oa Advancement In Geophysical Technology

During the last fifty years numerous advances have taken place in Geophysics as applied to the Oil and Gas Exploration and Development. This spans a development that started from single fold analogue data in the early 1950 through the digital revolution in the ’60 s and continues to the present date and hopefully well in to the future. The improvements have been in all phases of seismic method including data acquisition, processing, analysis and<br>3D visualisation volume interpretation. In data acquisition we can highlight the following changes : (1) from analogue recording to digital, (2) from single fold to multifold CDP, (3) from recording with a single component to all components of the wave field, (4) from surface seismic to acquisition on the sea floor, and (5) to imaging in a borehole or across boreholes. The concept of 3D earth mapping has enabled us to move away from 2D into 3D and to<br>mapping structure direct in depth rather than in time. Wider azimuths are not only possible in land but also in marine. Lately, the emphasis is on preserving geological and rock properties of the earth. With our growing knowledge of rock physics and its influence on the seismic wave propagation we are able to predict through the technology of DHI bright/flat spot and AVO/Inversion the possibility of detecting the presence of not only hydrocarbon and lithology but, under favorable conditions distinguishing oil from gas. Increasingly, geophysics is being applied for reservoir development, characterisation and even in Production to monitor fluid movement, depletion and aid in infill drilling covering the whole suit of Life of field. The other significant development is the proper use of 3D data volume in interpretation. With the aid of modern tools like 3D visualisation we are able to use the benefits of the 3D cube and its various attributes to interpret geological features in their true spatial location. This has helped us to identify complex stratigraphic features, improve our understanding of facies and fault patterns, their stress regimes and seal behavior , and to extend this to oil generation and migration history through synergy with basin modeling. The connectivity issue of reservoirs are now better understood by visualising the geo-bodies. In an Immersive Visualisation environment the geoscientists, reservoir and petroleum engineers, drillers, economists and managers can work together to make a collective techno-commercial decisions faster and better. This results is significant subsurface risk reduction and an improved chance of exploration success. The last 10 years have seen geophysical technology and capability explode and the coming years should be no exception. Geophysics will continue to give us more quantitative assessment of our prospects and reservoirs,including predict properties like : porosity ,gas saturation, absorption and possibly fluid flow and permeability. All these could aid us to drill more successful wells and be better hydrocarbon producers with last minute surprises. Geophysics is bringing geoscientist and the petroleum engineers closer together,and allowing the concept of a single “Shared Earth Model” to become a reality.