RMBAKER LLC employs industry standard geophysical methodologies as part of comprehensive subsurface testing and investigation studies. We offer surface and borehole geophysical methods with ground penetrating radar, electrical resistivity imaging and a full suite of well logging tools available in-house. We specialize in the identification and characterization of sinkholes and sinkhole forming processes in Florida, however our state-of-the-art geophysical and data presentation capabilities can be extended to a variety of other applications. Feel free to contact Rob Baker at RMBAKER LLC to discuss your project needs, with no obligation. Our geophysical work products are integrated with advanced GPS and GIS techniques, for a world class field survey and map product. We also provide technical support for global mineral exploration programs and local mining operations. We provide a comprehensive research program to evaluate mineral, oil, and gas resources within a geographic information system. Our reports are informative but concise, with high quality CAD and graphics images to aid with the visualization of site characteristics. Our products are available in GIS friendly formats, depending on your specific project needs. |
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Borehole Geophysics - Well Logging
- State-of-the-art well logging tools and hydraulic draw-works mounted within a 16 foot custom trailer.
- Logging depth range of 0 to 4500 feet; well diameters 4 inches or greater.
- Complete suite of geophysical logging tools from Robertson Geologging (USA), Inc.
- Video logging tools from Aries CCV Engineering; video to 4500 feet; VHS tape or DVD products.
- Redundant video recording simultaneously to VHS tape and DVR HDD.
- Field printed logs in 300dpi grayscale using a Printrex 843 DL/G thermal printer.
- Logs provided in PDF and LAS format.
***View a summary table of tools, capabilities and limitations***
Our services are offered 7 days a week, 24 hours a day!
We offer straightforward pricing with no surprises after the work is done-
Contact us for a verbal price quotation or formal bid.
Logging Tools available:
- Normal 8"/16"/32"/64" resistivities (Electric log w/ natural gamma)
- SP, SPR and natural gamma (Electric log w/ natural gamma)
- Natural gamma can be measured by two separate tools in counts-per-second
- Dual induction (20" & 32" spacings) w/ natural gamma
- Fluid temperature w/differential
- Fluid conductivity w/differential and normalized to 25 degrees C
- Caliper (3-arm, 4" to 87" diameters)
- Sonic Log, borehole compensated w/ full waveform and VDL
- Cement bond log w/ VDL
- Acoustic televiewer-sonic reflection imaging
- Dual-view video inspection camera (4"+ well diameters)
- Impeller flowmeter w/ caliper normalized percent flow log
- Gas/fluid sampler (1-liter sealed chamber)
Specialized logs:
- Annular volume calculation-Log showing plot of borehole volume after casing insertion, based on reamed hole caliper data. Nominal bit size and casing size also shown.
- Quantitative flow calculations-Series of logs with flowmeter RPM data normalized to line speed and borehole caliper data. Percentage flow can be shown as function of average flowmeter response, or idealized flow below the pump.
Ground Penetrating Radar (GPR)
- In-house: Mala Geosciences Ramac X3M radar system with 250 MHz and 500 MHz antennas
- Capability to rent: 100 MHz and 800 MHz antennas
- Rugged cart for rough terrain surveys on foot or towed by a 4-wheel ATV
- Sub-meter GPS positioning in real time during survey work
- GPR and GPS data integrated in a geographic information system (GIS) map product
Our forensic investigations are smaller scale studies performed at residential properties and small commercial sites. Field maps are hand drawn and rectified to a grid painted on the ground surface.
Larger property investigations and pre-development studies are normally performed by towing the GPR antenna behind a 4-whell ATV. A high resolution GPS antenna is mounted to the GPR cart for sub-meter accuracy in locating the transects. We collect GPS and GPR data simultanously, and then after corrections to the GPS data use a proprietary algorithm to merge the two datasets.
RMBAKER LLC GPR and GPS data manipulation routines enable extremely accurate mapping and modeling of geological and cultural features noted by the geophysical testing.
GPR example 1:
GPR example 2:
GPR example 3:
GPR example 4:
Resistivity - Electrical Resistivity Imaging (ERI)
- Iris Instruments, Inc. Syscal Kid Switch 24, or Syscal Pro Switch 96 (rented)
- Kid 24 electrode system with a maximum spacing of 5 meters (approx. 16 feet)
- Pro 96 electrode system with a maximum spacing of 5 meters (approx. 16 feet)
- Effective geoelectrical profiling to depths of 65 feet (Kid) or 200 feet (Pro)
- ERI and GPS data integrated in a geographic information system (GIS) map product
- 3D rendering of ERI bitmap images
- We have successfully completed 100 acre scale resistivity mapping projects using the OhmMapper from Geometrics, Inc.
