Managing simultaneous operations during seismic acquisition in offshore fields

SIMOPS management will optimize conflicting activities during complex seismic surveys in congested offshore producing fields. Photo by Harald Pettersen, courtesy of Statoil.

Every year, conflicting activities during complex seismic surveys in congested offshore producing fields cost operators millions of dollars in lost time. Worldwide, large numbers of seismic vessels encounter unexpected interference and unnecessary delays, due to simultaneous operations (SIMOPS) taking place within, or overlapping, their survey areas. Traditional manual processes and spreadsheet programs are no longer effective enough to prevent costly SIMOPS conflicts in increasingly chaotic environments.

COSTS OF SIMOPS CONFLICTS

Actual collisions between seismic surveys and other marine traffic are rare. Unfortunately, when they happen, they can be quite expensive. A few years ago, for example, a container ship ran over the tail end of an 8-km, towed streamer array during a 3D seismic survey in the Gulf of Mexico, causing a reported $25 million in damages. Why did the ship collide with the array? The main reason was the loss or failure of what human factors engineers call “situation awareness” (SA). Simply put, crew members didn’t understand what was going on around them at the time.

This event illustrates one type of SIMOPS conflict that can occur, even in open waters. In congested areas around active drilling rigs and producing platforms, failures of situation awareness are, sadly, more common. According to the World Offshore Accident Databank, between 1980 and 2002, there were 326 collisions between marine vessels and offshore petroleum installations. From 2001 to 2011, 26 such collisions occurred on the Norwegian Continental Shelf alone. In 2014, an offshore supply vessel struck an oil production platform in the North Sea, forcing workers to evacuate. The operator had to shut down for at least one day, resulting in approximately 8,000 bbl of lost production. 

However, for seismic contractors acquiring critical data in busy producing areas, the most common challenge is not an actual collision. Rather, it is the steady accumulation of small delays and interruptions caused by seemingly unavoidable SIMOPS conflicts within the survey area. Examples include divers or remotely operated vehicles (ROVs) performing maintenance and repair activities, support boats coming and going unpredictably, and oil tankers arriving with insufficient notice at a floating production storage and offloading (FPSO) vessel.

How frequent are SIMOPS conflicts, and how much do they cost operators? Consider the following situations encountered by ION Concept System’s survey planning and optimization specialists.

Two years ago, an E&P company in the North Sea decided to acquire a new regional 3D survey covering about 20 producing fields. In addition to 26 active offshore facilities, four major shipping lanes ran through the survey area. ION’s task was to manage SIMOPS and design survey plans to avoid having to break off while shooting any particular line. Many line plans required four or five passes, per day, by platforms or drilling rigs, which had 500-m exclusion zones and considerable marine traffic.

Every time a seismic vessel with towed streamers is forced to abort a line due to an unforeseen SIMOPS event, roughly six hours are lost turning around and starting over, or moving to another line. At a typical rate of $225,000/day, each 6-hr break-off would cost the company $56,250. Realistically, without excellent SIMOPS management, a regional survey like this could have suffered at least three break-offs per week. Over the four-month survey, therefore, 48 apparently “small” lost-time incidents at $56,250, each, would have accumulated $2.7 million in unnecessary expenses.

Fig. 1. MARLIN provides a common operational view by integrating the operation plan and vessel tracking information in a single view.

Even a single SIMOPS conflict can cost millions of dollars in certain situations. For example, near the end of a 4D survey close to an FPSO anchored offshore Angola, the operator abruptly suspended seismic acquisition, even though only two lines remained. An oil tanker was scheduled to arrive, so the FPSO’s exclusion zone had suddenly expanded to ensure safety. However, the tanker was unexpectedly delayed for four days. There were no other lines to shoot, so the survey vessel was forced to wait until after the tanker had departed. At $300,000/day, the operator incurred an extra $1.2 million because of that one delay.

OPTIMIZING SIMOPS SAFETY, EFFICIENCY

To manage simultaneous operations during a seismic survey in the vicinity of active production facilities, some operators place a dedicated SIMOPS specialist on the contractor’s vessel. This individual is responsible for contacting all parties expected to operate in the area. He obtains everyone’s plans and schedules by phone, radio or email. Typically, he uses spreadsheet software to create a Gantt chart of all simultaneous or overlapping activities (Fig. 1), and sends a PDF file with the corresponding plans to all authorized parties. Some operators hold daily meetings, and manually update the SIMOPS chart every 12 or 24 hr.

Between those updates, however, various delays and unplanned conflicts often occur, triggering a cascade effect that can slow down or completely stall seismic acquisition. Conflicts also can increase noise and reduce seismic data quality. Unfortunately, existing SIMOPS spreadsheets provide only high-level overviews. They are incapable of capturing changes taking place hour by hour. Nor can they provide the exact geographic location of any activity. They simply cannot visualize the relative—and constantly shifting—spatial positions of multiple operations and their safety exclusion zones.

A few years ago, for example, the dive master at a producing platform in the North Sea was concerned that the use of air guns for a 4D survey in the area would harm his divers. So the seismic vessel was not allowed to come within 10 km of the platform. Neither operation knew each other’s plans, including the timing and location of potentially overlapping activities. A series of phone calls, emails, and last-minute negotiations were necessary to avoid a costly delay. As it turned out, the seismic operation only came within the 10-km exclusion zone for a mere 30 min.—at a time when no divers would be in the water.

