Changes

[[file:applying-gravity-in-petroleum-exploration_fig15-17.png|300px|thumb|{{figure number|6}}Example of a borehole gravity tool that succeeded where conventional open-hole and cased-hole logging methods had failed. After Van Popta et al.<ref name=ch15r12>van Popta, J., J. M. T. Heywood, S. J. Adams, and D. R. Bostock, 1990, Use of borehole gravimetry for reservoir characterisation and fluid saturation monitoring: Expanded Abstracts, SPE Europec 90 conference, p. 151–160. Use of time-lapsed borehole gravity logging to monitor fluid movement away from the borehole.</ref> Copyright: SPE.]]

[[file:applying-gravity-in-petroleum-exploration_fig15-17.png|300px|thumb|{{figure number|6}}Example of a borehole gravity tool that succeeded where conventional open-hole and cased-hole logging methods had failed. After Van Popta et al.<ref name=ch15r12>van Popta, J., J. M. T. Heywood, S. J. Adams, and D. R. Bostock, 1990, Use of borehole gravimetry for reservoir characterisation and fluid saturation monitoring: Expanded Abstracts, SPE Europec 90 conference, p. 151–160. Use of time-lapsed borehole gravity logging to monitor fluid movement away from the borehole.</ref> Copyright: SPE.]]

[[:file:applying-gravity-in-petroleum-exploration_fig15-17.png|Figure 6]] shows an example of a borehole gravity tool that succeeded where conventional open-hole and cased-hole logging methods had failed. In the upper part of the log, the gamma-gamma density log underestimates the gas saturation by about 15%. In the lower part of the log, wash-out zones are dominant, affecting the gamma-gamma log but not the BHGM log. Over these intervals, borehole gravity gives a more reliable and higher overall density measurement. The reservoir was fractured at [[length::853 m]], and a normally tight reservoir started to produce gas. The second BHGM logging run shows the lower density of the fractured, gas-filled producing interval. Shallower than [[length::810 m]], both gamma-gamma and BHGM logs agree. The borehole gravity tool was used to measure secondary gas saturation in a fractured limestone reservoir.

[[:file:applying-gravity-in-petroleum-exploration_fig15-17.png|Figure 6]] shows an example of a borehole gravity tool that succeeded where conventional open-hole and cased-hole logging methods had failed. In the upper part of the log, the gamma-gamma density log underestimates the gas saturation by about 15%. In the lower part of the log, wash-out zones are dominant, affecting the gamma-gamma log but not the BHGM log. Over these intervals, borehole gravity gives a more reliable and higher overall density measurement. The reservoir was fractured at [[length::853 m]], and a normally tight reservoir started to produce gas. The second BHGM logging run shows the lower density of the fractured, gas-filled producing interval. Shallower than [[length::810 m]], both gamma-gamma and BHGM logs agree. The borehole gravity tool was used to measure secondary gas saturation in a fractured [[limestone]] reservoir.

==See also==

==See also==