reject the system. The cost to deploy an LBL array when working on locations for short periods (workover, marine construction DP vessels) as well as slow LBL update rates drive reliance on DGPS as the primary position reference sensor. Class requirements state that 3 independent position reference sensors operating from 2 different principals should be available on all DP 2 and DP 3 class vessels. Combining these conventional position reference sensors with inertial navigation systems significantly improves the reliability of the overall solution – as well as providing a higher update rate. D-PINS is a very capable implementation of such a solution, the system provides very precise heading, pitch
and roll data. The system being tightly coupled to the DGPS solution can operate without any impact with just a single range to a satellite. The same applies to acoustic integration. A simple range to a beacon once every 30 seconds maintains the position solution into the DP desks. In conventional configurations either of these situations would be the cause of a DP incident – shutting down the work. In the drilling case this would instigate an unplanned disconnect – a very costly action.
One of the oldest reference sensors used in deep water drilling, both moored and dynamically positioned, has been a Riser Angle sensor. The dynamically positioned vessels will have an electrically connected (ERA) riser angle sensor. The moored drilling vessels will combine the riser angle sensor within the short baseline (SBL) or ultra short baseline (USBL) acoustic positioning system deployed on the vessel. The ERA sensors deployed within the subsea mux control systems have had a reputation for not being reliable or accurate. Simple inclination sensors have been used that degrade in the presence of vibration. These sensors do not have the resolution required to view incremental changes in vessel position deep water.
The installation, maintenance and calibration has not been viewed from an operational perspective – they are just there and in many cases are not used.
The Zupt high resolution ERA solves these problems by using high resolution, state of the art inertial sensors with high update rates. Stack heading is sensed to ensure differential riser angle across the flex joint is known with reference to either vessel North or true North.
Zupt has a wide range of sensors and capabilities for the offshore market, all developed to fundamentally improve productivity of operations saving vessel time and increasing the reliability of these operations.
Why change what is currently working offshore?
Nothing has changed for the past 20 years (apart from colored graphics at the surface)!
Most current subsea marine construction surveys still use conventional acoustic positioning techniques. We are beginning to see some inclusion of inertial instruments within some of the applications discussed below but most operations use techniques that are basically the same as those used 20 years ago. These conventional acoustic positioning systems provide the required positioning accuracy, but consume far too much operational time – they cost too much in Boat and ROV time.
Deepwater marine construction survey methodologies have reached a plateau. The repeatability of such operations observed in recent years highlights the mature nature of the technology and procedures. Mistakes are still made and budgets are still impacted by procedural, equipment and operational failures. Few can argue about the industries ability to complete deepwater marine construction survey tasks – the problem is not the quality, or the capability to complete the task – but the cost to the overall project.
Zupt’s capabilities will significantly reduce vessel and ROV time consumed to provide precise relative and absolute deepwater positioning for many marine construction activities.
Our tools bring major cost savings in many marine construction applications. A few examples being:
Metrology – providing repeatable, reliable positioning data while consuming minimal ROV/spread time. A local, relative positioning problem well suited to our aided inertial solution.
Local field development positioning – 300m x 300m subsea infrastructure relative installation – Zupt significantly reduces the operational time currently consumed to deploy and calibrate large LBL arrays while we also reduce the LBL beacon count significantly.
Wide area deepwater absolute positioning – 3,000m x 3,000m field wide control with significantly reduced acoustic observation sets. For these operations we reduce Vessel/ROV spread time consumed due to less hardware deployed on the seabed. Such an application is deepwater permanent suction mooring installations.
Deepwater pipeline “as built” survey – improving the survey deliverable from USBL systems by aiding with an inertial observation set – no need for LBL.
Increases in update rate and quality of positioning and attitude for such ROV based tasks as bathymetry (multibeam), visualization and automation.
