Chemicals have been injected into the downhole of the oil wells in an attempt to ensure efficient production.
This measure is a usual oilfield strategy to improve the characteristics of crudes or deal with some flow
assurance problems, such as emulsions, scales, paraffin or asphaltenes deposition, etc. To overcome these
issues, downhole chemical injection systems (DHCI) have been installed in production facilities, in which the
injection of chemicals is controlled by chemical injection valves (CIVs). In this work, it was investigated the
possible causes of the failure of four commercial CIVs from demulsifier injection lines installed in heavy oil
production systems. The analysis consisted of disassembling the CIVs and analyzing their internal elements,
seeking the cause of the failure. A solid material (clogging) was found in some specific parts of the CIVs, which
could be the main cause of the CIVs’ failure. Solubility tests indicated a polar or apolar characteristic,
depending on the CIV. After the analysis, the CIVs were cleaned and reassembled, and tests in a high-pressure
line indicated that all of them got back to work properly. These findings have significant implications for
diagnosing the root causes of CIV failures in demulsifier injection lines, presenting a procedure to recover
obstructed CIVs, and offering preventive measures against future clogging issues.
Tag: Demulsifier
Relative Viscosity Model for Oil/Water Stable Emulsion Flow within Electrical Submersible Pumps
Electrical Submersible Pumps (ESP) have been used in several scenarios, including water/crude oil emulsion production. The estimation of the emulsion effective viscosity within the ESP is still under discussion due to its complex flow behavior. This work proposes, for the first time, a model to predict the relative viscosity of stable emulsion within an ESP considering the continuous phase properties and ESP operational parameters. The viscosity model was compared to the relative viscosity models for emulsion flow in pipelines and the mean absolute percentage error (MAPE) was 14% and 8% for the stable emulsions without and with demulsifier, respectively. For the same emulsion systems, the relative viscosity model was applied to the unidimensional model to predict the ESP performance with the MAPE of 4% and 2% for the stable emulsions without and with demulsifier, respectively. Furthermore, ESP head degradation operating with stable emulsion with and without demulsifier was investigated experimentally.