Borehole geophysics has proven to be an indispensable tool for our clients in coal exploration, mineral mining, coal seam gas exploration and scientific research to name just a few. It is an incredible value-adding tool to confirm target depths, characterise overburden, assess dipping angles and much, much more.
Groundsearch uses state of the art combination tools from Century Geophysical Corporation to maximise the information gathered from the hole, while maintaining usability and the convenience to transport the equipment to operate from nearly anywhere (and over the years our clients have occasionally pushed this “anywhere” claim to extremes! – See “Our Projects”) Our most popular tools are listed here, but we can get in a tool to suit almost any endeavour very quickly.
With the backing of a huge amount of experience in exploration projects all over NZ, and a comprehensive support structure, we can manage your borehole geophysics effectively and efficiently. Email us for more information.
Borehole Tools
9239 Dual Density Sonde – Coal Combination Tool
The Series 9239, Compensated Density logging tool uses the two focused density detectors to compute borehole compensated density real time while logging. No post processing required to produce CDL bulk density. Additionally, the tool also records natural gamma, caliper , medium guard resistivity, and borehole temperature.
The 9239 is a very well proven, diverse and reliable tool which is ideally suited for coal exploration as well as a variety of other applications. It delineates coal seams with fantastic accuracy, and can operate inside or outside the water column, and even inside or outside drill rods or casing.
Acoustic Scanner
The Acoustic Televiewer takes an oriented “picture” of the borehole using high-resolution sound waves. This acoustic picture is displayed in both amplitude and travel time. This information is used to detect bedding planes, fractures, and other hole anomalies without the need to have clear fluid filling the boreholes.
The televiewer digitizes 256 measurements around the borehole at each high-resolution sample interval (.005 meters/.02 feet). This data is oriented to North and displayed real-time while logging using the Visual Compu-Log software. Analysis includes color adjustment, fracture dip and strike determination, and classification of anomaly. It allows information to be displayed on the graphical screen, plot, and in report format. Optionally, the tool can be equipped with a natural gamma sensor.
Full Wave Sonic
The Full Wave Sonic tool contains a single transmitter and dual receiver to record formation travel times. The full wave form data is also recorded simultaneously, along with near and far travel times, borehole-compensated delta time, calculated sonic porosity, receiver gains, near/far amplitudes and natural gamma. The sonic or acoustic log uses the basic principle of sound waves traveling through a media. The Century sonic system uses a single transmitter and dual receiver system for recording the travel times of the formation. The receivers are spaced approximately 2 and 3 feet, from the transmitter. Therefore, a 0.3 m (1 ft.) calculation can be made to measure this interval transit time.
9410 Dipmeter
The Dipmeter tool is a formation strike and dip directional probe primarily used in mining and environmental logging applications. Additionally, the tool also records natural gamma, X-Y calipers, and borehole deviation is computed from the slant angle and bearing measurements calculated from the inclinometer and magnetometer sensors. To ensure accurate strike and dip measurements in small-diameter holes, special care should be taken when calibrating the calipers to maximize their accuracy.The image to the right shows a set of dipmeter data with “tadpoles” giving dip and dip direction of the bedding structures. The bed boundary is picked from the current logs. The boundary is then cross-correlated between each pad data and merged to give the dip of the best “plane ” through this data.
