METHOD FOR ASSESSING OIL SATURATION OF RESERVOIRS IN CASED OIL AND GAS AND OIL AND GAS CONDENSATE WELLS WITH HIGH MINERALIZATION OF FORMATION WATER BY MULTI-METHOD MULTI-PROBE NEUTRON LOGGING - MMNL Russian patent published in 2024 - IPC G01V5/10 

FIELD: oil, gas and coke-chemical industry.

SUBSTANCE: invention relates to the oil and gas industry and is intended for assessing oil saturation (OS) (content of liquid hydrocarbons) in reservoirs with high mineralization of formation water in cased oil and gas and oil and gas condensate wells with application of different depth modifications of neutron research methods. Disclosed is a method for assessing oil saturation of reservoirs in cased oil and gas and oil and gas condensate wells with high mineralization of formation water using multi-method multi-probe neutron logging — MMNL. Implementation of the method is carried out using an integrated neutron-neutron logging tool, which includes two probes of neutron-neutron logging by thermal neutrons — 2NNL-T, providing measurement in the well of thermal neutron flux intensities — J_SPt on a small probe and a large probe — J_LPt, and three probes of neutron-neutron logging on epithermal neutrons – 3NNL-Et, in the process of which neutron flux intensities are measured at small J_SPet, medium J_MPet and large J_LPet probes at different distances from the casing wall. Using the measurement data, using the attached formulas, the OS coefficient — K_os in the oil-saturated formation is calculated separately for the near, middle and far zones and the volumetric oil saturation — K_os×K_fn.

EFFECT: improving reliability of OS estimation under conditions of deposit operation at three-phase saturation of reservoirs (gas, oil, highly mineralized formation water), at high mineralization of formation water (more than 100–150 g/l) and with porosity less than 10–15%.

5 cl, 2 dwg