Application of Geophysical Logging to Groundwater Studies in Southeastern Saskatchewan

1972 ◽  
Vol 9 (1) ◽  
pp. 78-94 ◽  
Author(s):  
J. H. Dyck ◽  
W. S. Keys ◽  
W. A. Meneley
Keyword(s):  
Epithermal Neutron ◽  
Single Point ◽  
Good Resolution ◽  
Spontaneous Potential ◽  
Gravel Beds ◽  
Natural Gamma ◽  
Water Well ◽  
Resistivity Logs ◽  
Routine Basis ◽  
Sand And Gravel

Single-point resistance and spontaneous potential logs in fresh-water filled rotary-drilled test-holes provide data useful in geohydrologic studies in Saskatchewan. These geophysical logs are made by many of the water well drilling contractors in Saskatchewan on a routine basis. The logs provide good resolution of various lithologic units and provide data required to estimate the salinity of water in sand beds prior to constructing a well.Caliper logging offers a potentially useful method for evaluating hole conditions and the effect of drilling techniques on the formation in completion zones. The casing collar locator log run in a previously constructed well near Estevan demonstrates that this device can provide an accurate and objective measurement of the position and length of each joint of casing, the position of the screen assembly, and the location of screened and blanked intervals within the screen assembly. This tool should find general application in water well construction and maintenance practice.The neutron-epithermal neutron log provides a method of measuring the porosity of sand and gravel beds. The response of the gamma log is similar to that of the spontaneous potential log and the neutron-epithermal neutron log deflects in a fashion similar to the resistance and resistivity logs. Nuclear logs offer the advantage that they can be run in cased or uncased boreholes which may be filled with any type of fluid. They require more complicated and expensive instrumentation and slow-speed logging to obtain the required resolution. The normal resistivity logs offer the possibility of determining the concentration of dissolved solids in the formation water. The gamma-gamma log is a poor alternative to the natural gamma and neutron log for stratigraphic correlations.

Geological and geophysical studies of buried valleys and their fills near Elora and Rockwood, Ontario

1994 ◽  
Vol 31 (12) ◽  
pp. 1838-1848 ◽  
Author(s):  
J. P. Greenhouse ◽  
P. F. Karrow
Keyword(s):  
Epithermal Neutron ◽  
Single Point ◽  
Low Frequency ◽  
Last Interglacial ◽  
Sedimentary Sequences ◽  
Transient Electromagnetic ◽  
Quaternary Sequences ◽  
Natural Gamma ◽  
Geophysical Logs ◽  
Well Data

Buried bedrock valleys are of economic interest for groundwater and engineering studies, and of scientific interest for the sedimentary sequences they may contain. Two buried valleys, about 60 m deep, north and northeast of Guelph, Ontario, are tributary to the major Dundas Valley southwest of Guelph. Located initially from water well data, their locations and geometry were refined with surface geophysics, including very low frequency resistivity, terrain conductivity, resistivity, transient electromagnetic, gravity, and seismic methods. Useful data are obtained roughly in proportion to cost. Cored and rotary holes in the two valleys were followed by geophysical downhole logging with normal electric, spontaneous potential, single-point resistance, calliper, neutron – epithermal neutron, gamma–gamma, and natural gamma methods. Cores revealed multi-till sequences in the upper parts of the holes and, together with geophysical logs and their interpreted electrofacies, indicate the presence of underlying uniform, pollen-bearing (pine and spruce dominate) lacustrine fills. These fills and the buried valleys containing them are interpreted to be perhaps as old as the last interglacial. Buried valleys are fruitful targets for the discovery of older Quaternary sequences.

