Much has been written about the need to recover residual oil remaining in the depths of the oilfields being developed. The challenge has become a large and attractive target for enhanced oil recovery methods (EOR), and methods of treating bottomhole zones (BHZT). When addressing social and economic challenges faced by the region and the country it is considered that one of the acceptable options to replenish hydrocarbons stocks and maintain their production suggests further development of new techniques and effective use of proven methods. The effect of the methods is determined by a variety of processes, some of which can often be ignored, but still are crucial for their success and effectiveness. Thus, using various reservoir stimulation methods and trying to solve some specific problems, it is necessary to exclude unintended consequences for further effective implementation of other subsequent technological processes [1, 2, 3].
Complications in the development and exploitation of oil fields can be caused not only by the initial geological and physical conditions, but also by the impact of a large number of technologies applied in reservoir stimulation, crude oil gathering, transportation, and treatment of oil and water. It is difficult to predict the consequences of cross technology interference at the following, subsequent, stages. Even small amounts of chemicals, carried to the bottom of the well, can cause negative consequences. The paper presents assessment of the chemicals influence when treating a reservoir formation and its fluids in order to prevent negative effects at various stages of upstream and midstream.
Scientists and experts found that no polyacrylamide when using the demulsifier makes it possible to separate 96.8% of water. But even when there are relatively inert chemicals in concentrations of 0.1%, only 32.2% of water can be separated. In all cases it is necessary to eliminate the loss of sedimentation stability of oil and its breaking down, since there is a huge amount of hydrocarbons lost in the form of precipitation, sediments and intermediate layers. As the main parameter to determine the changes in crude oil properties it has been proposed to measure changes in absorption spectra properties (recalculated for the light absorption coefficient of oil) before and after exposure to chemicals.
This interaction has been simulated in the laboratory, and the results have been quantified using multivariate analysis. Studies were conducted with photocolorimeter in the laboratory of Oil and Gas Fields Department in Almetyevsk State Oil Institute. The experiments were carried out using samples of crude oil from Devonian deposits, the Romashkino oilfield. Chemicals with different targeting were studied. Experiments have shown that the light absorbance coefficients of oil samples at different wavelengths have selective sensitivity to interference. Moreover, various grades of chemicals have had different degrees of impact on a hydrocarbon system both in the laboratory simulation conditions and under field conditions. Mathematical statistics applied has made it possible to identify wavelengths that are not sensitive to the chemicals studied, but reliably indicate changes in oil composition and properties. The experiments have also revealed the joint effect of factors.
The practical value of the work is its ability to prevent many negative processes that can lead to a variety of problems due to violations in oil production techniques, transportation, and treatment of produced crude oil; huge losses of hydrocarbons that can become unnecessary ballast in the system. The economic effect of implementing research results is in the opportunity to bring the use of reservoir stimulation techniques to the optimum, increase the overhaul period for the wells, reduce the number of workovers, and improve processing of the produced oil.
