Following the successful application of high-resolution seismic to Tertiary clastic reservoir description in the Offshore Mexico area, (Salter et al, 2004), this study details the subsequent application to reservoir description of carbonate reservoirs of Mesozoic age in the Arenque and Lobina field areas. A survey of 320 km2 was acquired with the express intention of helping to guide new well locations.
In this paper we present an integrated approach to this reservoir characterization study. It benefits from the combination of Q seismic survey evaluation and design (Q-SED), high quality seismic acquisition and advanced data processing to prepare the data for its reservoir description objectives. The reservoir analysis following processing provided a much clearer understanding of the structural and stratigraphic controls over an existent field area, as well as a new field area, than had been possible to interpret using conventionally acquired and processed seismic data. The ability to map discretely key reservoir units within the Mesozoic provided a structural framework through which reservoir properties could be accurately mapped. The quantification of reservoir properties such as porosity were driven by detailed rock physics analysis allowing the construction of high quality attribute maps pinpointing key areas of interest for new well locations.
This study was directly used to assess four potential drill locations and resulted in the order of drilling preference being altered. A well in the Lobina field area was also successfully sidetracked to target a thicker section of the main reservoir facies as a result of interpretation performed on this new survey.
The Lobina Q survey was acquired through September and October 2003. The survey was shot for the primary purpose of
Improving upon a conventional 3D seismic survey shot over the same location in 1996.
Improving the amplitude fidelity and vertical resolution to accurately delineate prospects previously defined. It was clear that increasing maximum recorded frequency to 60Hz over the target interval, along with good signal to noise separation, compared to 30 Hz from the conventional data would significantly enhance the capability of mapping key reservoir layers.
Interpreting and characterizing the reservoir units, primarily the Cretaceous Tamaulipas (Kti) and Jurassic San Andres (Jsa), in terms of structural and stratigraphic complexity in addition to reservoir property prediction and distribution.
This paper describes the major steps taken in this case study and illustrates the key reservoir features that are only visible when advanced processing is applied to high quality seismic data.