Streamer steering, enabled by DigiFINand Orca, is critical to ION’s Intelligent Acquisition approach to simplify and automate operations. By integrating our technology into a seamless system, higher resolution data can be acquired more efficiently and safely.
Real-time acquisition optimization
ION optimized a 3D program last summer off the coast of Australia using steerable streamer technology. Despite challenging currents, DigiFIN and Orca achieved unprecedented spread control among 10 streamers and counteracted environmental variables, such as ocean currents, that cause streamers to feather and form irregular shapes. Applying the following techniques resulted in minimal infill, safe, efficient operations, and finely sampled seismic data.
How it works
Deployed throughout the spread, DigiFIN lateral control devices are directed by Orca command and control software to steer the cables. Orca defines the wing angle for each DigiFIN device to achieve the cable direction, separation, and intensity desired. Combined, DigiFIN and Orca fine tune the positioning and control of the spread in dynamic sea conditions.
Productivity benefits
Streamer steering improves productivity by reducing infill and minimizing time spent on offline operations. Infill may be required if all bins were not acquired with all offsets during the first pass. Accounting for 30% or more of survey costs, re-shoots are time-consuming for service providers and costly to oil companies.
DigiFIN adjusts or induces a feather angle in the spread to maximize coverage. By steering the vessel to perfectly align near offsets and steering the cables to feather match far offsets, outstanding coverage eliminated unnecessary overlap and elective infill.
Deploying and retrieving cables is time and labor intensive, requiring up to a week using traditional methods. By driving streamers apart during deployment, crews can slot streamers faster and control longer streamers better, mitigating entanglement risk. In addition, crews can deploy and retrieve multiple cables simultaneously instead of one at a time.
DigiFIN enables faster turns by steering streamers outward and straightening them more quickly for reduced run-in time.
Imaging benefits
Steerable streamer benefits far exceed operational efficiencies. Tighter, more uniform cross-line separation enables more finely sampled data. The increased control improves 4D repeatability by more closely aligning source and receiver positions to pre-plots or prior surveys.
DigiFIN improves image quality by maintaining close, even cable separation for denser spatial sampling and eliminating propeller trousering that can create holes or sparse bins.
Safety benefits
An increasing number of surveys are acquired on existing fields to maximize production, which often necessitates close-passes near rigs and other hazards. DigiFIN increases spread control and maintains a constant, user-defined cross-line separation to mitigate both the risk of obstructions and cable entanglement.
DigiFIN enables operators to steer more closely and safely around obstructions with better coverage(right) than conventional methods (left).
Advancing streamer steering
ION is advancing streamer steering capabilities to further mitigate risks, reduce costs, and enhance image quality. As the cost and complexity of towed streamer surveys rise, streamer steering will be an invaluable asset to marine acquisition.
