Objectivity Key to Seismic Survey Quality

Embrace Your Fears …

Don't be afraid of quality control.

In fact, when it comes to the quality control of a seismic survey, "QC" should not be feared, but embraced.

And, by the way, there are ways to make sure it's effective.

That's the view of Andrea A. Collins, with Exploration Consultants Ltd. in the United Kingdom, who presented a paper titled "Who Needs Seismic Quality Control — An Objective Approach" at last fall's AAPG international meeting in Cairo, Egypt.

She spoke knowing her audience: There are myriad views regarding the use and value of independent quality control on seismic surveys. Being objective is difficult, because sometimes the entire process, from deciding where to acquire data to producing the hydrocarbons, is not seen in its entirety by either the oil company or the geophysical contractor.

"Generally, any process that involves human participation is not successful 100 percent of the time. Everyone makes mistakes," Collins said. "Therefore, in order for an overall operation to be acceptable, it is advisable to check the output from each or a sequence of sub-processes while at the same time taking into consideration how each process is affected.

"There are many ways of achieving the same result, so as well as checking the repeatability, one can check by using a different method," she said. "Both are useful in different senses."

Quality control on a seismic survey is primarily applied to seismic and navigation data, health, safety and environment, crew efficiency and acquisition techniques. Although much quality control must be done automatically today due to the huge rate of data acquisition, a certain percentage of quality control is reliant on the personal presence of a quality control officer.

This is particularly necessary for independent processing checks using different algorithms and for start of survey checks, Collins believes, as well as decisions relating to quality throughout the survey.

"The most needs for quality control is when one's experience in the field with a seismic survey contractor is limited and when a firmer grasp of geophysical, positioning and acquisition disciplines is required," she said.

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Don't be afraid of quality control.

In fact, when it comes to the quality control of a seismic survey, "QC" should not be feared, but embraced.

And, by the way, there are ways to make sure it's effective.

That's the view of Andrea A. Collins, with Exploration Consultants Ltd. in the United Kingdom, who presented a paper titled "Who Needs Seismic Quality Control — An Objective Approach" at last fall's AAPG international meeting in Cairo, Egypt.

She spoke knowing her audience: There are myriad views regarding the use and value of independent quality control on seismic surveys. Being objective is difficult, because sometimes the entire process, from deciding where to acquire data to producing the hydrocarbons, is not seen in its entirety by either the oil company or the geophysical contractor.

"Generally, any process that involves human participation is not successful 100 percent of the time. Everyone makes mistakes," Collins said. "Therefore, in order for an overall operation to be acceptable, it is advisable to check the output from each or a sequence of sub-processes while at the same time taking into consideration how each process is affected.

"There are many ways of achieving the same result, so as well as checking the repeatability, one can check by using a different method," she said. "Both are useful in different senses."

Quality control on a seismic survey is primarily applied to seismic and navigation data, health, safety and environment, crew efficiency and acquisition techniques. Although much quality control must be done automatically today due to the huge rate of data acquisition, a certain percentage of quality control is reliant on the personal presence of a quality control officer.

This is particularly necessary for independent processing checks using different algorithms and for start of survey checks, Collins believes, as well as decisions relating to quality throughout the survey.

"The most needs for quality control is when one's experience in the field with a seismic survey contractor is limited and when a firmer grasp of geophysical, positioning and acquisition disciplines is required," she said.

Likewise, she added, it is also necessary when employing contractors without much experience.

"Most of the larger contractors provide their own QC, the methods of which are highly commendable," she said. "As there is a human element to this self-QC, however, independent QC is often required.

"If enough communication and training takes place and people work toward a common goal, we will be close to the optimum path for success."

Questions and Perspectives

As always, cost is an important factor in determining whether quality control is used.

"Is it worth it? How much do you need?"

