The Fractured Basement in Block 10 of Yemen: A Successfully Appraised Nonconventional Play

Langevin, Nicolas M.¹, Mark Been¹, Jerome Vidal² (1) Total, Paris La Défense Cedex, France (2) TOTAL E&P Yemen, Paris La Défense Cedex, France

In 1992, in their East-Shabwa license, Total E&P Yemen was the first Operator to discov­er oil in the fractured Basement in the KHARIR field located in the Jurassic to Lower Cretaceous graben. Being the secondary objective in the discovery well and despite a pro­duction test evidencing producible oil, the Basement was abandoned to develop the much better producing directly overlying prolific Cretaceous play.

In 1995, Basement was also found oil bearing in the nearby WADI TARIBAH field. Subsequent development in 1998 allowed initial production at 1000 bopd but eruptivity was lost within 3 months. Production has since been initiated by jet-pump at very low rates.

Appraisal of the Basement play in KHARIR was pursued by deepening development wells targeting the overlying conventional Cretaceous play. In a short period, several successful production tests were carried out in the Basement sections with production rates up to 7000 bopd.

After initial mechanical difficulties to obtain successful penetration in the Basement, part of the challenge remains the characterisation and the estimation of the oil in place of this non-conventional reservoir. With a seismic of medium quality, the assessment of fault schemes of deep horizons and the prediction of sweet spots remains difficult. Adding to these uncertainties are the production conditions near bubble point and incompatibility of produced effluent with existing production facilities. The combination of these elements has led Total to implement a phased development approach including early production facilities with a gradual increasing well count while the overall development plan for the Basement is being developed.

With the successful development of KHARIR, the fractured Basement reservoir has become a key exploration objective in and around the Jurassic to Lower Cretaceous graben in Yemen.