The problems of improving the technology aimed at reducing the volume of associated water production and increasing oil recovery from partially flooded deposits is very urgent. This paper discusses topical problems of further effective development of depleted oil fields to increase their final oil recovery on the example of the oil field in Western Kazakhstan. The methods of bottomhole zone treatment implement a deflecting effect on filtration flows. Therefore, this method includes a wide range of geological and technical measures: down-spacing; water production restraining; conformance control of injectivity profiles; forced production; all types of mechanical, thermochemical and thermal technologies. Geological and statistical models are proposed for diagnosing wells for a premature increase of water production using factor analysis calculations for base production and Hall plots. The degree of temperature influence of the primary components of the compounds on the rheology, filtration characteristics, and stability of inverted emulsions was determined. The classification of oil loss factors was carried out based on the results of downhole analysis and oil production losses were determined. Geological and statistical models for well diagnostics for premature increase in water production were built using factor analysis calculations for base production and Hall plots.