MWD-I Measurement While Drilling System is one of the most advanced technoli-

Giesis our cpmpany.

Working Principle

The downhole survey datd,suchsa inclination,azimuth,magnetic field,temperature

are measured ang coded by the survey electrical assembly(SEA).And then the mud

pulser generates positive mud pulse according to the coded survey data.When the

mud pulse come to the surface,the pressure transducer detdctsthem and send the

Electrical singals to the MWD Data Processor,which can complete the identification

of the singles and transmite it to the portable computer,such as a laptop.The soft-

ware installed in the computer will decode all the signals,and give out the survey data.

System Constitution

1. Downhole tools

Hang off Sub,flow sleeve module,mud pulse pluser,pulser driver module,battery module,survey electrical assembly (SEA) ,natural gamma-ray module

1. Surface equipments

 MWD Data Processor,rig floor display,pump pressure transducer,depth tracking

Unit,hook load tranducer,gamma printer

Specification

Inclination    ±0.1°

Azimuth      ±1.0°(INC>5°)

Tool face(magnetic/gravity)    ±1.0°

Temperature        0℃ ̴125℃

OD of pressure barrel  ɸ47.6mm

Max pressure of pressure barrel  ≤120MPa

Battery continuous working time  >200hours(varies with different working modes)

Features and benefits

1. Versatile in a wide range of operation environment

The motion of the pulser is driven by flushing with drilling mud,and the gap between

the restrictor and the stator is big enough,so all the nomal factor,such as depth,pu-

mp pressure,flow rate,mud granule,they do little effects to the pulser.Choose the right restrictor from three different sizes of restrictor,the pulser will give out the stable pressure pulses in different environments.

1. High precision

The sensor we used in the system are the best and had been well accepted by all the

oil field all over the world,the technologise we used,such as position error compens-

ation, are the same with the technologises that used in the spacecraft,and all these make the system has a high accuracy of measurement and high temperature

Stability.

1. Rapid data transmission

The puler works well when the width of pressure pulse varies from 0.5s to 2s for it work in a rotation mode. And it takes 7-30 seconds to refresh the tool face.

1. Long battery working time

The motions of the pulser are driven by mud.The electronmagnet valve inside the pulser only controls the rotation without contact of mud,and receive no force from the mud,so it expends little battery.We use quartz accelerometers in the SEA,which are accurate,need no warming time,can be powered on discontinuous.

1. Easy to maintenance

Only the restrictors,stators are exposed to erosion of mud.Other parts work in the lubricant without contact of mud,son the tool needs little maintenance,and which even can be done in the oil field.

1. Accommodation for additional geological parameter sensors

The system is hanging inside the collar,which makes it accommodate additional modules,such as resistivity logging module,gamma ray module,neutron logging module,etc.

7.Errosion resistant 

8.Wide range of rig floor display working temperature -45℃~60℃