Degradation (or Lack Thereof) and Drag Reduction of HPAM Solutions During Transport in Turbulent Flow in Pipelines

Abstract

Rules of thumb that are used in the industry for polymer-flooding projects tend to limit the distance over which hydrolyzed polyacrylamide polymers can be transported in pipelines without undergoing significant degradation. However, in sensitive environments, such as offshore facilities where footprint minimization is required, centralization of the polymer-hydration process and long-distance transport may be desirable. More-reliable rules are required to design the pipe network and to estimate mechanical degradation of polymers during transport in turbulent conditions.In this work, we present evidence in the form of empirical largescale pipeline experiments and theoretical development refuting the claim that polymer pipeline transport is limited by mechanical degradation. Our work concludes that mechanical degradation occurs at a critical velocity, which increases as a function of pipe diameter. Provided the critical velocity is not reached in a given pipe, there is no limit to the distance over which polymer solution can be transported.In addition, the drag reduction of viscous polymer solutions was measured as a function of pipe length, pipe diameter, fluid velocity, and polymer concentration. An envelope was defined to fix the minimum and maximum drag reductions expected for a given velocity in larger pipes. For pipes with diameters varying between 14 and 22 in. at a velocity greater than 1 m/s, the drag-reduction percentage is anticipated to be between 55 and 80%. A morerefined model was developed to predict drag reduction with less uncertainty.In conclusion, classical design rules applied for water transport (fluid velocity < 3 m/s) can be applied to the design of a polymer network. Therefore, for tertiary polymer projects, the existing water-injection network should be compatible with the mechanical requirements of polymer transportation. For secondary polymer projects, changing the rules of design by taking into account the high level of drag reduction should bring some economy to the pipe design and installation.

Evaluation of Polymeric Materials for Chemical Enhanced Oil Recovery

“…Finally, it is important to mention that many studies concerning shear degradation for EOR polymers contain industrial data (see, for example, [20,95,96]). This shows the immediate importance and relevance of this research, but the authors may not be able to share all of the formulation or characterization details.…”

“…Other industry-based publications report results obtained on a much larger scale [95,96]. In the work by Jouenne et al [95], the degradation of HPAM during turbulent flow in pipelines was considered.…”

“…Other industry-based publications report results obtained on a much larger scale [95,96]. In the work by Jouenne et al [95], the degradation of HPAM during turbulent flow in pipelines was considered. Viscosity measurements of numerous polymer samples (aqueous solution concentrations ranging from 300 ppm and 2000 ppm) collected at predetermined checkpoints along the pipeline provided a good understanding of viscosity losses throughout the transport process.…”

Supramolecular Polymer-Surfactant System for Heavy Oil Recovery

“…The physics of polymer mechanical degradation is reported in [26]. As indicated by Jouenne et al, "flexible polymer chains have the ability to be extended under elongational flow fields [and the] … stretching of the polymer chains can lead to chain rupture" [27]. For example, xanthan gum, which is a rigid rod-like biopolymer with a double-strand helical structure that aligns in the direction of the flow [26], displays a very high shear resistance because it does not stretch under shearing/elongations forces, which reduces the friction forces on the carbon/carbon backbone.…”

Advanced Polymer-Surfactant Systems via Self-Assembling

“…The presence of dissolved oxygen at high temperatures might induce the formation of free radicals which degrade the polymer molecule by cleavage reducing its molecular weight and viscosifying functionality [2]. Besides, if dissolved oxygen is present in the polymer solutions together with very low concentrations of dissolved iron, it might also cause substantial polymer degradation [4,[26][27][28][29][30]. Therefore, to prevent chemical degradation, the AP and the SAP-AP samples were placed in a glove chamber and bubbled with nitrogen at a pressure ranging from 10 to 20 psi for a period of 30 min.…”