Department of Rock Mass Geophysics

The Department of Rock Mass Geophysics is an organisational unit of The Research and Development Centre for Mining of Chemical Raw Materials “CHEMKOP” Ltd. The Department is the only organisation in Poland that offers echometric surveying of caverns filled with brine, or gas or liquid hydrocarbons. Such survey projects have been conducted since 1974, and the relevant equipment has been regularly modernised, with the improvement of surveying techniques. Nearly 6,500 surveys have been completed until today.

The majority of surveys are based on the use of the CHEMKOP Echosonda (echo sounder), fitted with a tilting head. We also carry out surveys with the use of a large-diameter cavernometer, an inclinometer, and a gamma probe.

Measurement taking, reading recording, and digital data storage are conducted with the use of our in-house software.

Good knowledge of our customers’ needs and outstanding skills and expertise of our surveyors contribute to the accuracy and reliability of our surveys. Our Survey Reports provide our customers with data in a comprehensible manner. The availability of our surveyor teams assures conducting syrveys, within a short lead time.

The Department workers are suitably educated and experienced. Their engineering solutions are based on long-term practice and regularly developed theoretical considerations. Those are good grounds for continuous improvement of our survey devices, measurement methods, and interpretation techniques, as well as user-friendly software.

High quality of our equipment and modern measurement and interpretation methodology, together with high competence of our surveyors, allow us for the provision of professional services to the businesses that are involved with mineral extraction, applying solution mining technologies, as well as underground gas or liquid hydrocarbon storage, or material deposition. Our expertise and skills have been successfully tested outside Poland as well, in such countries as Bosnia and Herzegovina, Brazil, Germany, Iraq, Slovakia, and Turkey.

Measuring equipment

Echo sounder with a tilting head

Echo sounder with a rotating and tilting probe head is the basic element of the CHEMKOP echometric system. The system also includes a logging cable, fixed to the surveyors’ vehicle, a control panel, with all the measurement controls, a digital transceiver, and a computer for signal recording and data storage.
The CHEMKOP echo sounder allows for carrying out echometric surveys in caverns, filled with such liquids as brine, liquid hydrocarbons, or gas, under the pressure of up to 24 MPa.
The echo sounder probe can reach out to those sections of the cavern that are “invisible” in horizontal profiling, in particular in the areas of the cavern ceiling, bottom, and side branches.
Technical parameters of the echo sounder with a tilting head:

Depth of survey	up to 2,000 m
Ultrasound signal transducer frequency	f₀ = 47 kHz; horizontal and vertical
Horizontal transducer beam width in brine	V: 5,5° ; H: 38,5°
Structural material	Stainless steel and brass
Magnetic orientation accuracy of the electronic compass	N = ± 1°
Maximum range in brine	up to 180 m
Rotation range	from 0° to 360°, continuous
Tilt range	from -90° to +90°
Distance measurement accuracy	± 0,2 m
Diameter	65 / 70 mm
Length	2,8 m
Weight	35 kg
Scope of temperature	from -5°C to +80°C

The survey system complies with the ATEX94/9/WE Standard and ensures explosion safety

Large-diameter cavernometer

The well cavernometer is a downhole tool designed to measure the borehole diameter. Owing to its innovative design, the CHEMKOP cavernometer can measure distances with four independent arms, each with the reach of up to 1 m. The symmetrically arranged arms can measure the well diameters of up to 2 m.

Cavernometer
Parameter	Value
Probe weight	116 kg
Operating temperature	from 0° to 60°
Max. operating pressure	24 MPa
Probe length	3,116.5 mm
Probe diameter	139 mm
Max. diameter to be measured	2,000 mm
Min. diameter to be measured	139 mm
Power supply, Voltage, min. – max.	36 to 75 V DC
Power supply, Current	ca. 20 mA, depending on voltage
Transmission rate	9,600 b/s
Type of transmission	differential signalling, complying with RS-485

Inclinometr

The inclinometer is a downhole tool designed to measure the angle of well deflection from plumb. The purpose of profiling is to establish the spatial orientation of the well axis.
The probe deflection and azimuth angles, obtained at a given depth, will allow for visualising the course of the well inside the rock mass.

