Measurement While Drilling (MWD) Petroleum Engineering

1. Measurement While Drilling

2. Including…….

3. Introduction

4. Objectives of MWD

5. Three types of telemetry systems are used:-
1. Positive Pulse System
2. Negative Pulse System
3. Continuous wave system

9. 1. Gamma-Ray Sensor
2. Resistivity Sensor
3. Temperature Sensor
4. Downhole WOB/ Torque
5. Turbine RPM
6. Standpipe Pressure Transducer

10. 1. Gamma-ray Sensor- Gamma-rays are emitted by radioactive
elements such as isotopes of potassium, thorium and uranium. With
this it is possible to identify shale zones
2. Resistivity Sensor:- Resistivity is a measure of the formation’s
resistance to the flow of electric current. The response from the
formation will depend on the fluid content. (Oil and gas act as
insulator)
3. Temperature Sensor:- Monitors the annulus mud temperature.
The sensing element may be a strip of platinum whose electrical
resistance changes with temperature.

11. 4. Downhole WOB/Torque:- Made by a system of sensitive strain
gauges mounted on the bit. The strain gauges will detect axial forces
for WOB and torsional forces for torque.
5. Turbine RPM:- consists of a 2-in. diameter probe that is placed
very close to the top of the rotating turbine shaft. As the shaft rotates,
an electric coil within the probe picks up voltage pulses due to the
magnets. By counting the number of pulses over a certain interval,
the turbine speed in rpm can be calculated.

12. 1. Directional Surveying
2. Formation Evaluation
3. Drilling Parameter