METHOD FOR GEOSTEERING HORIZONTAL AND DIRECTIONAL WELLS IN LOW-POWER FORMATIONS Russian patent published in 2020 - IPC G01V3/28 E21B47/228 E21B7/04 

FIELD: physics; mining.

SUBSTANCE: invention relates to geophysical exploration of geological exploration wells at alternating current during drilling and can be used for geosteering horizontal and directional wells in formations of reservoirs. Method comprises: geosteering of horizontal or directional well bores in low-power formations includes control of the process of drilling the well in the reservoir of the oil collector based on comparative analysis of distances to the boundary with beds of enclosing rocks, having contrasting properties as per specific resistivity relative to oil collector rocks. That is ensured by passing current pulses through the generator coil and recording the EMF of the transient processes in the receiving coil. Determination of the distances to the formation boundary is performed successively at two points of the well axis at a distance of not less than 1 m, during drilling as per values of time of extremums of EMF drop signals in the receiving coil. At the same time drilling direction is preserved when obtaining close values of distances obtained at two points on the well axis. Drilling direction is changed to obtain distances differing from each other. Drilling direction varies depending on the sign of the difference in distances.

EFFECT: technical result is improved accuracy of geosteering in reservoirs of low power.

1 cl, 3 dwg