IMPROVING ACIDIZING IN THE COLLECTORS CHARACTERIZED BY DIFFERENT CARBONATE CONTENT (ON THE EXAMPLE OF OIL FIELDS OF PERM KRAI)

Abstract

The relevance of the work is caused by the fact that the technological parameters of the acid treatment, such as holding time in the reservoir and the volume of composition, significantly affect the result of the geological and technical measure. According to many experts, it is necessary to study the issue of the need for an acid stage in the reservoir and its duration in the technological process of processing. The specific volume of acid is determined by various factors, such as rock composition, the bottomhole zone properties, the desired depth of acid penetration into the reservoir, etc. The main aim of the study is to assess the impact of the technological parameters of acid treatments on the effectiveness of geological and technical measure in the oil fields of the Perm region. The method of study is the laboratory experiments using a device for determining the carbonate content of rocks – the carbonatomer KM-04M, filtration units with simulation of formation conditions of UIP-5VG and AFS-300, as well as the units of microfocus fluoroscopy. The results. An acid exposure was performed using two compositions to determine the return permeability and X-ray tomographic studies for different «calcite-dolomite-insoluble residue» components of the core samples from deposits in the Perm region. X-ray tomographic experiments were performed twice on each core sample: before and after the acid treatment. The conditions for the effective use of acidic formulations in the oil fields under consideration were selected based on the results of filtration and X-ray tomographic studies. Summation of all the research results allowed developing recommendations for optimizing the technological parameters of acid treatments at the considered production target. The use of X-ray tomography made it possible to distinguish cases for which, as a result of acid exposure, an increase in the volume of void space is observed with a decrease in permeability. This fact will allow further work to improve the formulation of acid compositions and technologies for their use.

Keywords

• acid treatments
• carbonate reservoirs
• filtration research
• tomography studies
• coefficient of permeability recovery
• technological parameters
• holding time in reservoir
• amount of injected composition
• technological efficiency