INFLUENCE OF THE COMPOSITION OF BIOPOLYMER DRILLING FLUIDS ON THE QUALITY OF EXPOSURE OF PRODUCTIVE LAYERS OF THE WESTERN SIBERIA

Abstract

Relevance of the study is caused by the need to improve the existing formulations of water-based drilling fluids for the primary opening of the productive reservoir of the Western Siberia. The use of such drilling fluids for the initial opening of oil reservoirs leads to an irreversible decrease in the design flow rate of the well. Application of stimulation operations (hydraulic fracturing) is not possible due to the presence of a complex geological structure of productive horizons (oil reservoirs of low thickness, the proximity of bottom water). To assess the impact of flushing fluids on the reservoir properties, it is necessary to conduct laboratory tests simulating reservoir conditions on a core to identify the reasons for the decrease in permeability. Purpose: to assess the effect of various formulations of water-based flushing fluids on the reservoir properties of productive reservoirs. Objects: core material - fine- and medium-grained homogeneous gray sandstone with signs of hydrocarbons, water-based primary drilling fluids. Methods: study of the degree of influence of various opening drilling fluids on the reservoir properties of a productive reservoir; assess of the values of the recovery factor of the core permeability in thermobaric conditions, as close as possible to the reservoir ones. Results. The authors assessed the influence of flushing fluids of primary opening on the change in the filtration-capacity properties of the core material collected from the Western Siberia; determined the reasons for the decrease in the permeability recovery factor; carried out a number of studies to assess the rheological and technological parameters of drilling fluids.