Abstract

Maximizing oil production by implementing appropriate latest technology is of utmost importance to meet the KOC's strategic goals. The Burgan Formation in the Sabiriyah field is of Cretaceous age and consists of three reservoirs viz, Lower, Middle and Upper Burgan. The Upper Burgan is broadly divided into seven lithological units. Among them, Upper Burgan 2 (UB2) and Upper Burgan 4 (UB4) litho units demonstrates comparatively good reservoir quality with sufficient lateral extension.

The Upper Burgan reservoir in Sabiriyah field is very heterogeneous and complex in nature. The reservoir was developed through vertical wells all these years. However, to enhance production contribution from this complex reservoir, a paradigm shift in development strategy was adopted. Accordingly, a first ever non-conventional well (NCW) was planned, successfully drilled and completed with ICD.

The detailed geological studies and information from dynamic data were integrated in identifying the target. The twenty feet UB2 layer in less explored eastern part of the field was finalized as the target for NCW and the proposed location was further evaluated using full field modelling. The UB2 layer in that location has three sand units viz. upper, middle and lower. Each sand unit was separated by a prominent shale layer. The NCW was planned in such a manner to target all the sand units of UB2 optimally and stratigraphically step down /drill through the shale units in between the sand units. The NCW was drilled with the horizontal trajectory in the UB2 layer as per the plan. A total of 1800 feet of lateral section was encountered with an average porosity of 20 per cent while the permeability reached up to 1 Darcy in certain intervals. The test results of this well are highly encouraging, paving the way for future NCWs to enhance production from the Upper Burgan Reservoir.

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