- Copyright © 2001 Society of Exploration Geophysicists
This paper shows part of the effort in Venezuela during the last eight years to record, process, and interpret multicomponent seismic data. We present the main results of three projects aimed mainly to help other studies in fracture, lithology, and heavy oil characterization in different types of geologic environments.
This field, in western Venezuela in the Barinas-Apure Basin, produces primarily from a fractured carbonate reservoir at a depth of 10 000 ft. The area is structurally simple. In early 1994, Pdvsa recorded in this field the first 3-C/2-D multicomponent survey in Venezuela to obtain information about fracture orientation and density at the reservoir level that could help design trajectories of horizontal wells.
The survey was designed to intersect existing well control and maximize data quality with respect to resolution and signal-to-noise ratio. Three 10-km 2-D multicomponent lines were centered over the reservoir along three azimuths. Lines 1 and 3 were parallel to the field's two main fault systems. Line 2 bisects the angle between lines 1 and 3, forming an angle of approximately 41° with line 1 (Figure 1). To avoid aliasing of surface waves, the geophone group interval was 17 m with a linear array between stations. The far offset was extended to 3600 m to allow converted-wave events to arrive outside the surface waves cone.
Figure 1 shows the behavior of migrated horizontal components around points 7 km from the beginning of each line. At the blue point on line 3, the radial component arrives faster than the transverse component. At the red point on line 1, the radial component arrives later. Similarly, at the green point on line 2, …