AUTHORS: Raffaele Di Cuia & Alberto Riva (G.E.Plan Consulting), Stephen Farner (Petromanas), Robert Konert & Eddie McAllister (Shell)
YEAR: 2014
“Reducing Subsurface Uncertainty & Risk Through Field-Based Studies” conference (The Geological Society, Burlington House, Piccadilly, London)
The Albanides thrust belt is characterized in southern Albania by a series of thrust zones that have involved in the deformation shallow water carbonates deposits (Kruja platform) and deep water carbonate units belonging to the Ionian zone. The deformation has created a series of complex structures that interact between them and also involve the Tertiary flysch deposits.
In one of these thrust zones (the Berati thrust zone) a recent new oil discovery was made in fractured basinal carbonate units. The matrix of the reservoir is characterized by low to very low porosity and permeability typical of open marine carbonate facies. This unit is affected by intense faulting and fracturing that represent the main permeability in the reservoir and possibly also the main storage for HC.
The available large grid of 2D seismic lines does not allow a complete and detailed characterization of the subsurface structure and of the fault network therefore a detailed outcrop geological study was undertaken to not only characterise the fault and fracture network at different scales but also to better define the geometry of the structures and their possible kinematic evolution.
The acquisition of more than 8000 structural measurements with different methods, the interpretation of satellite images, the detailed description of more than 1400m of Mesozoic section, the petrographic analysis of more than 100 thin sections and the geological mapping over more than 3000sqkm allowed the definition of a detailed geological model and the characterization of the fault and fracture network across the different structures.
The integration of the outcrop data with the available well data and seismic helped in better containing the geological model of the discovery and in planning the characteristics of the future appraisal wells.
The test results of the discovery well were also interpreted using the proposed structural framework to understand the potential of the reservoir in terms of deliverability.