METHOD FOR MONITORING WATER ENCROACHMENT OF BOREHOLES AND UNIT FOR IMPLEMENTATION THEREOF Russian patent published in 2023 - IPC E21B41/00 E21B47/10 G01N27/403 G01N33/18 

FIELD: gas industry.

SUBSTANCE: group of inventions relates to the gas industry and can be used for monitoring the development of gas and gas condensate deposits. In particular, claimed is a method for monitoring the water encroachment of boreholes, including continuous determination of the degree of mineralisation of associated water carried over from the boreholes and calculation of the proportion of reservoir water. Herewith, a resistive sensor is precalibrated, wherein the calibration consists in measuring the electrical resistance and temperature of saline solutions of predetermined mineralisation in laboratory conditions using a sealed conductometric cell modelling the measurement conditions in the wellhead equipment. Saline solutions and oil-in-water emulsions with different content of reservoir water are used as calibration solutions. For each calibration solution, at least five modes evenly arranged in the expected temperature range are set using a thermostat. The calibration data are used to perform numerical selection of approximation coefficients A, B, C, D by minimising the non-linear functional by the Nelder–Meade method. After calibration, the resistive sensor is installed on the lower generatrix of the pipeline in a cylindrical recess with a depth of 8 mm and an internal diameter of 20 mm, acting both as a sample collector and a measuring cell, wherein the straight line connecting the electrodes is oriented perpendicular to the direction of the gas-liquid flow. Measurements are then taken of the temperature and electrical resistance of the associated fluid with predetermined discreteness. The obtained data are then processed, wherein the processing consists in filtering the peak values associated with switching the ranges of measurement of the electrical resistance, and the value of the mode of electrical resistance for the predetermined period of time is calculated, mineralisation degree is calculated, and the genesis of associated water is diagnosed. According to the mineralisation and the data of technical fluid application, the associated water is diagnosed in the following order: water with a mineralisation degree less than or equal to 1 g/l is 100% condensation water; if no interventions associated with the injection of process fluids into the borehole have been performed, then the water carried over constitutes a mixture of condensation and reservoir water, wherein the proportion of reservoir water is determined by the formula: wherein S_pl is the proportion of reservoir water in the sample; M, M_con, M_pl is the mineralisation degree of the sample of associated, condensation, and reservoir water, respectively, g/l. Also claimed is a unit for the implementation of the method.

EFFECT: higher efficiency of operation monitoring of the water encroachment of gas and gas condensate boreholes due to the online diagnostics of the genesis of associated fluid.

3 cl, 9 dwg