Print this pageAAPG GEO 2010 Middle East
Geoscience Conference & Exhibition
Innovative Geoscience Solutions – Meeting Hydrocarbon Demand in Changing Times
March 7-10, 2010 – Manama, Bahrain
Independent Simultaneous Sweeping in Libya - Full-Scale Implementation and New Developments
(1) BP Exploration, Sunbury on Thames, United Kingdom.
At the 2008 and 2009 SEG conventions (Howe et al 2008 and 2009) we reported on a proof of concept and initial production results of a new acquisition technique called ISS (Independent Simultaneous Sweeping).
This paper describes the successful full scale implementation of this method in Libya after it has been in use for more than one year acquiring a very large exploration land 3D survey for a project with a seismic commitment in excess of 13,000 sq.kms. We will describe the advantages of this method, some of the challenges imposed by this new way of working and some developments being evaluated.
Recent advances in recording systems allow for a recording spread to be continually active, which we refer to as continuous recording, although it may be more accurately described as recording of a set of contiguous records. This removes the necessity for real time synchronization of sources and recording systems. As long as the continuously recorded data and the source initiation can both be linked to the same time standard (e.g. GPS time) the traditional shot records can be extracted from the continuous dataset at any later stage. We have used the benefit of continuous recording to operate a large number of sources simultaneously on a large recording spread thereby greatly improving the productivity of land acquisition.
In this method all vibrators work independently without any attempt to synchronize their activity, and the underlying principle is that the interference between sources can be treated as noise.
In our simple and robust approach, there is no apparent limit to the number of sources that can be operated simultaneously, there is no waiting time for any vibrator and very little central control or communication is required.
It is very well suited for work in many environments including difficult terrain, where vibrator manoeuvering is slow, or where radio communication is challenged.
We demonstrate that this technique can deliver very high fold data at high efficiencies, such that it enables exploration land 3D to be acquired at costs comparable to marine exploration surveys.
We also describe early results from a field trial of ISS and a cable-less node recording system. Taken together, these two technologies might have the potential to change the way land seismic crews are configured and operated.