METHOD FOR DOWNHOLE DIRECTIONAL SURVEY AND DOWNHOLE SYSTEM FOR IMPLEMENTATION THEREOF Russian patent published in 2022 - IPC E21B47/02 

FIELD: measuring.

SUBSTANCE: invention relates to downhole directional surveying, in particular, to a method and system for downhole directional survey for the purpose of determining the spatial position of the wellbore with a ferroprobe inclinometer, including that in the process of drilling inclined and horizontal boreholes. The method includes pre-logging ground control implemented using two identical downhole tools, interconnected in series, wherein each tool comprises triads of accelerometric and ferroprobe sensors, sensitivity axes whereof match the axes of the bases of the first and second bodies of the downhole tools R_k1(x1,y1,z1) and R_k2(x2,y2,z2), respectively. Based on the results of the pre-logging control, a table of systems of inequalities characterising the sets of conditions of sensor operability is compiled. Further in the process of hoisting operations, the values of information signals of all accelerometric and ferroprobe sensors of both downhole tools are recorded, a comparative analysis of the recorded values with the table of systems of inequalities characterising the sets of conditions of sensor operability is performed, providing a possibility of identifying non-operating sensors, wherein, in case any of the accelerometric or ferroprobe sensors of one downhole tool fails, the sought zenith and sighting angles are determined based on the values of the second downhole tool.

EFFECT: increase in the hardware and information reliability of the downhole system and increase in the accuracy of measurements of the spatial position of the wellbore.

2 cl, 1 dwg