Abstract: Use and Application of Organic Geochemical Techniques Related to Exploration and Production of Petroleum Reservoirs

Henning Jensen, Peter B. Hall, Sunil Bharati, Anne B. Talukder, Malvin Bjoroy

Petroleum geochemical data are essential to many aspects of reservoir evaluation, for example, in the detection of barriers to fluid-flow and the identification of different reservoir compartments. The analytical techniques used in reservoir geochemistry include bulk screening analyses (e.g. Rock-Eval and Iatroscan TLC-FID), detailed gas chromatographic analyses (e.g. whole oil GC) and compound specific analyses (e.g. thermal extraction GC-MS and GC-IRMS). New techniques which have proved to be particularly useful include Iatroscan TLC-FID and GC-IRMS.

Optimum sampling and analytical programs are crucial to acquiring sufficient data which are appropriate for specific reservoirs. Both fluid and rock samples are necessary for characterization of the petroleum populations present in the reservoir, as occasionally rock extracts are different in composition to the produced fluids. Sampling programs depend on the complexity of the reservoir, which can vary from simple "tanks" with relatively uniform petroleum requiring a relatively small sampling density, to highly compartmentalized reservoirs with very heterogeneous petroleum types. In both cases, however, a range of compound specific analytical techniques will be needed to discriminate between different petroleum populations.

Specific barriers to fluid flow such as tarmats and cemented intervals can be detected using screening techniques. Evaluation of filling point(s) and petroleum populations, reservoir comparmentalization etc. can be performed using quantitative and compound specific analysis data. Potential satellite field locations can also be identified bused on the knowledge of filling directions and other geochemical data.

The application of different analytical techniques in the assessment of reservoirs is demonstrated using examples from carbonate and clastic reservoirs of varying complexity.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France