Wentworth updated operations of the Ziwani-1 exploration well in the Mnazi Bay Concession, Tanzania.
The well, which was spudded on February 1, 2012, has now been drilled to a depth of 8,763 feet (2,671 meters) and full logging operations have been completed. Further to the announcement of April 10, 2012 regarding the encountering of gas shows, the partners have identified a gas bearing zone between 3,629 and 3,638 feet (1,106 and 1,109 meters) and are conducting testing operations. The zone to be tested is a new reservoir interval, not previously encountered in the Mnazi Bay Block. The reservoir is a clean limestone of Pliocene age which exhibited strong gas shows during drilling (4.3 percent Total Gas). Petrophysical interpretation of wireline logs indicates a pay zone with 17 percent porosity and 78 percent hydrocarbon saturation indicating good reservoir quality. A Drill Stem Test will be conducted to establish the flow rate which can be achieved from this reservoir interval. Although several sandstone intervals of Oligocene/Eocene age were penetrated deeper in the well, logging proved these to be water bearing. The well has now been plugged back to enable the Pliocene limestone to be tested.
There can be no assurance that any flow rate achieved will prove to be commercial but the information acquired is expected to be valuable in respect of knowledge of the basin for further exploration. Wentworth will provide further information once the well test is complete.
About the Mnazi Bay Concession
The Mnazi Bay Concession Area is located in coastal, south-eastern Tanzania in the Ruvuma (Rovuma) Basin. The area lies between Aminex and Solo Oil's Ruvuma Concession Area and Ophir Energy and BG Group's offshore Block 1. Ophir and BG Group's Chaza-1 gas discovery lies just northeast of Mnazi Bay's marine border. The 292 square miles (756 square kilometers) concession area contains two discovered Tertiary aged gas fields (Mnazi Bay and Msimbati) and holds additional Tertiary, Cretaceous and Jurassic hydrocarbon potential. Five wells have been drilled to date: MB-1, MB-2, MB-3, MS-1X and Ziwani-1, and all five wells encountered hydrocarbons. MB-1 is currently producing gas at a rate of 1.7-2.0mmscf/d and this gas is transported via an 8", 16.77 mile (27 kilometer) pipeline to the Mtwara Power Plant where it generates electricity for numerous local communities.
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