The ERI image below shows a thin veneer of sands atop a thick sequence of limestone. The limestone was both soft/weathered and hard/competent, with confirmed deep vertical fracture systems.
2D ERI images can be mapped as earth slices in a 3D environment. In this case the ERI study investigated the continuity of a clayey confining unit shown by the "cooler" blue colors.
The image below shows a capacitively-coupled resistivity profile using the Geometrics, Inc. Ohm-Mapper in a thinly mantled karstic terrain. The Ohm-mapper basically operates as a towed array that measures a dipole-dipole section continuously.
The Ohm-Mapper can be used to survey very large areas and then build GIS models of relative sinkhole risk. The orange areas in the map below indicate areas at risk as interpreted from the Ohm-Mapper dataset. We generated 28 miles of profiling data for approximately 120 acres of property with limited accessibility.
Geological Hazards Mapping
- Common geological and man-made hazards in Florida are: sinkholes, shrink-swell clays, peat and organic soils, naturally buried debris, construction debris, etc.
- We employ a combination of GIS datasets, visual reconnaisance and geophysical testing to identify and map geological hazards.
- In-house geophysical methods include GPR, ERI and borehole geophysics; we can perform a wide range of tests using rented equipment, such as microgravity, electromagnetics, capacitively-coupled resistivity, etc.
- Soil borings and laboratory testing are an important part of suspected hazard identification and confirmation.
- Geological hazards mapping is presented in a geographic information system (GIS) map product.
In the example image below we used electrical resistivity profiling to identify buried muck zones. The interpreted anomalies were confirmed with soil borings. A collection of approximately 17 transects mapped the discontinuous presence of buried muck.
GPR profiling can be used to map subsurface karstic features. These features can be extrapolated from the GPR transect so that they coalesce with similar anomalies on adjacent transects. In the example image shown below, the green areas represented karstic valleys with internal drainage and the potential for subsidence of structures if developed upon.
Sinkhole Risk Assessments
- RMBAKER LLC offers sinkhole risk assessments based on a localized relative scale or absolute scale expanded to the State of Florida as a whole.
- Our risk assessments are expert-style opinions that incorporate site or regional specific criteria that can vary dramatically across Florida.
- We combine advanced GIS techniques with integrated geophysical and soils testing.
- We characterize a site based upon its physiographic (geomorphologic), hydrogeologic, and geologic properties, with special attention to karst geomorphology.
Sinkhole Report Reviews-Second Opinions
- RMBAKER LLC offers second opinions of insurance investigations of sinkholes.
- We can provide a desktop review only, a desktop review with a site visit, or a comprehensive review that includes our own geophysical and soils testing.
- We examine each case in the context of regional geological and hydrogeological conditions, and apply those concepts to the site specific data and form a professional opinion as to the probability of sinkhole-related subsidence.
Some important concepts addressed by our report reviews:
We believe that the geophysical testing is paramount, and that high quality comprehensive geophysical testing provides a working framework for all other site testing. Geophysical results must be properly integrated in the final analysis.
We employ a series of sinkhole models based on the published literature and fundamental geological and hydrogeological concepts. Each site is characterized in terms of the types of sinkholes present and the mechanisms we believe are the driving force for subsidence.
Sinkhole Expertise
- RMBAKER LLC offers
subcontracted surface geophysical testing for insurance
claim investigations. We offer the following basic
packages with some variations as needed:
- GPR only - interior and exterior GPR survey with a single antenna frequency.
- GPR + ERI - GPR survey combined with two resistivity profiles typically performed on both sides of the residence/structure along the long axis of the property, or where access is readily available. This combined approach with optimized resistivity is very popular, and provides the best site assessment value.
- ERI only - This approach presumes the ineffectiveness of GPR due to soil limitations at the site.
- RMBAKER LLC offers specialized geological assessments of the presence of a sinkhole for property insurance claims. We utilize in-house geophysical testing capabilities with subcontracted SPT and CPT drilling services.
- We are experts in the detection and mapping of sinkholes and other geo-hazards.
- We can provide an authoritative exploration of the subsurface conditions at a site to determine what, if any, soil conditions may have caused property damage. Our exploration approach would naturally be directed primarily toward identification of geological hazards.
- We examine each site in the context of regional geological and hydrogeological conditions, and apply those concepts as well as fundamental sinkhole models to the site specific data and form a professional opinion as to the probability of sinkhole-related subsidence.
Please note that we do not provide engineering services, although we can recommend capable and reputable engineering firms. Our sinkhole studies are geological in nature, and do not address structural issues or sinkhole remediation.