APPLICATION OF TURBULENT SENSOR IN STUDY OF MOVEMENT STATE OF LOWER PORTION OF DRILL STEM

The working mechanism of turbulent sensor was described and turbulent sensors used for measurement of movement state of lower portion of drill stem were designed and made. A series of simulating tests of movement of drill stem in a vertical wellbore was conducted on a testing rack. The test data were collected and treated by a computer. The following valuable conclusions were obtained:l. Non-contacting measuremcnts of simulat ed lateral movement of drill string can be realized by use of turbulent sensor; 2. The both clockwise and counterclockwise movement sections are present on a same drill string, but the clockwise is the more frequent; 3. There is a continuous point of the movement displacement but not of the stresses. The counterclockwise movement and the discontinuity of stresses are the important reasons of the failure of drill collars, centralizers and threads.