METHOD OF EARLY RECOGNITION OF ABNORMAL RESERVOIR PRESSURE ARP IN PROCESS OF BORING Russian patent published in 2008 - IPC E21B47/06 E21B45/00 

FIELD: oil and gas industry.

SUBSTANCE: invention refers to process of boring of oil and gas wells, particularly to methods of warning and prevention of problems and emergencies in boring process. The method consists in measuring the technological parameters on signals from surface primary converters-sensors, particularly in measuring mechanical rate of boring and in control over the mode of rock destruction at bottom hole, notably, surface, volumetric-fatigue or volumetric. At intervals of entering and further boring zones of ARP there is carried out continuous control over deepening bottom at one turn of a bit and over ratio of current rate of boring to corresponding rate at a previous slotting in similar periods of time from the commencement of slotting and at identical lithology of the cross-section. At the same time bottom is being deepened at one turn of the bit at more than 0.3...0.4 mm with simultaneous, stable in time for more, than 0.5 hour increase of mechanical rate as compared with the previous; then the value of differential pressure between the pressure of washing liquid at bottom and reservoir pressure is predicted within the range of 3...4 MPa. The value of differential pressure within the range of 0.5...1.0 MPa is predicted with deepening bottom at a turn of a bit for more, than 1/3 of medium height of teeth of cone bits or of teeth projection of cutting-shearing bits and simultaneous increasing the mechanical rate 2.5...3.0 times for clay rocks and 1.7...2.0 for the rest of rocks.

EFFECT: early recognition of prior-to-emergency situations while entering zone of abnormal reservoir pressures ARP and assessment of values of these pressures.