Inclinometer
Parameter	Value
System weight, including: - inclinometer - ballast	60 kg 18,6 kg 40 kg
Operating temperature	from 0° to 60°
Max. operating pressure	24 MPa
Recording point	561 mm from the top connector edge
System length, including: - inclinometer - ballast	2,511.5 mm 1,206 mm 1,389.5 mm
Min. diameter of the measurement opening, with a centring device	200 mm
Min. diameter of the measurement opening, without a centring device	100 mm
System diameter, without a centring device	70 mm
System diameter, with a centring device	448 mm
Power supply, Voltage, min. – max.	from 36 to 75 V DC
Power supply, Current	ca. 20 mA, depending on voltage
Transmission rate	9,600 b/s
Type of transmission	differential signalling, complying with RS-485

Gamma probe

The gamma probe is designed to measure natural gamma radiation in boreholes and wells and is mainly used to determine the changes occurring in the rock mass lithology and depth correlation. The survey records the number of the radioactive material decay counts, in the form of the number of pulses per unit of time.
The gamma photons cause flashes of light from scintillation crystals, and those are amplified by a photomultiplier installed in the probe.

Gamma Probe
Parameter	Value
System weight, including: - gamma probe - terminal	25 kg 23 kg 2 kg
Operating temperature	from 0° to 60°
Max. operating pressure	24 MPa
Recording point	298 mm from the top connector edge
System length, including: - gamma probe - terminal	1,113 mm 1,060 mm 140 mm
Min. diameter of the measurement opening, with a centring device	150 mm
Min. diameter of the measurement opening, without a centring device	80 mm
System diameter, without a centring device	70 mm
System diameter, with a centring device	448 mm
Power supply, Voltage, min. – max.	from 36 to 75 V DC
Power supply, Current	ca. 20 mA, depending on voltage
Transmission rate	9,600 b/s
Type of transmission	differential signalling, complying with RS-485
Range of measured energy	from 2,000 keV/min.

Company’s fleet of vehicles

The Department’s fleet of vehicles used on site depends on the size of service order and the geographical location of our customers. We possess surveyors’ cars equipped with logging cables and the equipment required for the control of all the CHEMKOP echo sounder operations, signal recording, and handling other echo sounders. Our fleet also includes vehicles for the transportation of surveying equipment and accessories to the site. The vehicles can operate at several survey sites at the same time. They ensure high mobility and flexibility of our surveyor teams. We regularly replace our vehicles to comply with ever growing requirements.

The idea of measurement

The cavern shape and size surveys, using the CHEMKOP echo sounder, are based on the phenomenon of ultrasound reflection from the cavern walls. The measurement of time from sending a signal by the probe to the signal’s return to the probe allows for the measurement of the distance between the probe and the point of reflection (when the wave velocity is known).

Multiple repetitions of measurements taken at various depths and at various probe-head’s angles of azimuth and elevation allow for the identification of cavern shapes and sizes. That survey method ensures determination of the actual cavern shapes in each of its sections or branches.

Cavern surveys include the following:

• Ultrasound wave velocity profiling in the medium that fills the cavern
• Temperature profiling along the well axis
• Vertical profiling at the selected azimuth
• Horizontal profiling at measurement steps
• Surveying the cavern’s side branches, ceiling, and floor, using a tilting probe head
• Determination of the pipe-shoe depth

When taking measurements at a particular depth and with a particular probe tilt setting, a full rotation is made around the probe axis, with continuous ultrasound signal recording.

Our cavern survey methodology takes into account the customer’s requirements concerning the measurement interval and step. The number of steps can be increased in the course of a survey, depending on the cavern shape complexity. Owing to our surveyors’ long-term experience, proper selection of survey parameters can considerably improve the accuracy of measurements.

Measurement handling, as well as digital signal recording and storage, are controlled by our in-house software. The survey data collected by the CHEMKOP echo sounder are recorded in the form of raw echograms that contain full wave images that can be processed afterwards.

We guarantee the completion of all the survey process stages, with due diligence, to obtain accurate and reliable results.