METHOD OF EVALUATION OF PHASE PERMEABILITY PROFILE IN OIL AND GAS PRODUCTION WELLS Russian patent published in 2019 - IPC E21B47/10 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the field of oil industry and is intended for determination of permeability of productive intervals opening low-permeability reservoirs. According to the method, distribution of diameters of pore channels in the analyzed interval is preliminary determined according to the core material. Thereafter, the tested active well is brought to a stable operating mode and field-geophysical measurements are carried out in the analyzed interval of the well opened reservoir with a spectral noise meter at the process selection mode by recording an acoustic signal at discrete depths with a step of discreteness in depth, selected depending on sectionalization and the required resolution of the obtained permeability profile, with a given measurement time at each point, then at each measurement point, determining amplitude-frequency characteristic of acoustic emission signals in a given frequency range, selecting, in the obtained amplitude-frequency spectrum, peak frequencies with reference to the previously obtained distribution of diameters of porous channels on the core material, after which phase permeability values kj (mD) are determined at each measurement point for each characteristic diameter of pore channels by the following formula:

,

where μ is viscosity [cP], n, ρ are tuning parameters selected based on the principle of analogies (proximity of the estimated core sample to one of the previously studied core collections), F is the frequency recorded by the instrument and tied to the corresponding pore diameter [kHz], D is the dominant diameter of the pore channels based on the mercury porometry results [mcm]. Then, permeability values at each measurement point are used to construct a profile of phase permeability of the analyzed collector interval.

EFFECT: obtaining a depth profile of reliable values of phase permeabilities suitable for use in a hydrodynamic model of the formation, from the depth of the analyzed section in the production well with ultra-low permeabilities of reservoirs (including with permeability of thickness below 1 mD); providing correlation of acoustic emission signals as per well section with distribution of filtration channels.

1 cl, 4 dwg