Understanding the Impact of Polyacrylamide Present in Oil/Water Emulsions on Thermally Formed Deposits on Steel Surfaces

点击翻译按钮获取中文摘要

Flooding an oil reservoir using pressurized water containing gelation agents is a common method of enhancing the extraction of underground hydrocarbons. Canadian Natural Resources Ltd. (CNRL) has increasingly relied on this method to improve heavy oil yields. Over the lifetime of the production well, the gelation agent will eventually emerge in increasing concentrations as part of the produced oil/water emulsion. During de-emulsification of the well fluids at a processing facility, oil is separated from the water and the gelation agent. In recent years, there has been a decrease in the service life of the direct-fired tube within the treaters at upstream oil facilities, associated with the deposition of a carbonaceous layer on the tube surfaces and subsequent local heating and deformation of the tube material. Growth of the deposit appears to be correlated with an increase in amount of gelation agent found in the produced oil/water emulsion. This issue has resulted in considerable down time and significant repair costs at the treaters. In direct collaboration with CNRL, the Birss group at the University of Calgary will perform a detailed and systematic analysis of the nature and composition of the surface deposits and how they are formed under simulated field conditions, and then use this information to propose practical, cost effective mitigation strategies. Bench top studies will focus on how the concentration of added gelation agent and other chemical components in the oil/water emulsion impact the type and rate of deposit growth during high temperature treatment. Subsequent work will explore the use of additives to slow this growth. Ultimately, an understanding of the mechanism of deposit formation will be developed and mitigation strategies will be proposed. With oil production margins becoming ever tighter in a low oil price environment, it is critical to bring down production costs and eliminate wasteful downtime caused by frequent firetube failures. The knowledge produced by this work will be used to improve the service life of the oil processing treaters at upstream facilities, thus removing a large barrier to the expanded use of this enhanced oil recovery technique within Canada.