SPATIAL CLUSTERING - USING SIMPLE SUMMARIES OF SEISMIC DATA TO FIND THE EDGE OF AN OIL-FIELD

The positioning of development wells for efficient production from an oil-field depends critically on being able to find accurately the edge s of the reservoir. We address this problem by using as the basic data over 1000 short time series collected by seismic reflection profiling . All the time series extend over the 'reservoir interval', i.e. the s ection of rock potentially containing hydrocarbons. Each time series i s first reduced to three physically meaningful variables. These variab les capture information on the sand/shale ratio in the reservoir inter val at the location of the time series. Spatial changes in this ratio will be expressed in the three variables extracted from the set of tim e series, the locations of which also vary spatially. The cloud of thr ee-dimensional points is then subdivided by using the graphical tools of spinning and projection pursuit, and the edge of the oil-field is h ence delineated by mapping these clusters back into their geographical co-ordinates.