GUERRERO, JUAN A., and BRETTON E. TROWBRIDGE, Terra Vac Corp., Costa Mesa, CA

ABSTRACT: Evaluation of Petrophysical Data for Vacuum Extraction Remediation

Classification of soils in the environmental industry is routinely accomplished using the Unified Soils Classification System (USCS). Use of this system in the remediation of soils with vacuum extraction has led to a reassessment of its applicability to in-situ remediation evaluations. The USCS has been inadequate in completely resolving the soil characteristics necessary for optimum design of in-situ vacuum extraction systems. Petrophysical analyses of subsoils targeted for remediation have augmented the engineering design and geological parameters required for successful vacuum extraction remedial programs. The accurate classification of soils and their properties is the single most important criteria in the choice or design of a system impacting such factors as the number of wells, well spacing, well construction and completion, well location, and even the type of vacuum extraction system to be considered. Proper descriptions and classification of soil types are essential in determining if vacuum extraction technology is applicable at a given site. We propose an approach to the evaluation of soils which considers parameters critical to the movement of vapors and liquids through the subsoils as a subsurface vacuum is propagated.

These critical petrophysical parameters impact the effective radius of influence of vacuum extraction in the subsoils and include permeability, porosity, grain-size distribution, sorting, fluid saturations, and soil stratigraphy. Petrophysical data is evaluated in the engineering design of several case histories where vacuum extraction technology was applied.

AAPG Search and Discovery Article #90992©1993 AAPG Pacific Section Meeting, Long Beach, California, May 5-7, 1993.