METHOD FOR ASSESSING THE EFFICIENCY OF ACID TREATMENT OF CARBONATE FORMATIONS Russian patent published in 2023 - IPC E21B41/00 E21B43/27 

FIELD: oil production.

SUBSTANCE: invention can be used in the design of acid treatment of a productive carbonate formation. A method for evaluating the effectiveness of acid treatment of a carbonate reservoir is claimed, including conducting hydrodynamic studies, processing materials from well studies in transient modes by the method of pressure recovery before and after the event. A rank matrix is used in this acid treatment design. To build a matrix, an analysis of the performance of wells is done at the first stage during the injection of various volumes of the acid composition and the duration of its exposure to the reaction with the rock, taking into account the multiplicity of the event. The following are used as operational indicators of wells: increase in oil production rate after stimulation; additional oil production; the duration of the technological effect. Then, the well operation indicators for the conducted acid treatments are divided into groups depending on the change in the values of the injection rate parameters and the exposure time. The results of well operation indicators in the context of groups are averaged the optimal values of technological parameters for primary and repeated measures are revealed on the basis of their analysis. At the second stage, the analysis of the results of acid treatments is done based on changes in the productive and filtration properties of the formation, determined as a result of processing the hydrodynamic study data by the method of pressure recovery before and after the event. To do this, determine the dimensionless coefficient of change in well productivityβ_P, dimensionless coefficient of change in the permeability of the bottomhole formation zone for oilβ_PPP, dimensionless coefficient of change in the remote zone of the reservoir for oilβ_USP. At the third stage, a comprehensive assessment of the effectiveness of acid treatments is carried out using a rank system. Each of the performance indicators determined in the first and second stages is assigned a certain rank, and the quantity of numbers used in determining the rank corresponds to the quantity of selected groups. Next, the ranks are summed within the selected groups and the results are summarized in a single rank matrix.

EFFECT: improved quality of acid treatment design and, as a result, reduced technological and economic risks of subsoil users by determining the optimal technological parameters of the impact, namely the duration of the acid composition exposure to the reaction with the rock and the volume of the acid composition.

1 cl, 5 dwg