Contrasting Structural Styles of Major Fields Associated with Fold-Thrust Structures in the Offshore Campeche Bay, Mexico

Shankar Mitra¹, Juan Duran Gonzalez², and Jesus Hernandez Garcia^2
1 University of Oklahoma, Norman, OK
² Petroleos Mexicanos, Ciudad del Carmen, Mexico

Fold-thrust structures in the offshore Campeche Bay contain the largest producing fields in Mexico. These structures formed during three main periods of deformation: (1) Jurassic-Cretaceous extension, (2) Miocene compression, and (3) Pliocene to Recent extension. Synkinematic growth strata reflect the structural evolution associated with the different deformational episodes. The Cantarell-Sihil system, consisting of the Akal, Kutz, Nohoch, Chac and Sihil fields is Mexico's largest producing system, with reserves in excess of 14 BBO. The geometry of the Cantarell-Sihil structural complex varies along trend from a simple fault-related structure in the south, to a duplex consisting of the Cantarell and Sihil structures in the central part, to a more complex system consisting of compressive blocks separated by Tertiary normal faults in the north. The Cantarell-Sihil structures transition into an arcuate complex consisting of the Ku, Zaap, and Maloob structures along trend. These structures are faulted detachment folds cored by Oxfordian salt. The folds are associated with frontal thrusts, which detach in the Oxfordian salt, and merge asymptotically into the Maloob thrust. The Ku-Zaap-Maloob fields together contain proven reserves of 3.1 BBO. The transition from fault-bend folds and duplexes in the Cantarell-Sihil system to more rounded faulted detachment folds in the Kumaza system is related to variations in mechanical stratigraphy and shortening along trend. Three-dimensional models of the tops of key reservoir units constructed using 3-D seismic and well data, and balanced structural cross sections, provide accurate details about the geometry and kinematic evolution of these structures.