Logging Services Used for Large Diameter Boreholes

Abstract

American Institute of Mining, Metallurgical, and Petroleum Engineers Inc. Abstract Logging of large-diameter boreholes for formation evaluation and as an aid to construction has become a routine procedure at the United States Energy Research and Development Administration (ERDA) Nevada Test Site. Many of these logging services are being used in commercial applications such as mine shaft construction. Log interpretation has been altered to account for conditions of 121-cm (48 in.) to 304-cm (120 in.) diameter boreholes, generally above the water table, and penetrating volcanic rocks. The methods are described and log examples and photographs of the borehole instruments are shown. Application of the data is discussed. Introduction The logging of large-diameter boreholes began in 1962, in the early stages of the Unite States AEC 's Underground Nuclear Testing Program, but was limited to modified caliper and temperature instruments. Other than that, logging data were gathered from 32-cm (12 1/2-in.) diameter exploratory boreholes, drilled at the location of, but prior to the large emplacement borehole. Standard logging instruments requiring large correction factors and the costs associated with the drilling of 32-cm (12 1/2 in.) exploratory boreholes gave impetus to the development of logging equipment especially designed for the large borehole environment. This equipment is now being used to insure the integrity of commercial mine shafts being constructed for haulage, access, and ventilation purposes. Boreholes as large as 304 cm (120 in. purposes. Boreholes as large as 304 cm (120 in. in diameter have been logged to depths of 1,830 M (6,000 ft). LARGE BOREHOLE LOGGING SERVICES The data acquired from logging can be divided into two categories:properties of the borehole andproperties of the formation. Borehole properties include:hole diameter and volume,borehole temperature,level and density of material in the annulus between the casing and the borehole wall during and after cementing,level and density of the material used inside the casing around the control cables for stemming to contain the nuclear event, andvarious repair operations in the borehole prior to using it for its designed purpose.