Estimation of in situ hydrocarbon saturation of porous rocks from borehole measurements of spontaneous potential

Geophysics ◽  
2020 ◽  
Vol 85 (6) ◽  
pp. D199-D217
Author(s):  
Joshua Bautista-Anguiano ◽  
Carlos Torres-Verdín
Keyword(s):  
Drilling Mud ◽  
Porous Rocks ◽  
Spontaneous Potential ◽  
The Matrix ◽  
Resistivity Logs ◽  
Petrophysical Model ◽  
Hydrocarbon Saturation ◽  
The Difference ◽  
Mud Filtrate

It has been previously shown that Nernst’s equation is not reliable for the interpretation of spontaneous potential (SP) measurements acquired in hydrocarbon-bearing rocks. We have examined whether the difference between borehole SP measurements and Nernst-equation predictions could be used to estimate in situ hydrocarbon saturation of porous rocks. For this purpose, a new petrophysical model and a mechanistic finite-difference algorithm for simulating SP borehole measurements in the presence of mud-filtrate invasion are used to establish the limits of detectability of hydrocarbon saturation using only SP logs. We find that the optimal conditions for the detection of hydrocarbon saturation from SP borehole measurements are when (1) capillary forces dominate the process of mud-filtrate invasion, (2) the matrix-pore interface region, known as the electrical double layer, has a relevant impact in the diffusion of counterions, and (3) the electrolyte concentration of drilling mud is greater than that of formation water. We also determine why high values of the endpoint of the water relative permeability favor the detection of hydrocarbon-saturated rocks with the SP log. Using measurements acquired in three key wells within a mature and active hydrocarbon field, three blind tests find that our petrophysical model together with the mechanistic SP simulation algorithm enable the estimation of hydrocarbon saturation from SP borehole measurements without the need for resistivity logs or porosity calculations. The estimation is reliable when the volumetric concentration of shale is negligible, the pore network structure is constant throughout the reservoir, and radial invasion profiles are similar to those observed in the calibration key wells.

Organic detritus particles: Initiation of motion criteria on sand and gravel beds

1983 ◽  
Vol 19 (6) ◽  
pp. 1627-1631 ◽  
Author(s):  
John S. Fisher ◽  
Ben L. Sill ◽  
Douglas F. Clark
Keyword(s):  
Organic Detritus ◽  
Gravel Beds ◽  
Sand And Gravel

Bed configuration and microscale processes in alluvial channels

1993 ◽  
Vol 17 (2) ◽  
pp. 123-136 ◽  
Author(s):  
André Robert
Keyword(s):  
Probabilistic Approach ◽  
Field Measurements ◽  
Bedload Transport ◽  
Transport Processes ◽  
Coarse Grained ◽  
Small Scale ◽  
Alluvial Channels ◽  
Gravel Beds ◽  
Sand And Gravel ◽  
Bed Material

Numerous recent studies on fluvial processes, both in Canada and internationally, have focused on small-scale phenomena. Investigations on the characterization of surface roughness in coarse-grained channels and its links with flow resistance and sediment transport processes have been a dominant field of research. Closely related is a second major area of investigation on turbulent flow structures in boundary layers over both sand and gravel beds and their relations with the transport of bed material. Phenomena potentially related to 'bursting' have been shown to control bedload transport processes and the concentration of sediment in suspension. Detailed investigations have also been conducted on the links between flow turbulence, bed material movement, and bed morphology at channel junctions. Finally, selective entrainment and transport of individual coarse particles have been studied from field measurements and laboratory experi ments. Emphasis has been put on bed microtopography, surface structure and texture, and on a probabilistic approach to bedload transport.

Inference of lithologic distributions in an alluvial aquifer using airborne transient electromagnetic surveys

Geophysics ◽  
2010 ◽  
Vol 75 (4) ◽  
pp. WA149-WA161 ◽  
Author(s):  
Jesse E. Dickinson ◽  
D. R. Pool ◽  
R. W. Groom ◽  
L. J. Davis
Keyword(s):  
Alluvial Aquifer ◽  
Coarse Grained ◽  
Resistivity Structure ◽  
One Dimensional ◽  
Fine Grained ◽  
Transient Electromagnetic ◽  
San Pedro ◽  
Resistivity Logs ◽  
Sand And Gravel ◽  
San Pedro Basin

