Study on clogging chemical injection lines in an oil well by emulsion breakers

Abstract

The principal objective of this research project is the evaluating and understanding why the clogging in the chemical injection line in an oil well, focused on demulsifiers, which are specialty chemicals widely used in the crude oil industry as emulsion breakers. In the chemical injection process, the physical properties of the fluids can be modified due to changes in pressure and temperature, leading to the production of solids particles, which can adhere to the pipelines, and consequently damaging the injection system. In order to find a solution, this problem needs to be understood. This research work is part of an EPIC developing investigation research (FAPESP/EQUINOR/UNICAMP) which was presented by Equinor as a problem that is already occurring in the Peregrino area. For that, hypotheses will be elaborate and evaluated considering valve mechanisms, chemical phase equilibrium, temperature and pressure gradients, and/or chemical compatibility, through a bench test that represents the normal operating conditions of the injection system. To test the elaborated hypotheses, some methodologies previously proposed in the literature for scale inhibitors test may be used, as well as new laboratory methods would be suggested. Vacuum filtration and product stability will be tested in order to assess the presence of any component that may cause line blockage, and to evaluate the fluid's demulsifiers incompatibility. Another methodology is the distillation test to evaluate the precipitation of solids after evaporation and the fluid properties as pH and acid concentration. Other proposed methods are the evaluation of inorganic materials using thermogravimetric analysis, energy dispersive spectroscopy (EDS), and dynamic scattering (DLS) with the aim to analyze the particle size present or produced in the fluid due to the storage period or incompatibility, and spectrometric analysis as FTIR. Moreover, a compatibility test through the aging test would help to determinethe properties of the materials and the influence on compounds that are part of the system, using accelerated weathering and rancimat equipment. Thus, the focus of this research proposal is to investigate why the clogging in the injection system could happen when the chemical injection is used. This through hypotheses elaboration, planning bench tests that would provide information about the problem, and correlating the bench results with the injection system. In that way, the information would help to propose new methodologies and techniques to use be with chemicals in the injection system. (AU)