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Acoustic televiewer log images of natural fractures and bedding planes in the Toa Baja Borehole, Puerto Rico
Author(s) -
Paillet Frederick L.,
Goldberg David
Publication year - 1991
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/91gl00407
Subject(s) - borehole , geology , bedding , drilling , lost circulation , seismology , bed , sonic logging , well logging , echelon formation , petrology , paleontology , geophysics , drilling fluid , fault (geology) , mechanical engineering , physics , anisotropy , quantum mechanics , horticulture , engineering , biology
Although borehole conditions made acoustic televiewer logging difficult in the Toa Baja borehole, more than 180 meters of continuous, acceptable quality televiewer logs were obtained in the intervals from 730 to 880 meters and from 2,515 to 2,675 meters in depth, indicating the presence of fractures that appear to be open in situ. Most of the largest, possibly open fractures in these intervals are either nearly parallel to directions given by the dipmeter log and may represent solution openings or minor washouts along bedding planes, or dip steeply to the south or southwest across bedding. The televiewer log confirms the presence of an apparently open set of fractures near 867 meters in depth, where circulation was lost during drilling, and in the interval from 2,600 to 2,650 meters in depth, where the temperature log indicates anomalous heat flow in the surrounding formation.