Structural analysis of a naturally fractured carbonate field in the south-east Gulf of Mexico.

Abstract

Fractured carbonates produce more than 85% of hydrocarbon production in Mexico. A large number of the producing fields are located in the South Gulf Salt Province (SGSP) in Campeche Bay within the Upper Jurassic Kimmeridgian and Cretaceous carbonates. Multidisciplinary analysis involving structural and stratigraphic interpretation, integrated with fracture analysis is needed to efficiently produce from these fields. This study focuses on the structural geology and fracture analysis of two structures (A and B) in the area. As well as in the inquiring of the most important mechanisms involved in the formation of the most critical hydrocarbon traps and principal reservoirs. The structures formed during four main periods of deformation, including (1) upper Jurassic to early Cretaceous extension (D1), (2) Eocene-Oligocene compression (D2), (3) Middle-Upper Miocene compression (D3), and (4) late Miocene to Recent extension (D4). The deformation resulted in broad faulted detachment folds superimposed on salt pillows. Numerous secondary faults related to episodes D2-D4 are mapped on the structures. Although a number of fracture sets related to the multiple episodes of deformation are present, the main sets of open conductive fractures are transverse (type1), and longitudinal (type 2). The principal factors controlling the presence of the naturally fractured carbonate reservoirs are related to the lithology, and local deformation discussed.The interpreted structural geometry, evolution, and fracture patterns will be critical for future production from the Cretaceous reservoirs.