METHOD OF DETERMINATION OF CURRENT BOTTOM-HOLE HYDRODYNAMIC PRESSURE IN COURSE OF WELL DRILLING Russian patent published in 2000 - IPC

FIELD: oil and gas producing industry, wells construction, particularly, methods of determination of current bottom-hole hydrodynamic pressure in course of well drilling with its horizontal completion in highly drained sand reservoirs of low thickness. SUBSTANCE: method includes lowering into well of assembly for measuring of pressure values with mud circulation at flow rate assumed during well drilling. Novelty consists in that lowered into well seating device is downhole instrument of PELENG telesystem and in the course of drilling, presence of sand interlayers in drilled section is determined by variation of values of gamma pulses of natural radioactivity in drilled section with the help of gamma logging transducer installed in downhole instrument. Value of pressure in mud circulation in downhole motor and drill bit is determined by differential pressure pickup installed in downhole instrument. Pressure value in drill string with mud circulation is calculated. Mud pump pressure value with mud circulation is fixed by pressure gage installed on drilling rig or by drilling control station, and obtained data are used for calculation of pressure value in annular space. Then, pressure value of mud at given depth is calculated. Downhole current hydrodynamic pressure in course of drilling is determined by mathematical expression. EFFECT: reduced cost of determination of current hydrodynamic pressure with high efficiency of its determination.