Shell Hits Four New ‘Large’ Sands in Gbaran Deep

Shell Nigeria is still on location at Gbaran-26, in Oil Mining Lease (OML 28), one full year after the well was spud.

But the patience is paying off. The country’s largest onshore operator has encountered four new gas sands, two of them below 16,300 feet True Vertical Depth. “They are very good reservoirs, thick and highly permeable sands”, impeccable sources at theDepartment of Petroleum Resources told Africa Oil+Gas Report. “And when the well is completed, it will simply be hooked up to the nearby Central Processing Facility”, which has the capacity to produce 1Billion standard cubic feet a day.

The Gbaran CPF supplies gas to the Nigerian Liquefied Natural Gas NLNG trains at Bonny. It is also scheduled to deliver over 70Million standard cubic feet per day (MMscf/d) of gas to the Gbaran Power Plant in Bayelsa State.

Shell has been battling overpressure since it reached around 15,000 feet over six months ago. After encountering two sands between 15,800 and 16,300 feet, it ran a seven inch (7”) liner all the way to the surface to stabilize the hole. Then it hit another set of sands below 16,500 feet. The current section of the hole, drilling at about 17,000 feet TVD, is quite slim; 5.5 inch. The equivalent circulating density (ECD), an important parameter in avoiding kicks, is close to 0.9, which is a high.

This is contrary to the experience by Conoil on the two Ango wells in Oil Mining Lease (OML) 59, which also encountered deeper pool pays. Here the  pressure was hydrostatic (normal) even as deep as 16,000 feet. Conoil deployed the Majestic, managed by Depthwize, the Nigerian rig operator. For Gbaran -26, Shell is using the Chinese built High Pressure, High Temperature (HPHT) Hilong 27 rig.

“The geology gets interesting”, the DPR sources say, “they’ve gone from coastal plain, been through the margin of the delta and they are going to proto delta slope facies”.

Shell has been touting the success of Gbaran-26, located in OML 28, for some time now, even as it encountered tough drilling conditions, but the company never gave details. At the Africa Oil Week conference in Cape Town last November, Allistair Milne, the company’s Vice President, Subsaharan African Exploration, presented a seismic profile showing the Gbaran-26 prospect. He spoke of growth potential in Nigeria, “particularly in onshore gas for domestic use and export”.


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