At SES, our goal is to fill your marine seismic needs quickly and effectively, so you can minimize downtime for your operations and maximize production. We’re here to help with all things related to your source. Repair. Design. Support. Or simply getting the right part in your hands faster. our Marine Technical Support delivers first-rate service time after time.

• Source Deployment Design, Support & Audits
• On-site Streamer Lead-In and Source Umbilical Terminations
• Optical and Electrical Terminations
• Equipment Rental & Leasing
• Experienced Project Managers Specializing in Back Deck Source and Handling Rig Up

OVERVIEW

In marine seismic surveying, relatively low energy waves are mechanically generated and directed into the water. Some of the energy is reflected back to the surface from the different layers below the surface. The returning waves are detected with sensitive measuring devices that accurately record the strength of the wave and the time it has taken to travel through the various layers and back to the surface (Fig.1.).

Most surveys incorporate 3D surveying which is a much more complex and accurate method of seismic surveying, and uses much more sophisticated equipment than 2D surveying.

Since much effort will be put into the acquisition, processing and interpretation of the survey, it is very important that it is designed to achieve the survey objectives. The result of the detailed planning will be a map defining the survey boundaries and the direction of the survey lines. Specific acquisition parameters such as energy source, firing and receiver station intervals, together with the seismic listening time, will also be defined. In 3D surveying, groups of sail lines (or swathes) are acquired with the same orientation (Fig. 2).

A 3D survey is therefore much more efficient in that many times more data is generated than for 2D. A small 3D survey size is of the order of 300 square kilometres or 1000 sail line kilometres or 12000 sub-surface 2D kilometres. 3D surveys are typically acquired with a racetrack pattern being employed, to allow adjacent sail lines to be recorded in the same direction (swathe), while reducing the time necessary to turn the vessel in the opposite direction. This increases the efficiency of acquiring the data and minimizes processing discontinuities, which could adversely affect the interpretation of the data (Fig. 3.).

FIG. 1. During marine seismic surveys, low energy waves are mechanically generated and directed into the water and then some of the energy is reflected back to the surface.	FIG. 2. Typically, marine 3D surveys are acquired with a racetrack pattern being employed, to allow adjacent sail lines to be recorded in the same direction (swathe),	FIG. 3. Specialized gear enables the multiple streamers and source arrays to be positioned accurately behind the seismic vessel. The airgun system and the towing equipment are maintained by the seismic crew.

The SEISMIC SOURCE

Although there are now three types of seismic source, airguns, waterguns and vibrators, that can be utilized, almost all surveys conducted world-wide use airguns. The airgun, comprises two high pressure air chambers; an upper control chamber and a discharge chamber. High pressure air, at typically 2000 to 2500 psi, is supplied to the upper control chamber from the compressor onboard the seismic vessel via an air hose and bleeds into the lower firing chamber through an orifice in the shank of the shuttle. The airgun is actuated by sending an electrical pulse to the solenoid valve which opens, allowing high pressure air to flow to the underside of the triggering piston. The high pressure air in the lower (firing) chamber is discharged into the surrounding water through the airgun ports. The air from these ports forms a bubble, which oscillates according to the operating pressure, the depth of operation, the temperature and the volume of air vented into the water. The shuttle is forced back down to its original position by the high-pressure air in the control chamber, so that once the discharge chamber is fully charged with high-pressure air, the airgun can be fired again. The opening of the shuttle is very rapid, taking only a few milliseconds, which allows the high-pressure air to be discharged very rapidly. Total energy source volumes vary from survey to survey and are designed to provide sufficient seismic energy to illuminate the geological objective of the survey, whilst minimising environmental disturbance.

At SES, we offer a range of services that helps make your operation run more efficiently. Field service repairs. Air system and source audits. Back deck handling gear design and integration. Hose bundle termination. Bolting on applications, such as oilers and dryers. And everything in between.

On-site Air Source Systems Service, Repair & Support Certified Experts in High-Pressure Air Source Systems Source Deployment Design, Support and Audits On-site Streamer Lead-In & Source Umbilical Terminations Optical and Electrical Terminations Source Float Systems Equipment Rental and Leasing Experienced Project Managers Specializing in Back Deck Source and Handling Rig Up

At SES, our entire team, from Inside Sales to our Operators to our Field Service Engineers, understand the challenges your operation faces. By leveraging our market contacts, in-depth knowledge and efficient operations, SES supplies a high quality product and service lacking in the marketplace. And our reliable, on-site service, repair and support solutions are designed to fit within your specific needs – and your budget.

And the best part is, we’re available 24 hours a day, seven days a week – and ready to travel around the globe when you need us most.

Stuart Porteous, Senior Vice President - Sales and Marketing, Marine & Transition Zone		Jamie Dozier, VP Marine Services		Patrick Ferrell, General Manager, Marine Technical Services		Joy Mitcham, MarineInside Sales Manager