Moreover, the application offers a multitude of editing tools, designed to make the creation process faster and easier. Although the idea of slant arrays had not been considered at the time of these tests, the data acquired allows us to compare the noise recorded by the in-line and bunched phones in what was an area of high village activity with numerous trees coupling wind noise.LayoutEditor is a comprehensive program that allows you to quickly create, modify or export layout designs for MEMS/IC products. The two lines ran parallel and were separated by about 4m. One line was a noise spread with a 5m group interval deploying bunched phones (12 in a 1m diameter circle), the other was a section of the production spread with a 25m group interval deploying an in-line 12 element 25m array.
The start-up experiments included shot depth tests into 2 parallel receiver lines separated by about 4m and extending over a distance of about 1km. The receiver types included geophone arrays and flushed hydrophones on land and OBC phones in the rivers. This survey was to include explosive sources on land and airgun sources across numerous rivers. In December 2005 a set of pre-start up tests was conducted by Chevron and Grant Geophysical for a 2D seismic program in Southern Bangladesh. In this paper we show that due to the omni-directional nature of the ambient noise, seismic data quality is significantly improved by retaining the 25m array length wherever possible and avoiding obstructions by allowing the array to be layed out in any direction. Unfortunately, in-line arrays on seismic lines passing through villages are often impossible to lay out due to obstructions and the traditional compromise has been to use a bunched phone array. An effective receiver group for shot-generated noise in many parts of Bangladesh has been shown to be an in-line array of about 25m. The landscape is partially inundated and scattered with villages and trees situated on higher ground and man-made levee banks. Population density in Southern Bangladesh is high and village activity produces high levels of ambient noise during seismic acquisition. This technique has been used successfully during production acquisition through villages in southern Bangladesh. Field experiments have shown, however, that arbitrarily oriented linear arrays are more effective at reducing ambient noise than bunched phones. A practical operational procedure in these areas has been to bunch phones. In these village areas, obstructions often prevent laying out in-line arrays. Both the cultural noise and the tree-coupled wind noise have directional properties which are not related to the seismic line orientation. Trees grown in these village areas for food and shade are believed to couple a significant amount of wind noise into the ground. The properties of this noise suggest it’s origin is in many areas dominated by cultural activity: village activity, farm machinery and people walking on the line sometimes in close proximity to individual geophone elements. This noise reduction is clearly evident on stack data with typical fold of 40. Arbitrarily oriented linear arrays (nominal 25m length) are more effective than bunched phones for reducing ambient noise on seismic lines laid out through populated villages in southern Bangladesh.
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