Some companies consider unplanned downtime an unfortunate but inevitable “cost of doing business.” However, given the day rates for marine operations and the sheer number of potential conflicts in congested areas, operators would gain enormous value, if they could manage SIMOPS in real time.

Fig. 2. In the calendar view, operational activities may be entered, similar to Gantt charts.

Based on extensive experience planning, acquiring and optimizing marine seismic surveys worldwide, ION developed a new collaborative SIMOPS management system that can improve the safety and efficiency of all simultaneous operations—not just the seismic survey, itself—within a particular geographic area.

In addition to survey vessels, any operation within the survey area—platform, FPSO, supply boats, diving and ROV operators—can install the new SIMOPS software. All SIMOPS users offshore are linked with each other, and with the operator’s office onshore, if desired. Authorized users define their own tasks, identify when and where they will take place, and set exclusion zones with alarms around them.

Multiple SIMOPS plans are consolidated in a shared calendar tool, or interactive Gantt chart, which is dynamically linked to a map of the field showing the entire local infrastructure, Fig. 2. As a result, everyone with the new SIMOPS technology has a common temporal and spatial picture of all operations in the area. Clicking an object in “map view” brings up current operational information. When certain activities are delayed or plans change, the system automatically updates all authorized parties in near-real time. Visibility into operational changes enables otherwise isolated participants to negotiate solutions to conflicts, and to build trust.

All electronic information in the system is automatically geo-referenced and time-stamped, so users can visualize multiple layers of GIS data in a single, integrated display. Manual entries and observations also can be fed into the system. Throughout seismic acquisition, the SIMOPS system regularly accesses navigational data and updates the position, speed and heading of the seismic ship, streamer array, and any other vessels in the area. The SIMOPS calendar also provides an innovative time-sliding capability. This allows users to slide forward or backward in time through the interactive Gantt chart, presenting an animated movie of all operations in map view. This enables both the seismic contractor and other parties to predict potential SIMOPS conflicts, and proactively adjust plans to mitigate them.

Fig. 3. Alert zones may be assigned around objects, and alarms triggered, when objects breach the perimeter.

Linked to marine radar, the SIMOPS system also detects the AIS (Automatic Identification System) signal of any approaching vessel, whether it has the SIMOPS software or not, and triggers a pre-set alert if it crosses into a restricted zone, Fig. 3. Finally, the system automatically logs all SIMOPS incidents and events that may occur during seismic acquisition—how close other vessels came, at what times, for how long, and so on. 

ENHANCING SITUATION AWARENESS

Collisions and other SIMOPS incidents occur when operators in chaotic environments suffer a loss of situation awareness. Situation awareness occurs at three levels: 1) perceiving or being aware of critical information within the environment; 2) comprehending the meaning of that information in an integrated manner; and 3) projecting relevant elements into the near future, to make wise decisions and take appropriate action.¹ Situational awareness can be thought of as a mental image of the current state of the operator’s environment, and this image forms the basis for all decision-making and action.

An in-depth analysis of SA errors in aviation incidents found that the majority—78%—occur at Level 1: people simply do not get the information they need. Another 17% occur at Level 2: they do not understand the data, even when they have it. And 5% of SA errors occur at Level 3: they do not predict correctly what will happen next.²

When researchers at the University of Aberdeen analyzed offshore drilling accidents, the numbers they found were comparable.³ Of 237 reported incidents during a nine-month period, for example, 135 were directly related to errors of situation awareness. The majority of those—67%—were Level 1 errors, while 20% were Level 2, and 13% were Level 3 errors. Presumably, errors of situation awareness during seismic surveys and other simultaneous operations in offshore producing fields would follow a similar pattern.

Extensive research and engineering experience in SA shows that one of the most effective ways of increasing situation awareness is through better technology. Systems should be designed, not only to gather diverse data from multiple sources, but also to present relevant information in a single integrated picture, as well as enable users to accurately project changing conditions into the near future.

Fig. 4. Spatial views allow the prediction of conflicts.

ION’s new seismic SIMOPS technology can enhance situation awareness at all three levels. At Level 1, the hosting service assembles critical field and operations data from all parties within the survey area, both before and during seismic acquisition. As soon as the timing or location of any operation changes, that information is uploaded to the system and automatically distributed to every SIMOPS user in the field.

At Level 2, the interactive SIMOPS calendar and map views intuitively integrate temporal and spatial information on a single screen, Fig. 4. Everyone can see both the big picture and all the details. Automated alarms and notifications further enhance the meaning of rapidly changing conditions. At Level 3, the time-sliding feature, integrated with the calendar and map, allows survey optimization specialists—and other SIMOPS users on the system—to quickly visualize the future positions and movements of every operation in the area.   

REFERENCES

1. Endsley, M. R., “Toward a theory of situation awareness in dynamic systems,” Human Factors 37(1), pp. 32-64, 1995.
2. Jones, D. G., and M. R. Endsley, “Sources of situation awareness errors in aviation. Aviation, Space and Environmental Medicine, 67(6), pp. 507-512, 1996.
3. Gomez, C., and D. R. Green, “The impact of oil and gas drilling on EU fisheries,” 2013.