TABLE OF CONTENTS There are many tools and techniques for characterizing oil and gas reservoirs. Seismic reflection techniques include conventional 2D and 3D seismic, 4D time-lapse seismic, multi-component seismic, crosswell seismic, and advanced processing techniques to enhance resolution and bed detection. These techniques are constantly being improved. Drilling and coring a well provides the "ground truth" for seismic interpretation. Rock formations are directly sampled by cuttings and by core, and indirectly characterized with a variety of well logs. More sophisticated logs are also available, including borehole image logs for imaging the borehole wall and measuring z and structural features, and nuclear magnetic resonance logs for evaluating fluids and rock permeability. To maximize characterization, as many of these tools as possible should be employed. It is often less expensive to utilize a wide variety of tools, which measure reservoir properties at different scales, than to drill one or two dry holes.
