Melbana Energy Limited reported that the Zapato-1 exploration well being drilled in its Block 9 PSC onshore Cuba (Melbana 30%) continues to drill ahead in hard volcanics, having reached a depth of 2,880 mMD earlier today. Based on interpretation of the available information, the well is now possibly immediately above the seismic reflector which represents the base of the ophiolite sequence. For the more technically inclined, the depth of the base of the ophiolitic sequence has been updated with the benefit of a synthetic log-based well to seismic tie derived from information gathered on the logging run of the previous section of Zapato-1. The greatest unknown presently in the interpretation is the velocity of the sequence.

It has been demonstrated that the initial pre-drill velocity was much slower than the actual velocities of the sequence. A re-interpretation of the depth of the base of the ophiolites using the updated velocity estimates the base of the ophiolites at around 3000 mMD. However, with the velocities the company are experiencing, one seismic couplet represents approximately 150 metres of depth, giving a large margin of error for predictions of when the company might encounter the target formation.

Whilst the velocity required to match the drilling result has changed, the initial seismic interpretation of the sequence has not changed. There is a confident seismic horizon tie with the Bolanos-1 well to the north-east, which reached total depth in Vega Alta shales, the interpreted top seal to the prospective A2 lead.