Several points have to be considered in making these determinations, she said. These issues include:

  • How much experience has the contractor had — and how efficiently can they work?
  • What is their safety record? Do they have a safety system in place?
  • Can they communicate effectively with the buyer of the data and with each other?
  • Are the hardware and software systems reliable?
  • Is it understood what is acceptable and unacceptable?
  • Is it possible to test the systems for accuracy or are they contained within a "black box?"
  • Does the crew know the survey requirements?
  • How long have the crew been together?
  • If it is a marine survey, how long has the vessel been used for surveying? Is this the first trip since a major re-build?
  • Have the action points from the last HSE audit been closed?
  • Have the action points from the last technical audit been closed?

In the case of proprietary work, a person from or a representative for the oil company would normally quality control the survey during acquisition. This person should know what the oil company requires (geophysical targets, quality of acquisition) and be able to use this information for discussion with the crew during acquisition as well as at the pre-survey meeting.

"It is important that this information is transferred to the acquisition members on the crew, and that as many of the crew as possible are present at the pre-survey meeting," she said. "Everyone wants to be good at the job, and this meeting is a catalyst in that process."

For speculative work, an independent quality control officer has to be inserted into the equation.

"For a product to be sold, a buyer would normally want to know about the reliability and validity of the product," Collins said. "The producer — in this case, the seismic contractor — therefore requires a dataset that can be shown to be within the bounds of the buyer's specifications.

"Independent quality control is able to give added value to the dataset."

A Healthy Tension?

Not surprisingly, geophysical contractors have a different view of outside quality control measures.

"It is safe to say there is more than a healthy tension between the current turnkey contractual model, which shifts risk to the contractor, and a heightened QC scrutiny," said Chip Gill, executive director of the Houston-based International Association of Geophysical Contractors.

"If the contractor is forced to take on the risk, then the contractor should be given the flexibility to manage that risk," Gill said. "Introducing a QC element into the equation that has authority over the contractor's operations fundamentally conflicts with the turnkey contract concept."

Can the presence of an independent quality control officer prevent contractors from performing as effectively as they otherwise would?

Collins said that depends on the attitude of the QC.

"For an efficient operation, the quality control needs to communicate effectively and work with the contractor and client," she said.

Communications between the QC and the oil company should be made routinely, she added, and any changes or exceptions to a plan or to expectations should be noted immediately. Good communications help crew members to be more at ease — and helps the operation to proceed in a more efficient manner.

"By having a common aim it should be possible to work together constructively," she said.

Often it's simply about good manners, she added. The manner of people can make or break a survey — and good manners help depersonalize potential arguments and make for a more positive atmosphere, which is conducive to effective, efficient work practices.

First Steps

Planning and preparation are crucial to a smooth operation.

As much information as possible about the survey must be collected as soon as possible in time for any questions to surface and for the pre-survey preparation, she said. The quality control officer also has to be well informed, needs an understanding of the survey specifications and has to be able to apply them.

"It is so important for the QC to be present at the pre-survey meetings in order to understand what the objectives are and to meet the appropriate people face to face," Collins said. "This one-on-one meeting aids communication, since later e-mail is likely to be the only form of contact — and intended meanings sometimes aren't transmitted with that impersonal approach."

During the pre-survey meeting, specifications can be discussed and, ideally, there is enough confidence in the quality control officer's understanding of how the final product is produced that they are given permission to apply the specifications in a flexible manner.

"This confidence building can take time," she said, "so all opportunities to meet the appropriate people will help everyone in the long-term."

Collins said there is a critical need in the industry for young people interested in quality control work.

"There is a shortage of young QCs in the industry now who have had recent experience working for a contractor and that have used the latest technology," she said. "It is important, therefore, that we work together to ensure that younger people are frequently brought into the career system and that training is freely available.

"The chicken and egg situation exists, where QCs are not accepted if they have no experience," she continued. "As long as we are all aware of this situation, we should agree to cultivate the inexperienced QCs and give them the tools and opportunities they require.

"A reason why the work force is aging is because there are now fewer rewards for quality control personnel," she said. "This needs to change."

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