Tectonic-Sedimentary Evolution of Piedra Clavada and Koluel Kaike Fields, Golfo San Jorge Basin, Santa Cruz Province, Argentina

Schiuma, Ariel¹; Crovetto, Carolina B.; López Alvarado, Ornella M.; and Rasgido, Adrián O.
¹[email protected]

Piedra Clavada and Koluel Kaike fields are located in the south flank of Golfo San Jorge Basin, Argentina, where the basin has an extensional behavior with principal faults of NW-SE strike. The source rock is Pozo D-129 Formation, and the main reservoirs belong to Cañadón Seco Formation and in a lower proportion to Mina del Carmen Formation. This study was performed to better understand the potential of this last Formation.

Based on seismic character and electrical response of well-logs, the top and base of Mina del Carmen Formation (MdC) were established, defining three sub-units named MdC-A, MdC-B and MdC-C from base to top. Structural and isochoric maps were generated. Seismic attributes were computed to identify the paleofluvial systems, representing the principal reservoirs.

To determine the tectonic control on the sedimentation, the kinematical behavior of the principal fault was analyzed by computing the vertical throw for each of the interpreted horizons along the fault strike.

Isochoric maps and fault displacement graphics allowed us to define the paleogeomorphological framework, identifying the paleohighs and the paleolows. The main fault is composed of several segments which have been linked during its evolution, serving as access paths for sediments from the footwall to the hanging wall.

Two log-facies were identified by analyzing the well logs: a coarse facies (CLF) and a fine one (FLF). Log facies proportions were computed in every sub-unit, allowing us to qualitatively infer the amount of sediments supply.

During the depositation of MdC-A, the fault presented moderate activity; there were several small depocenters in the hanging wall, and sediments reached them through the relay ramps flowing parallel to the fault strike. The highest fault activity took place during MdC-B depositation, generating a big accommodation space with more integrated depocenters. Sediments continued entering through the relay ramps, especially those located in the eastern and western fault tips, and were transported parallel to the fault strike to the depocenters. Finally, during the deposition of MdC-C, the fault activity ceased and accommodation space was generated by thermal subsidence. Therefore, sediments were carried to the north towards the basin depocenter.

These changes in the paleomorphological framework conditioned the placement of reservoirs within MdC formation. This study will allow us to identify the locations for future drilling prospects.

AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013