Innovative foam-acid technology of bottom-hole area for intensification of oil production from carbonate reservoirs in PJSC "Tatneft"

The development of new technologies of selective acid-foam stimulation the near-wellbore zone of formation isan urgent task to intensification the processes of oil production. The article is devoted to laboratory tests foam-acidcomposition of the new formulation, the study of patterns of changes of physico-chemical, rheological and technological characteristics of the foam-acid composition (density, viscosity, foaming, stability, dispersion, wettability, the kinetics of dissolution-heat, recoveryof Fe+3, the compatibility with the oil and formation water), depending on the concentration of ingredients, time, temperature, and shear rate ratios ofthe component. The studies developed foam-acid composition with controlled physicochemical properties adapted to geological and physical conditions of deposits PJSC "Tatneft".
Materials and methods
Research of foam-acid compounds. It was conducted pilot testing of a new acid processing technology to generatefoam-acid at the bottom of the well, with working innovative ways of self-regulatory operations to stimulate the flow of oil inheterogeneous porous fractured reservoirs by covering a greater layer thickness and deep chemical exposure.
Results
According to the results of research on the period of pilot projects designed to guide the technology SCR of carbonate formation with the new formulation of the PCB, which includes various technological options for delivering gas generating solution and acid composition in the treatment interval. As part of ODA in the current year it is planned to carry outworks on five wells, four of which with an open horizontal barrel length of 100 to300 m.
Сonclusions
1. The formula has been developedfoam-acid composition with improved and adjustable physical and chemical properties;
2. Foam-acid composition due to the foam structure and the presence of surfactants has a low speed of reaction with carbonate rocks and performs basic transportation function - delivery of the acidic solution with a surfactant into the formation;
3. High wetting ability, adjustableviscosity and structural-mechanical properties provide the selectivity and uniformity of processing and maximum utilization of acidic composition;
4. Foam-acid condition is characterized by polydisperse, with a predominance of small and middle cellated structures whose dimensions are comparablewith the geometric characteristics of microcracks in natural carbonate reservoir;
5. Education DCC is a mixture of two components: a gas-generating solution and the acidic composition in a specific ratio; reference borehole option is delivery via two hydraulicchannels with the formation of the PCB at the bottom of the well followed by injection into the reservoir;
6. It is assumed in the course of ODA to optimize the technological aspects of the batch injection foam-acid or other fluids, with the aim of obtaining the planned levels of oil production.