A new integrated interpretation and visualisation tool has been designed by StatoilHydro and Landmark to predict rock type (lithology) and fluid variations from three-dimensional seismic and well data.
This will enable asset teams to evaluate prospects rapidly, improve reservoir property prediction and reduce uncertainty.
One way of reducing vast amounts of seismic information to more manageable volumes is to use an averaging technique known as stacking.
Although data stacking increases the signal-to-noise ratio and reduces the size of datasets by a factor of at least 10, however, it is impossible to recover all relevant information once this has been done.
So pre-stack seismic data are required to resolve the more subtle effects of lithologies and fluids upon them.
Seismic lithology and fluid prediction (LFP) analysis has largely been carried out on an ad hoc basis by oil company specialists because standard seismic interpretation software faces limitations in accessing and handling vital pre-stack seismic data.
A seismic line is selected from a reservoir map where it passes through a subject well (well A) and displayed as a stacked seismic cross-section (upper). The new integrated LFP software (lower) is then invoked to display all relevant seismic and well data pertaining to that well. Armed with this wealth of information, geoscientists can rapidly generate seismic attributes to improve their determination of features such as oil/water contacts and reservoir rock fluid contents (in this case, sandstone).
Abbreviations: sand – sandstone; Sw – water saturation; PhiT – porosity; Vp – pressure wave velocity; Vs – shear wave velocity; Rhob – density.
Over the past few years, StatoilHydro geophysicists have been working with Landmark to develop a new tool capable of being run on classic workstations for integrated interpretation of pre-stack seismic and well data.
Coupled to an efficient data storage system, this solution will make the technology more accessible to StatoilHydro staff as well as furthering multidisciplinary cooperation.
Present computers are fast enough and disc space is cheap enough to bring pre-stack seismic to every interpreter’s desktop – a revolution in the making.
