scholarly journals Effect of Partial Water Saturation on Attenuation Characteristics of Low Porosity Rocks

2010 ◽  
Vol 44 (2) ◽  
pp. 245-251 ◽  
Author(s):  
Tae-Min Oh ◽  
Tae-Hyuk Kwon ◽  
Gye-Chun Cho
Keyword(s):  
Water Saturation ◽  
Attenuation Characteristics ◽  
Partial Water ◽  
Low Porosity

Application of logging-while-drilling spectroscopy to evaluate volume of clay, grain density, and porosity in a low porosity, high temperature environment—offshore Western Australia

2014 ◽  
Vol 54 (2) ◽  
pp. 533
Author(s):  
Paolo Bartelucci ◽  
Mauro Firinu ◽  
Anthony Jones ◽  
Ping Yan
Keyword(s):  
High Temperature ◽  
Gamma Ray ◽  
Water Saturation ◽  
Dry Weight ◽  
Core Data ◽  
Low Salinity ◽  
Petrophysical Model ◽  
Logging While Drilling ◽  
Calcium Iron ◽  
Low Porosity

Formation evaluation in low porosity, low salinity, and high temperature reservoirs poses many challenges. The environment is hostile to many logging tools due to their temperature limits and there is greater uncertainty related to petrophysical parameters compared with conventional formations. Additionally, in low porosity and low salinity reservoirs, resistivity contrast between hydrocarbon and water filled rocks is often missing. This extended abstract presents a case study from offshore WA where a petrophysical model has been created with logging while drilling measurements including spectroscopy data to improve estimation of mineralogy, clay volume and porosity, thereby reducing saturation evaluation uncertainty. Spectroscopy measurements can be analysed to derive dry weight elemental concentrations of various elements such as silicon, calcium, iron, and sulfur. These concentrations have been subsequently used as input to compute a multi-mineral petrophysical model using a least squares inversion technique. We demonstrate that spectroscopy can be used independently to obtain an accurate volume of clay instead of gamma ray, spontaneous potential, or porosity logs. Moreover, matrix properties such as grain density, which enhance the accuracy of porosity estimation derived from bulk density, are also derived from spectroscopy dataset. Good agreement with core validates the petrophysical model. Also demonstrated is how the petrophysical model reduces the uncertainty in clay volume and porosity, from which more accurate water saturation can be derived in these tight reservoirs. Calibrating the spectroscopy information to core data allows the mineralogical and geological model to be extended to the intervals where core data are not available.

Seismic AVO variations related to partial water saturation during a pumping test

2007 ◽  
Author(s):  
Steven D. Sloan ◽  
Georgios P. Tsoflias ◽  
Don W. Steeples
Keyword(s):  
Water Saturation ◽  
Pumping Test ◽  
Partial Water

scholarly journals Depth characterization of shallow aquifers with seismic reflection, Part II—Prestack depth migration and field examples

Geophysics ◽  
2002 ◽  
Vol 67 (1) ◽  
pp. 98-109 ◽  
Author(s):  
John H. Bradford ◽  
D. S. Sawyer
Keyword(s):  
Seismic Reflection ◽  
Water Saturation ◽  
Compressional Wave ◽  
Unconsolidated Sediments ◽  
Prestack Depth Migration ◽  
Improve Image Quality ◽  
Depth Migration ◽  
Shallow Seismic ◽  
Partial Water

It is common in shallow seismic studies for the compressional‐wave velocity in unconsolidated sediments to increase by a factor of four or more at the transition from dry or partial water saturation to full saturation. Under these conditions, conventional NMO velocity analysis fails and leads to large depth and layer thickness estimates if the Dix equation is assumed valid. Prestack depth migration (PSDM) is a means of improving image accuracy. A comparison of PSDM with conventional NMO processing for three field examples from differing hydrogeologic environments illustrates that PSDM can significantly improve image quality and accuracy.

Laboratory study of partial water saturation in tight gas sandstone at seismic and ultrasonic frequencies

2014 ◽  
Author(s):  
X. Wei ◽  
S. X. Wang ◽  
J. G. Zhao ◽  
G. Y. Tang ◽  
H. J. Yin ◽  
...  
Keyword(s):  
Laboratory Study ◽  
Water Saturation ◽  
Tight Gas ◽  
Partial Water ◽  
Tight Gas Sandstone

scholarly journals Shallow seismic AVO variations related to partial water saturation during a pumping test

2007 ◽  
Vol 34 (22) ◽  
Author(s):  
Steven D. Sloan ◽  
Georgios P. Tsoflias ◽  
Don W. Steeples
Keyword(s):  
Water Saturation ◽  
Pumping Test ◽  
Shallow Seismic ◽  
Partial Water
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