Gauges and well logging Overview IAEA International Atomic

Gauges and well logging Overview IAEA International Atomic Energy Agency Day 6 – Lecture 3

Objectives • To give an awareness of the use of radioactive sources in gauging equipment • To gain a basic understanding of how these gauges work IAEA 2

Content • What is a nuclear gauge ? • Applications of gauges in industry • Gamma gauges • transmission • Beta gauges • transmission and backscatter • Neutron gauges • Well logging IAEA 3

What is a Nuclear Gauge? • Device used in numerous industries, mostly in process control and quality control. Material Flow Shutter Control Detector Source Shutter (Closed) Shielding • Consists basically of a shielded radiation source and a radiation detector • The radiation interacts with the examined material before reaching the detector, supplying real-time data. IAEA 4

Applications of gauges in industry Quality Control • Density: rubber, oils, fabric, paper, etc • Thickness: paper, glass, steel, plastic films • Level: beverages, cooking oil Process Control • Density: cement, mud, liquids, chemical products • Level: vessels, silos, chemical products, minerals • Moisture: glass, cement, minerals IAEA 5

Applications of gauges in industry Quality control Film Thickness Beverage Level IAEA Paper Thickness Oil Level 6

Applications of gauges in industry Process Control Mud Flow IAEA Mineral Weight Mineral Level Liquid Flow 7

Types of nuclear gauge Gauges can be categorised by their mode of • operation • transmission • backscatter • type of radioactive source used • Gamma • Beta • Neutron IAEA 8

Types of nuclear gauge Transmission: the detector measures the amount of radiation that passes through the examined material IAEA 9

Types of nuclear gauge Backscatter: the detector is placed on the same side as the source, measuring the amount of scattered radiation IAEA 10

Types of nuclear gauge • Gamma • Beta • Neutron IAEA 11

Gamma gauges • • Density gauge Level gauge All operate in transmission mode Sources used • caesium-137 • cobalt-60 • americium-241 IAEA 12

Density gauge source: 1 GBq Cs-137 Typical Detector Source For a known thickness of material, the density can be deduced by comparing the radiation signal at the detector with and without the material in the beam IAEA 13

Point level gauge Typical source: 10 GBq Cs-137 High level alarm Sources Detectors Low level alarm IAEA 14

Point level gauges IAEA 15

Liquid fill height gauge Accept Source Detector Typical Drinks can or bottle source: 3. 7 GBq Am-241 Reject IAEA 16

Liquid fill height gauge IAEA 17

Beta gauges • • thickness gauge (transmission) coating thickness gauge (transmission) film thickness gauge (backscatter) Sources used • krypton-85 (encapsulated gas) • strontium-90 (foil source) • promethium-147 (foil source) IAEA 18

Beta thickness gauge source Typical sources: 3. 7 GBq Pm-147 11. 1 GBq Kr-85 web detector IAEA 19

Beta thickness gauge Can be used to measure: paint, oil, lubricating films, plastic, enamel, ceramic and phosphate coatings on metals and some nonmetals IAEA 20

Beta thickness gauge IAEA 21

Beta coating thickness gauge Source 1 Source 2 coating web Detector 1 IAEA Detector 2 Typical source: 37 GBq Kr-85 22

Beta backscatter gauge Typical sources: 200 MBq Pm-147, Tl-204 GM counter Source Metal coating Substrate Thicker the coating, the more backscatter IAEA 23

Beta backscatter gauge IAEA 24

Neutron gauges • • hydrocarbon detection gauge moisture content gauge usually operate in backscatter mode Sources used Øamericium-241/beryllium Øplutonium-238/beryllium IAEA 25

Moisture Gauging using Neutrons Typical source 1. 85 GBq Am/Be Detector Neutron shield High hydrogen concentration Neutron source Low hydrogen concentration IAEA 26

Neutron soil moisture gauge IAEA 27

Nuclear Density Gauge Typical sources: 1. 85 GBq Am-241/Be 370 MBq Cs-137 Neutron source moisture measurement Am-241/Be gamma source density measurement IAEA Cs-137 28

Nuclear density gauge IAEA 29

Well Logging Operations and Equipment • Well logging • Drill to Stop • Measurement or Logging While Drilling • Borehole logging • Sources used • caesium-137 (gamma), typically 40 GBq • americium-241 / beryllium (neutron), typically 110 GBq IAEA 30

Drill-to-Stop Well Logging Operation Well Logging operation that requires all drilling operations to cease and requires that parts of the drilling apparatus are removed to provide access to the well bore. The well logging tool is then lowered into the well bore to obtain information. IAEA 31

Drill-to-Stop Well Logging Operation Well Logging tools without sources at storage facility Well Logging tools without sources stored in transport vehicle IAEA 32

Measurement While Drilling (MWD) IAEA 33

Measurement while Drilling (MWD) Well Logging operations that occur during the drilling of the well bore and do not require that the drill stem or other equipment be removed from the well. This type of operation requires that the well logging tool contains one or more sealed sources and be located above the drilling stem to obtain information through mud telemetry communications. IAEA 34

MWD - Neutron Sub Radioactive Source Port Detectors IAEA 35

MWD – Gamma Sub Radioactive Source Port Detectors IAEA 36

Geological borehole logging Geological logging is used to investigate the geological make-up of an area by lowering test tools into a borehole. The picture shows a logging tool containing a neutron source. IAEA 37

Summary • Overview of the types of nuclear gauges found in the workplace • Brief description of well logging equipment and process IAEA 38