Summary Borehole gravity gradiometry is becoming a more common technique to help in understanding the subsurface in the oil and gas industry. It can be combined with other techniques and well logs to form a very thorough interpretation of the target formations. The development and methodology of borehole gravity gradiometry and how it can be used in downhole applications is explained along with the advantages and disadvantages of this method. Introduction Gravity gradiometry has been a widely used technique for surface applications in the oil industry, but its use as a downhole tool provides a new way to investigate the borehole and allow for better resolution in projects like reservoir monitoring. Surface gravity gradiometry applications have been successful in monitoring reservoir activity with waterflooding operations, but borehole gravity gradiometry would overcome the depth-of-investigation limitations of surficial surveys (Neill, 2010). Downhole gradiometry also provides a deeper depth of investigation than nuclear measurements like gamma ray tools. History and Development The first underground measurements of gravity were completed in England by Airy (1865) which used pendulums to measure the vertical gravity gradient between the top and bottom of a vertical shaft (McCulloh, 1965). Gravity gradiometry was also the first geophysical survey that was applied to oil exploration. This was done in 1915 on the Egbell oil field in Slovakia, but was only a surficial survey using a torsion balance (Neill, 2010). A torsion balance is a pendulum designed by Hungarian physicist Baron Loránd Eötvös (1848-1919) that measures the density of the underlying rock. From 1915 to 1936 this technique was used rather extensively for geophysi... ... middle of paper ... ...ell Log Analysts (SPWLA) (1968): n. pag. Web. Neill, Francis. "Potential of Downhole Gravity Gradiometry for Reservoir Management."World Oil 231.1 (2010): n. pag. World Oil Online. Web. 5 Mar. 2014. Nekut, A. G. "Borehole Gravity Gradiometry." Geophysics 54.2 (1989): 225. SEG. Web. 17 Apr. 2014. Nind, Chris J.M., and Jeffery D. Macqueen. "The Borehole Gravity Meter: Development and Results." Kochi 2013 (n.d.): n. pag. Web. 5 Mar. 2014. Rim, Hyoungrea, and Yaoguo Li. "Single-hole Imaging Using Borehole Gravity Gradiometry." Geophysics 77.5 (2012): G67-76. SEG. Web. 17 Apr. 2014. Seigel, H. O., C. Nind, R. Lachapelle, M. Chouteau, and B. Giroux. "Development of a Borehole Gravity Meter for Mining Applications." Ground and Borehole Geophysical Methods: Proceedings of Exploration 07: Fifth Decennial International Conference on Mineral Exploration (2007): 1143-147. Web.
Marshak, S. (2009) Essentials of Geology, 3rd ed. New York: W.W. Norton & Company, ch. 11, p. 298-320.
The site visited on this day was informally known as the Bedrock Knob (NTS grid reference: 120 342). It is in an area where patches of limestone and exposed bedrock are common. The bedrock is part of the Preca...
Van Siclen, D. "The Houston Fault problem." Institute of Professional Geologists. Ed. 3rd Annual Meeting. Texas, 1967. p.9-31.
purpose we use this for is to drill wells into so that we may obtain the water that
A sampling port for measurement of the sediment concentration was located at 12.7 cm (5 in) from the bottom of the cylinder.
Eckel, Edwin B., ed. Nevada Test Site. Memoir 110 Boulder, CO: The Geological Society of America, 1968
remains in highest regards among seismologists, engineers and geologists. It is said to be a
Riley, C.M. "Lahars." Geological and Mining Engineering Sciences. Michigan Tech. Web. 6 Feb. 2010. .
Krajick, Kevin. "Tracking Myth to Geological Reality." American Association for the Advancement of Science. 310.5749 (2005): 762. Print. .
In Central Florida, sinkholes are a growing crisis. The causes of these sinkholes are numerous, but one of the main causes is because of Florida’s karst topography. According to the Oxford Dictionary, karst topography is “Landscape underlain by limestone that has been eroded by dissolution, producing ridges, towers, fissures, sinkholes, and other characteristic landforms.” Although sinkholes form unexpectedly without much warning, there are ways to prevent harm to people in Florida. Some ways to prevent sinkholes from causing harm and destruction is through methods of stabilization such as grouting, compaction grouting, underpinning, and remediation. Repairing a sinkhole can be terribly expensive, so choosing the right method is crucial when restoring sunken landscape.
In experiment 5, we are learning about density and specific gravity in measurements. Density is measured by mass divided by volume in order to get the ratio of the mass of an object to its volume. Specific gravity, on the other hand, is the density of a substance divided by the density of water and will cancel out the units in order to get a unitless measurement. Mass and Volume can be measured in two different ways, first mass can be calculated by directly placing it on the triple beam scale directly, or by weighing the difference. Volume can be calculated by displacement in the graduated cylinder or by calculating its dimensions. In this experiment, the objectives were to calculate the density of a solid by measuring its mass and volume,
Results from both the conductometric titration and gravimetric analysis were compared with other groups and mean values were established.
Most people don’t know the difference from a hanging wall and footwall. A footwall is the underlying block of a fault having an inclined fault plane. And a hanging wall is the mass of rock overlying a mineral deposit in a mine. (add citation from the book)
Coil, D., McKittrick, E., and Higman, B. (2010, December 16). Acid Mine Drainage. Ground Truth Trekking. Retrieved February 12, 2011, from http://www.groundtruthtrekking.org/Issues/MetalsMining/AcidMineDrainage.html
Waltham, Tony. "Sinking cities." Geology Today 18.3 (2002): 95+. Academic OneFile. Web. 08 Feb. 2014.