|
Seismic data is used by oil and natural gas exploration companies and energy trusts to identify particular prospective portions of geological formations that have the potential to hold hydrocarbons. Seismic is used in conjunction with well-logging data, well core comparisons, geological mapping and surface outcrops to create a detailed map of the subsurface at various depths. This is how oil and natural gas explorers select the location of new wells.
2D Seismic
Historically a large number of major oil and natural gas pools were discovered using 2D seismic. 2D seismic provides a geological section - a two-dimensional "slice" - of the underlying geology, and it can extend over a large distance. Intersecting 2D lines can enable explorers to map larger pools, but without the precision required for smaller or more complex targets.
Nowadays exploration companies typically use 2D seismic to get a sense of the regional geology of an area it thinks is prospective for oil and natural gas. It would then use 3D seismic covering smaller zones of particular interest to select individual wells. However, at times producers still drill using a combination of 2D seismic and geological work, especially when exploring larger structures or all-new areas where 3D seismic is unavailable or cost-prohibitive. 2D is still being shot in parts of the Foothills where exploration is just beginning. The large majority of new seismic data currently recorded is 3D. Pulse continues to build its 2D library by acquiring data sets.
3D Seismic
The advent of 3D seismic in the 1980s provided an enormous qualitative leap in mapping the subsurface. It allowed geologists and geophysicists to work together, dramatically reducing drilling risks. 3D seismic can justify its costs merely by avoiding a few unsuccessful wells. As drilling costs continue to climb and land access becomes more difficult, producers are relying increasingly on 3D seismic for exploration program. For certain types of targets 3D is virtually a prerequisite.
Shooting 3D seismic over very wide areas for a broad exploration program continues to be cost-prohibitive for most explorers. 3D seismic is generally used to zero-in on a discrete area of interest initially identified with 2D seismic. Typical 3D seismic surveys cover an area anywhere from a few square kilometres to several hundred square kilometres. The total coverage area of non-exclusive 3D data available to producers for licensing continues to increase in the Western Canada Sedimentary Basin, and Pulse is among the most active acquirers of new and newly available data.
|