An airborne transient electromagnetic (TEM) survey was completed in the Upper San Pedro Basin in southeastern Arizona to map resistivity distributions within the alluvial aquifer. This investigation evaluated the utility of 1D vertical resistivity models of the TEM data to infer lithologic distributions in an alluvial aquifer. Comparisons of the resistivity values and layers in the 1D resistivity models of airborne TEM data to 1D resistivity models of ground TEM data, borehole resistivity logs, and lithologic descriptions in drill logs indicated that the airborne TEM identified thick conductive fine-grained sediments that result in semiconfined groundwater conditions. One-dimensional models of ground-based TEM surveys and subsurface lithology at three sites were used to determine starting models and constraints to invert airborne TEM data using a constrained Marquardt-styleunderparameterized method. A maximum structural resolution of six layers underlain by a half-space was determined from the resistivity structure of the 1D models of the ground TEM data. The 1D resistivity models of the airborne TEM data compared well with the control data to depths of approximately [Formula: see text] in areas of thick conductive silt and clay and to depths of [Formula: see text] in areas of resistive sand and gravel. Comparison of a 3D interpolation of the 1D resistivity models to drill logs indicated resistive (mean of [Formula: see text]) coarse-grained sediments along basin margins and conductive (mean of [Formula: see text]) fine-grained sediments at the basin center. Extents of hydrologically significant thick silt and clay were well mapped by the 1D resistivity models of airborne TEM data. Areas of uncertain lithology remain below conductive fine-grained sediments where the 1D resistivity structure is not resolved: in areas where multiple lithologies have similar resistivity values and in areas of high salinity.

Geotechnical applications of electrical borehole logging in southern Saskatchewan

1980 ◽  
Vol 17 (4) ◽  
pp. 545-558 ◽  
Author(s):  
E. Karl Sauer
Keyword(s):  
Data Base ◽  
Data Storage ◽  
Single Point ◽  
Stratigraphic Correlation ◽  
Borehole Data ◽  
Spontaneous Potential ◽  
Borehole Logging ◽  
Field Supervision ◽  
Sample Recovery ◽  
Observation Wells

Single point resistance and spontaneous potential geophysical borehole logging is shown to be a valuable supplement to conventional coring methods in geotechnical site exploration. A continuous graphical record of the sediments is obtained without gaps caused by sample recovery problems. The log provides an effective capability for stratigraphic correlation. The technique is also shown to be of value as a format for a borehole data base and for use in instrumentation design such as piezometers and observation wells. The technique has limitations such as drift and maintenance difficulties but these can be overcome by adequate field supervision. Over 7000 testholes have been logged successfully and are in data storage in Saskatchewan.

LOG EVALUATION OF NONMETALLIC MINERAL DEPOSITS

Geophysics ◽  
1970 ◽  
Vol 35 (1) ◽  
pp. 124-142 ◽  
Author(s):  
M. P. Tixier ◽  
R. P. Alger
Keyword(s):  
Gamma Ray ◽  
Mineral Deposits ◽  
Good Resolution ◽  
Coal Beds ◽  
Resistivity Logs ◽  
Bulk Volume ◽  
Neutron Porosity ◽  
Commercially Important ◽  
Sulfur Deposits ◽  
Sonic Logs

Well logs can be used to locate and evaluate deposits of various commercially important minerals. It is only necessary that the mineral of interest represent a significant fraction of the formation bulk volume, and that it exhibit characterizing properties measurable by logs. Because modern logging methods measure electrical, density, acoustic, radioactivity, and certain nuclear characteristics of formations, they may be used to identify many minerals. For evaluation of sulfur deposits, either density or sonic logs provide good resolution when compared with porosity computed from neutron or resistivity logs. Trona beds are identified by a sonic reading of approximately 65 μsec/ft, neutron porosity index of about 40 percent, low natural radioactivity, and pronounced hole enlargement. Gamma‐ray logs provide important information in the location, identification, and evaluation of potash mineral deposits. Neutron, sonic, and density logs, in various combinations, augment the gamma‐ray data in such studies. Coal beds are characterized by high resistivities, and by high apparent porosities on sonic, neutron, and density logs. Density logs are particularly suited for evaluation of yield from oil shales. In all such explorations for nonmetallic mineral deposits, well‐logging methods provide a fast, detailed, and economical reconnaissance of the entire length of drilled hole. Results compare well with core assays.