Significant cost savings can be achieved through the use of our technology. If we look at the example of a single multi-well field development the following are conservative estimates of costs savings:
Some very simple assumptions – Near field/Far field array installations for local subsea field installations in a large field development program. Multiple frame set, array installation and calibration at 4 locations:
5 far field transponders
6 near field transponders
2.8 boat/ROV spread days per location $65K/day complete spread rate
4 locations 4(2.8×65) = $728K
Using Zupt’s tools and services:
3 near field transponders
1.3 boat/ROV spread days per location $65K/day complete spread rate
4 locations 4(1.3×65) = $338K
A very conservative estimate of savings = $390K on a single job.
High precision and superior quality in deep water
Zupt brings both the operational knowledge and technical expertise to allow state of the art technical solutions to significantly reduce the operational time consumed for these tasks.
An example of some subsea positioning tasks and the accuracy required are:
Metrology (Jumper and spool piece) 5-10 cms relative
Pipeline Cut to Length 1-2 meter – absolute
Batch Wellhead Positioning 30 cms-relative
Seabed – General Positioning 1 – 3 meters-absolute
The water depths for these operations vary from shallow water shelf operations (200m) to deep frontier locations (4000m).
Zupt’s capabilities in this market are primarily ROV based and as such provide the capability to measure distances and angles for many subsea marine construction tasks.
This subsea aided inertial product provides very precise, high update rate real time and post processed position, heading and attitude data. These capabilities have been designed and constructed to survive the offshore environment and work in the “real world” of daily operations – such as limited bandwidth ROV communications.
When precise or reliable dynamic positioning is critical, our inertial navigation systems coupled with DGPS (Differential GPS) and/or Acoustic technologies such as USBL (Ultra Short Base Line) offers superior accuracy and reliability for your offshore operations. Our Dynamic Position reference sensor D-PINS is the most cost effective method of adding redundancy to your existing DP systems. D-PINS offers minutes of accurate positioning during outages which greatly reduces cost and risk associated with these conventional reference sensor system outages. Our inertial navigation solution can be easily integrated with any DP desk and system configuration. Using the D-PINS inertial navigation system greatly reduces costs associated with rig and construction vessel time while adding reliability.
Reliable Position Reference Sensors
The most reliable deep water sensors for dynamic positioning are DGPS, Acoustic and Inertial Navigation. Both DGPS and Acoustic technologies are reliable but do have their drawbacks such as signal degradation due to weather or noise interference. While Inertial Navigation cannot be used alone, used in tandem with DGPS and/or Acoustic it not only offers reliability but improved accuracy including with heading and attitude.
USBL Smoothing for Dynamic Positioning
Repeatability in acoustic navigation systems is key to proper dynamic positioning. By using the D-PINS system you dramatically increase that repeatability of your existing USBL solution. Our system intelligently combines the noisy USBL data with very high update rate, low noise inertial data.
Offshore Drilling vessels depend on the reliability of their Dynamic Positioning Systems (DP). At the same time, cost is always an issue. By easily combining our Inertial Navigation System with your existing DP Position Reference Systems you not only reduce operational costs but also increase accuracy and reliability of your system. The combined effect is safer and more environmentally friendly system that greatly reduces the cost of your offshore drilling operations.
Our D-PINSTM System merges our Inertial Navigation Data with standard DGPS and Acoustic telegrams providing an accurate position telegram to an open slot on the DP desk.
Our system easily integrates with your DGPS and Acoustic Systems to provide extremely accurate, high update rate position awareness.
If you are currently deploying LBL arrays using our system reduces the need to deploy 5 LBL transponders to 1-2 transponders. This alone reduces time and cost for deployment.
Advantages to D-PINSTM :
- Increased Reliability
- Improved Accuracy
- Higher update rate
- Reduced Operational costs
- Redundancy for existing systems that can fail
- Decreased Array Deployment Costs
Dynamic Positioning – Far higher positioning reliability through the intelligent use of multiple observation sources.
Give your DPO’s the chance to solve problems before they become career-making decisions. The intelligent integration of already existing observations gives you many more options that you currently have to fulfill contractual and “Class” requirements.