METHOD OF DETERMINING THE FORMATION WATER SHARE IN THE PRODUCTION OF OIL WELLS Russian patent published in 2017 - IPC E21B47/10 

FIELD: oil and gas industry.

SUBSTANCE: crude oil from a well is accumulated in a vertical cylindrical tank, during a given time it is brought to the stratification state for stratification into formation water, water-oil mixture and crude oil with a low formation water content. In the process of draining the stratified crude oil from the vertical cylindrical container, the density of the formation water and oil is determined and, using their values, determine the mass share of the formation water in the crude oil. Crude oil is pumped from a vertical cylindrical tank along a liquid line with a mounted mass meter and moisture meter, during the drain cycle, the mass and density of stratified crude oil are measured, as well as the volume share of the formation water in the layer of crude oil with a low content of formation water. The values of mass and density are chosen at the times of the beginning and end of the draining cycle and the times of the beginning and the end of change in the measured value of stratified crude oil density. The mass share of formation water in crude oil is determined by the formula

,

where M is the value of crude oil mass, M_B - value of formation water mass, M_HB - value of mass of water-oil mixture and crude oil with low formation water content, - value of crude oil average density, - value of formation water average density, - value of water-oil mixture average density, - value of average density of crude oil with low formation water content, - value of average volume share of formation water in crude oil with a low formation water content, measured by the moister meter, whose values are calculated on the basis of measured values of mass, density and water share during the draining cycle.

EFFECT: increased accuracy of determining the content of formation water share in crude oil due to direct measurements of water-oil mixture density.