METHOD FOR ISOLATING BRINE-SATURATED INTERVALS IN THE GEOLOGICAL SECTION OF WELLS OF OIL AND GAS CONDENSATE FIELDS ACCORDING TO THE DATA OF MULTIMETHOD MULTI-PROBE NEUTRON LOGGING Russian patent published in 2021 - IPC G01V5/10 G01V11/00 

FIELD: mining industry.

SUBSTANCE: invention relates to neutron logging methods for determining brine-saturated intervals in the geological section of cased oil and gas wells, separation of brine-containing and brine-absorbing intervals relative to salt layers, as well as isolation of intervals with brine in cement stone. The method allows to solve the problem of separation of brine containing intervals during the construction of wells for planning and carrying out a set of measures to prevent brine occurrences in the well, which is the cause of a man-made accident. As a result of measurements of spectrometric neutron-gamma-ray logging - NGL and neutron-neutron logging by thermal neutrons - NNL, salt layers are first isolated by an abnormal increase in the readings of large probes - NNLlp in the absence of an increase in the readings of small probes - NNLsp against the background of the readings of these probes in a water-saturated reservoir (WSR), then against the background of the obtained readings, layers saturated with brine are isolated, by a sharp drop in the readings of the NGLlp and NNLlp probes and a sharp increase in the NNL decrement curve compared to the readings of these probes in the WSR. The presence of brine-absorbing intervals is judged by their position under rock salt layers with a less sharp drop in the readings of NGLlp and NNLlp than in the case of a brine-containing formation and a less sharp increase in the NNL decrement curve compared to their readings in the WSR. The presence of brine absorption intervals in the cavities of cement stone is judged by the drop in the readings of NGLsp and NNLsp at a constant value of the NNL decrement compared to their readings in the WSR.

EFFECT: expansion of the functionality of the complex of neutron methods for the separation of the cut intervals of cased oil and gas wells containing brine, the separation of brine-containing intervals and salt intervals, the separation of brine-absorbing intervals, as well as intervals with brine in cement stone.

1 cl, 4 dwg