San Leon Energy PLC, Dublin, found gas shows within a 23-m-thick reservoir section of sandstone and conglomerate with its Laayoune-4 well drilled on the Tarfaya conventional license of Morocco’s Sahara region.
Formerly known as El Aaiun-4, the well was drilled by Entrepose Drilling’s Cabot 750 rig, targeting Tertiary channel sandstones and with an expected TD of 2,000 m below rotary table.
San Leon says the reservoir thickness is 10 m more than expected, encountered some 100 m more shallow to prognosis, and confirmed the geological concept of a thick sand channel system.
Elevated mud gas readings, including measurements up to C3 in the shallowest sands, coincided with the logged reservoir section. The company says a gas-and-liquid kick was taken while drilling below the reservoir interval, leading to TD being called early on the well at 1,814 m below rotary table.
The mud weight used was relatively heavy at 14 ppg, and no measurable mud losses were observed while drilling the target interval, providing good evidence for the overpressured nature of the formation.
Laayoune-4 has now been suspended, pending further studies and to allow future reentry. San Leon and Morocco’s Office National des Hydrocarbures et des Mines plan to jointly apply for an 8-year exploration license. Blocks were awarded to the company in 2009 and 2012 (OGJ Online, Aug. 28, 2012).
During the first period of the new license, San Leon intends to acquire a 3D seismic survey across the multiple channels of the Tertiary play, one channel of which was drilled by the Laayoune-4 well. Based upon the results of the seismic, San Leon would consider the option of reentering the Laayoune-4 well—including testing—drilling an additional well, or both.