Independent Simultaneous Sweeping

It is well known that higher fold and increased sampling is a sure path to improved data quality, and that vibroseis productivity rates are often the limiting factor on land 3D surveys. We want to find ways to use multiple sources simultaneously, so as to make a step change in both sampling density and productivity. In 2006 BP carried out a test of a very simple simultaneous vibroseis method, which we call ISS (Independent Simultaneous Sweeping). In this method all vibrators worked independently without any attempt to synchronise their activity, and the underlying principle of this test was that all interference between sources should be treated as ‘noise’. The noise was randomised as much as possible, and a standard suite of noise removal tools was used during processing. There was no requirement for specialised wavefield separation techniques. In this 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 manoeuvring is slow, or where radio communication is challenged.