Donald L. Howlett

McKittrick Cross-Well Seismology Project: Part II. Tomographic Processing And Interpretation

A modified SIRT algorithm was used to invert crosswell seismic data acquired in the McKittrick Field, California. The resulting tomogram successfully imaged a complex fault system associated with the McKittrick Thrust. The fault-controlled reservoir was delineat,ed with a resolution of 40 ft [12.2 m] providing the geologists and production engineers with detailed geology and reservoir heterogeneity informa.tion previously unavailable. The McKittrick Thrust system consists of a main thrust and numerous subthrusts. The tomogram suggests that, a fault plane associated with one of the subthrusts is actually flatter than previously believed. We cross-checked the tomogram-derived interpretation for the McKittrick Thrust system with kinematic structural modeling (balanced cross section method) and found that, the McKittrick Thrust and its associated subthrusts can be classified as an imbricated fault-bend fold structure. Oil saturation for the reservoir was also estirnated from the seismic tornogram by exploiting an empirically derived relationship among oil saturation, temperature, and seismic p-wave velocity. The estimated oil saturation agreed with the average oil saturation values measured in the laboratory.

Implosion type energy source for seismic exploration

An acoustic energy source or gun for use in an aqueous environment such as in a borehole, a well, or in open water. The apparatus, when lowered into a water occupied borehole or the like, functions to create a series of acoustic impulses without forming bubbles, as a result of the water rapidly infilling an implosion cylinder or chamber. A piston rod assembly is reciprocally mounted in each acoustic chamber and is actuated by a power source to trigger the desired sound creating series of impulses.