Abstract:
Over the last decade, there has been increased success at placing wells within productive
zones (sweet spots) of fractured reservoirs. Fractures are major pathways for fluid flow in the
reservoir and their exact positions must be identified and accurately mapped for optimal well
placement. On the standard seismic display, fractures often occurs below the seismic
resolution and are thus difficult to detect but recent advancement in seismic attributes like
similarity and curvature attributes are helping geophysicists to identify and characterize
them. This study is aimed at identifying and evaluating fractured hydrocarbon reservoirs
within ‘KIN’ Field by using the seismic discontinuity attributes and conventional well logs.
The workflow involved; wells correlation, petrophysical analysis, fault / horizon mapping
and fracture density prediction. Prior to the prediction and mapping of fractures, optimal data
conditioning was carried out using the Dip steering algorithm on OpendTectTM to remove the
seismic noises and improve the image quality of fractures. Time-slices were extracted within
the horizons of interest for seismic attribute analysis involving two discontinuity attributes.
Rose diagrams were plotted to reveal the predominant and orientation of the mapped
fractures. Conventional logs such as Resistivity, Sonic, Calliper and Density Logs were used
to validate the seismic mapped fractures within the borehole environment. Four sand units
(Sand 1, 2, 3 and 4) were picked and evaluated. Fractures influence on the petrophysical
properties of each reservoir (Sand 1, 2, 3 and 4) were also evaluated. A total of nineteen
faults (F1-F19) were picked on the seismic data. The attribute analysis results at time-slices
2024msec, 2100msec and 2197msec show subtle features (fractures) with SE – NW and SW -
NE predominant. Finally, possible new hydrocarbon prospect areas were located SW of the
field base on high amplitude from the Energy attribute and high fracture density from the
multi-attribute maps.
