Chalco, Alejandro A.1
(1) Pluspetrol Norte, Lima, Peru
ABSTRACT: Carmen Field: Increasing Reserves and Exploration Potential with Sequence Stratigraphy
Carmen Field, discovered in 1974 at the northern part of the Marañon Basin (Perú),
was considered a marginal oilfield in a low relief anticline. In year 2002 an exploratory
well drilled over a seismic anomaly to the East of the field encountered a field
extension.
Seismic stratigraphy, cores and image logs, identified a depositional control for this
extension that increases proven reserves sevenfold, opening the possibility of further
extensions and of a new play concept for the Marañon Basin.
Frequency filters applied to Carmen 3D seismic highlighted a “doublet” inside
the reflector of Vivian formation, the main reservoir in the basin. While correlating the
doublet along 2D and 3D seismic, “clinoforms” were identified. These
“clinoforms” form in plan-view two NW-SE trending thickness anomalies
(“lobes”).
Wells drilled into the “lobes” encountered a thicker reservoir interval than
expected. Core and image log data show drowning surfaces separating a relatively
continuous fluvial dominated reservoir in the lower part of Vivian from a more
heterogeneous, thinner and laterally discontinuous fluvio-estuarine upper part of Vivian.
Integrating all the data and applying sequence stratigraphy techniques, a late LST was
assigned to the Vivian Formation.
The seismic data shows different parasequence stacking patterns for each “lobe”.
As matter of fact, core and production data from the wells indicates that each
parasequence has different reservoir properties.
Mapping the late LST “lobes” revealed additional areas with
“stratigraphic” trapping potential waiting for future seismic acquisition and
drilling in the area.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.