scholarly journals Hydrogeomorphic effects on bedload scour in bull char (Salvelinus confluentus) spawning habitat, western Washington, USA

2010 ◽  
Vol 67 (4) ◽  
pp. 626-640 ◽  
Author(s):  
Jeffrey G. Shellberg ◽  
Susan M. Bolton ◽  
David R. Montgomery
Keyword(s):  
Woody Debris ◽  
Main Channel ◽  
Spawning Habitat ◽  
Stream Power ◽  
Salvelinus Confluentus ◽  
Channel Change ◽  
Gravel Beds ◽  
Side Channels ◽  
Western Washington ◽  
Sand And Gravel

We investigated the vulnerability of fall-spawned bull char ( Salvelinus confluentus ) embryos to redd scour during winter rain and rain-on-snow flood discharges in western Washington, USA. It was hypothesized that the magnitude of bedload scour at bull char redds is reduced by the provision and selection of stable refugia habitat controlled by local-, reach-, or subcatchment-scale variables such as hydraulic habitat unit and channel type. Bedload scour and channel change were measured using 96 scour monitors and 34 elevational transects in three catchments over 2 to 4 years. Scour to cited egg burial depths of bull char did not commence until discharge typically exceeded the 2-year recurrence interval. At a local scale, scour varied significantly among side channel, protected main channel, and unprotected main channel redd sites. Unprotected gravel patches in simplified channel types with moderate gradients were most susceptible to deep scour, especially if coupled with the transient supply and storage of sand and gravel from mass wasting. Partially transport-limited reaches had reduced scour due to lower stream power and armored gravel beds. Complex spawning habitat (i.e., with abundant large woody debris and side channels) was important in providing refuge from deep scour and in buffering embryos against inhospitable hydrologic or sediment regimes.

Combined simulation and inversion of SP and resistivity logs for the estimation of connate-water resistivity and Archie’s cementation exponent

Geophysics ◽  
2008 ◽  
Vol 73 (3) ◽  
pp. E107-E114 ◽  
Author(s):  
Jesús M. Salazar ◽  
Gong Li Wang ◽  
Carlos Torres-Verdín ◽  
Hee Jae Lee
Keyword(s):  
Water Saturation ◽  
Estimation Method ◽  
Inversion Method ◽  
Initial Water ◽  
Data Set ◽  
Spontaneous Potential ◽  
Connate Water ◽  
Resistivity Logs ◽  
Combined Simulation ◽  
Water Resistivity

Knowledge of initial water saturation is necessary to estimate original hydrocarbon in place. A reliable assessment of this petrophysical property is possible when rock-core measurements of Archie’s parameters, such as saturation exponent [Formula: see text] and cementation exponent [Formula: see text], are available. In addition, chemical analysis of formation water is necessary to measure connate-water resistivity [Formula: see text]. Such measurements are seldom available in most applications; if they are available, their reliability may be questionable. We describe a new inversion method to estimate [Formula: see text] and Archie’s cementation exponent from the combined use of borehole spontaneous-potential (SP) and raw array-induction resistivity measurements acquired in water-bearing depth intervals. Combined inversion of resistivity and SP measurements is performed assuming a piston-like invasion profile. In so doing, the reservoiris divided into petrophysical layers to account for vertical heterogeneities. Inversion products are values of invaded and virgin formation resistivity, radius of invasion, and static spontaneous potential (SSP). Connate-water resistivity is calculated by assuming membrane and diffusion potentials as the main contributors to the SSP. Archie’s or dual-water equations enable the estimation of [Formula: see text]. The new combined estimation method has been successfully applied to a data set acquired in a clastic formation. Data were acquired in a high permeability and moderately high-salt-concentration reservoir. Values of [Formula: see text] and [Formula: see text] yielded by the inversion are consistent with those obtained with a traditional interpretation method, thereby confirming the reliability of the estimation. The method is an efficient, rigorous alternative to conventional interpretation techniques for performing petrophysical analysis of exploratory and appraisal wells wherein rock-core measurements may not be available.

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