3D SEISMIC REDUCES DRILING RISK
AND INCREASES POTENTIAL FOR EXPLORATION SUCCESS
Charlie Bukowski’s expertise in applying seismic exploration technology gives the Company a powerful edge in making new discoveries of economic hydrocarbons. He is especially skilled in interpreting reprocessed 3-D and 2-D seismic data to get the clearest possible images of a prospect. Most recently, using Pre-Stack Depth Migration (PSDM) analysis has further enhanced his ability to improve the image of a prospect. This analytical expertise:
- dramatically improves resolution of the subsurface.
- enables a more accurate pre-drill evaluation of potential reserve size.
- reduces risk, with the result that fewer dry holes are drilled.
- allows Bayou City to conduct more cost-efficient drill programs with greater potential for success.
HOW SEISMIC EXPLORATION WORKS
The word seismic refers to any earth movement, whether from an earthquake or a man-made tremor. Geophysicists conducting seismic exploration to find oil and gas record seismic vibrations, or waves, as they bounce back from geologic formations, to generate pictures of what the subsurface looks like. It is much the same as using sonar to create a profile of the ocean floor, except seismic waves are used instead of sound waves. Onshore, the vibrations come from specially designed vibrator trucks that "thump" the ground. In the past, dynamite explosions created the vibrations.
A seismic survey generates the vibrations, or waves, and records them after they have passed through or reflected (or bounced) off a specific target area. It’s like ripples in a pond reflecting off a boat in the water. A reflection seismic survey typically generates hundreds to tens of thousands of these seismic “shots,” at different locations. Geophones laid out in lines – or grids -- measure how long it takes the waves to leave the source (the vibrator truck), reflect off a rock boundary and return to the geophone, which record the ground movement as electrical voltage. This record of each shot is used to create an image, which is stored electronically for subsequent processing, display and interpretation.
FROM 2D TO 3D SEISMIC
The difference between 2-D and 3-D seismic lies in the number of vibrations recorded to serve as a basis for analysis. With 2-D, geophones along a line of vibrations provided a picture that was a cross-section, or slice, of a rock formation. With 3-D, the geophones cover a grid, not just a line. With thousands of times more data points, scientists can map a cube, creating a 3-dimensional computer image of the formation.
While 3-D is many times more expensive than 2-D, it allows Bayou City Exploration to avoid unlikely prospects and allocate funds more effectively to higher potential drill targets. While seismic data has typically been collected with the sources and receivers in straight lines, 3-D seismic requires a much denser grid of trails than the 2-D seismic.