Improving structural and stratigraphic interpretation using borehole‐integrated seismic processing — Ledjmet block, Algeria

Fig.1 Berkine Basin Oil and Gas Trend – more than 5 Billion Barrels of oil discovered to date. First Calgary Petroleums Ltd. (FCP) along with its partner Sonatrach (National oil company of Algeria) has drilled several successful exploration wells in the Ledjmet Block 405b of the Berkine basin, Algeria within the last two years (Fig.1). 2D data of different vintages could not provide an accurate interpretation; therefore two 3D seismic surveys (~850 sq km) using vibroseis 100-fold parallel-geometry were acquired. This acquisition geometry allowed a better sampled offset distribution (50-5000m) in the CDP domain. This also resulted in effective noise attenuation, a better velocity analysis, improved S/R (Signal-to-Noise Ratio) and a stable full Kirchhoff Pre-Stack Time Migration (KPSTM). Despite careful planning and utilizing all the knowledge available at the time, the 3D processing was faced with several challenges in terms of statics, noise (random, linear, multiples and acquisition footprint), and most of all velocity analysis. These all had an effect on the integrity of structural and stratigraphic interpretation