Should Every Seismic Project Have a Positioning QC?
At Postplot, we believe they should.
Please read on and we will explain why and offer solutions for any project budget...
POSTPLOT
Postplot is a set of seismic positioning data QC solutions and is a collaboration between Julian Hillman and Ken Lanham.
We offer a range of services to exploration clients, contractors or consultant agencies, and these services are detailed here.
Between us, we have almost 80 years of seismic positioning experience on land, transition zone and shallow water marine (OBC/OBN) surveys. That experience spans more than 20 countries and includes working in production for contractors and as quality consultants for clients.
Some years ago, we both independently realised that many positioning errors were going undetected in seismic surveys due to a lack of dedicated QC software. While various software packages were available for positioning in land and shallow water surveys, they tended to be oriented towards production rather than quality control. While all of them have quality control elements, they did not focus on finding errors. Many of them were also cumbersome when trying to QC many diverse sets of data. We both realised that to do our jobs properly, we needed software that was designed from the user’s point of view, encapsulated as much of the user’s knowledge as possible, and was modifiable as new requirements were realised. The only way to do that was to write our own software. We have combined our various solutions to create a set of applications with a wide range of capabilities.
The primary responsibility of our software is to detect errors in a comprehensive but efficient manner. This requires the software to analyse the data presented to it in a number of different ways because different errors can be detected in different ways.
· Some of these problems can only be detected with check measurements.
· Some can be detected with appropriate procedures that allow for cross-checking.
· Some can be detected by comparing the supplied values against preplot or given tolerances.
· Some can be detected by scanning the data in tabular or graphical form.
· Some can only be detected by reprocessing the raw data and comparing it to the supplied values.
· Some can only be detected by generating an independent set of final data and comparing to the supplied values.
The first two solutions are field procedures and need to be implemented by the contractor. Solutions can be specified in the contract and compliance checked by a Positioning QC by examining the data.
The second two methods can usually be accomplished with readily available software or perhaps even some spreadsheet scripts, but can be time consuming using these solutions.
The last two solutions require very specialised software with the ability to read raw marine data formats such as P294, raw vibrator data such as VAPS, and others, process that data efficiently, and be designed to identify common errors. It also needs the ability to write to and retrieve from a database and perform comparisons and report on them. The Postplot set of applications is uniquely equipped with the tools to perform these tasks, as well as many other data tests that reveal common problems.
In Errors, we will try to describe the range of errors that can and do occur in seismic surveys, with many of these often going undected.
In Software, the tools we have developed to detect these errors are described.
In Services, we offer many lower cost alternatives as well as the traditional full on site QC services.