The Borehole TeleviewerA New Logging Concept for Fracture Location and Other Types of Borehole Inspection

Abstract

Zemanek, J., Mobil Research and Development Corp. Caldwell, R.L. Mobil Research and Development Corp. Glenn Jr., E.E., SPE-AIME, Mobil Research and Development Corp. Holcomb, S.V., Mobil Research and Development Corp. Norton, L.J., Mobil Research and Development Corp. Straus, A.J.D., Mobil Research and Development Corp. The Borehole Televiewer logging tool takes an acoustic picture in the form of a well log, it invaluable for formation evaluation and borehole inspection. The log, which is run continuously, can define both induced and natural fractures, and can reveal vuggy porosity, the size and distribution of perforations in casing, and casing failures. Introduction A new and unique logging tool, called the Borehole Televiewer (BHTV), has been developed to inspect boreholes and to evaluate formations. Even though geologists and engineers have had only about 3 years' experience with the BHTV, the thinking of many of them has been radically influenced by the fascinating and revealing "log-picture" recorded with the tool. The BHTV fills a need for a logging tool that can produce a direct and descriptive record of the produce a direct and descriptive record of the physical properties of the borehole environment. Although physical properties of the borehole environment. Although primarily developed to evaluate fractured reservoirs, primarily developed to evaluate fractured reservoirs, the BHTV has been used successfully to solve a variety of problems related to formation evaluation and borehole inspection. Geologists and petroleum engineers have been confounded for many years by the problems of locating and evaluating fractures. Interpretation of the usual resistivity, acoustic or radioactivity logs, as well as the analysis of cores, for evaluation of fractured reservoirs is extremely difficult and often not definitive. This is understandable since analysis of cores from fractured formations has reported variously:low porosity,no effective permeability,lack of porosity,no effective permeability,lack of any matrix oil saturation andoil stains on fracture planes as the only indications of potential production. In recent years acoustic amplitude logs production. In recent years acoustic amplitude logs have been introduced and used with varying degrees of success to locate fractures. Conventional amplitude logs at best give only qualitative answers where quantitative ones are desired. The logs reveal nothing of the orientation of the fractures. In addition to these logs, various types of cameras, television, and rubber impression packers have been used for borehole inspection. (See Appendix.)The BHTV logging tool supplies both the quantitative and the orientation answers about fractures. The borehole can be filled with any homogeneous, gas-free liquid such as fresh water, saturated brine, crude oil or drilling muds. This tool takes an "acoustic picture" of the borehole wall. The resulting log is a picture" of the borehole wall. The resulting log is a representation of the borehole wall as if it were split vertically and laid flat. The log is oriented with respect to magnetic north. Any physical changes in the borehole wall are seen as changes in picture intensity. In this way, fractures, deformation or pits are reflected on the log. pits are reflected on the log. Tool Description The fundamental parts of the BHTV are shown in Fig. 1. A piezoelectric transducer probes the borehole wall with bursts of acoustic energy. A flux-gate magnetometer senses the earth's magnetic field and provides the means for determining the orientation of the log. JPT P. 762

Electrical texture characterization of dipmeter microresistivity signals using multifractal analysis

“…Indeed, DMS have a high sampling rate (about one measurement every 2.5 mm) and a relatively high vertical resolution (1-2 cm) [Schlumberger, 1970[Schlumberger, , 1986 compared to other wire line logs (e.g., gamma, gamma density, or neutron logs) that sample information from a relatively large volume (-20-100 cm in diameter) with vertical resolution of -15 cm. Together with the borehole televiewer [Zemanek et al, 1969] and the formation microscanner [Schlumberger, 1986] focusing on two-point correlations, e.g., rescaled range (R/S) analysis (see, e.g., chapter 8 of Feder [1988] for a review of R/S analysis), variograms, and power spectra [Hewett, 1986;Muller et al, 1992]. In this paper, we investigate a texture analysis method based on multifractal scaling.…”

Constraints on the Geometry and Fracturing of Hole 894G, Hess Deep, from Formation MicroScanner Logging Data

“…An older tool, the BoreHole Tele Viewer (Zemanek et al, 1970a;Zemanek et al, 1970b), turned out to be more suited to these studies (Newmark et al, 1984;Newmark et al, 1985b;Zoback et al, 1985;Morin et al, 1989) because it provides higher resolution measurement of the borehole shape and was used to confirm elongations inferred from caliper data (Plumb and Hickman, 1985).…”

Borehole Televiewer Data Analysis from the New Hebrides Island Arc: The State of Stress at Holes 829A and 831B

“…The BHTV was described first in detail by Zemanek et al (1969) and is used in borehole inspection for the detection of stress-induced wellbore breakouts, hydraulic fractures, and the analysis of structural features such as fractures and foliation. The BHTV employed on Leg 134 is a digital logging tool (slimhole BHTV, outer diameter 65 mm) that is able to operate in temperatures up to 120°C.…”

“…comm., 1992). Borehole breakouts are reliable stress indicators in terms of determining horizontal stress directions (e.g., Zemanek et al, 1970;Bell and Gough, 1979;Zoback et al, 1985;Blümling and Schneider, 1986) in the upper crust. In combination with rock strength measurements this method can also provide constraints on stress magnitudes (Moos and Zoback, 1990).…”