Mechanical Degradation Onset of Polyethylene Oxide Used as a Hydrosoluble Model Polymer for Enhanced Oil Recovery

Dupas, A.; Hénaut, I.; Argillier, Jean-François; Aubry, Thierry

doi:10.2516/ogst/2012028

Cited by 35 publications

(24 citation statements)

References 30 publications

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“…In a previous study, the mechanical degradation onset of hydrolyzed polyacrylamide and polyethylene oxide has been studied with the above presented degradation and characterization devices (Dupas et al, 2012 a). The mechanical degradation onset takes place when the velocity at the mechanical degradation onset U d is reached.…”

Section: Resultsmentioning

confidence: 99%

Impact of Polymer Mechanical Degradation on Shear and Extensional Viscosities: Towards Better Injectivity Forecasts in Polymer Flooding Operations

et al. 2013

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Field data from polymer flooding operations sometimes indicate a better-than-expected polymer injectivity below fracturing pressure. Current interpretations for this unexpected phenomenon are based either on geomechanical considerations (for unconsolidated sand formations) or on polymer mechanical degradation, potentially occurring in the injection facilities and the near wellbore area. In this paper, a new approach of polymer injectivity is suggested. It is based on the study of polymer mechanical degradation with respect to both shear and extensional viscosities.In the first part of this work, we have investigated the onset of mechanical degradation by submitting semi-dilute solutions of high molecular weight partially hydrolyzed polyacrylamide (HPAM) to extensional laminar flow created by an API capillary system. We have then measured both shear and extensional viscosity of the native and the degraded HPAM solutions. We consider the onset of mechanical degradation to be reached when shear viscosity loss is equal to 10%. At low degradation rate, shear viscosity is unaffected while extensional viscosity decreases up to 30%, whereas, at higher degradation rates, shear viscosity drops by 10% (onset) while extensional viscosity is reduced up to 60%. This means that degraded HPAM with weakly affected shear viscosity can develop much less resistance to extensional flow.In the second part, we have explored the influence of mechanical degradation on injectivity by determining resistance factors of native and degraded HPAM solutions. Solutions have been injected in reproducible unconsolidated sand packs. At low velocities, resistance factors were similar for both kinds of solutions, as expected from their comparable shear viscosities. However, at high velocities, namely where flow in porous media implies high extensional deformations in the vicinities of the pore throats, apparent rheo-thickening was much less marked for solutions degraded at high extensional rate.These results allow understanding why polymers which do not seem to be mechanically degraded according to their shear viscosity can show a very good injectivity, thanks to the reduction of extensional resistance in porous media. They could also lead to establish guidelines for designing new polymer pre-treatment methods aimed at improving injectivity while retaining the mobility control ability of polymers.

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Section: Resultsmentioning

confidence: 99%

Impact of Polymer Mechanical Degradation on Shear and Extensional Viscosities: Towards Better Injectivity Forecasts in Polymer Flooding Operations

et al. 2013

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“…On the other hand, if the chains have no time to disentangle during the stretching process, the degradation should occur between the junction points corresponding to a random process (Muller et al, 1992). In that case, the final state of the chain is no longer dependent on the molecular weight but rather on the characteristic of the network such as the entanglement density c/c* (Dupas, 2012).…”

Section: Drag Reduction Coil-stretch Transition and Polymer Degradationmentioning

confidence: 99%

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

Jouenne¹,

Anfray²,

Cordelier³

et al. 2014

All Days

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Rules of thumb that are used in the industry for polymer flooding projects, tend to limit the distance over which HPAM 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 longdistance 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 both empirical, large-scale pipeline experiments as well as 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 on larger pipes. For pipes with diameter varying between 14" and 22'' at a velocity higher than 1 m/s, the drag reduction percentage is anticipated to be between 45 and 80%. A more refined model was developed to predict drag reduction with less uncertainty.In conclusion, classical design rules applied for water transport (fluid velocity <3m/s) can be applied to the design of a polymer network. Therefor, for tertiary polymer projects, the existing water injection network should be compatible with the mechanical requirements of polymer transportation.

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“…The critical strain rate (̇) is found to scale with molecular weight according to Equation (12). [109] In the case of QSSF the exponent (k) has a value of 2 as can be inferred from Equation (11). However in FTF, where the chains are not fully extended, the exponent decreases to 1.…”

Section: Mechanical Degradation Of Polymers -18 -mentioning

confidence: 99%

“…[102,107,108] Although this phenomenon is widely reported in the literature as 'shear degradation', it is generally believed that simple laminar shear flow is unable to break polymer chains and that extensional or turbulent flow (which itself contains an extensional element) is required for chain scission to occur. [98,102,109] In general, there are two types of elongational flow which are separated by whether or not the residence time (tr) is greater than the polymer chain relaxation time (λ). Quasi-steady-state elongational flow (QSSF) occurs for tr > λ and as such the polymer chains are able to fully extend.…”

Section: Mechanical Degradation Of Polymers -18 -mentioning

confidence: 99%

“…FTF commonly arises from flow contraction geometries found in nozzles and valves. [109] A fully extended polymer chain in QSSF can be modelled as a series of hydrodynamic beads linked together by springs. Under the extensional flow, each hydrodynamic bead is pulled away from the centre due to frictional interactions with the surrounding fluid.…”

Section: Mechanical Degradation Of Polymers -18 -mentioning

confidence: 99%

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Polymeric Drift Control Adjuvants for Agricultural Spraying

Lewis

Evans

Malic

et al. 2016

Macro Chemistry & Physics

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---------The movement of a pesticide or herbicide to an off-target site during agricultural spraying can cause injury to wildlife, plants and contamination of surface water. This phenomenon is known as spray drift and can be controlled by spraying during favorable environmental conditions, and by using low drift nozzles and drift control adjuvants (DCAs). Polymeric DCAs are the most common type of DCA and function by increasing the droplet size produced during spraying. There are, however, two main drawbacks of polymeric DCAs; they are prone to mechanical degradation during spraying which reduces their performance and they can produce oversized drops which reduces the efficacy of the spray. In this review, existing DCA technology is reviewed including the mechanism through which they function.This then provides a platform for the discussion of novel polymeric architectures which have currently not been applied in DCA formulations.-2 -

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Mechanical Degradation Onset of Polyethylene Oxide Used as a Hydrosoluble Model Polymer for Enhanced Oil Recovery

Cited by 35 publications

References 30 publications

Impact of Polymer Mechanical Degradation on Shear and Extensional Viscosities: Towards Better Injectivity Forecasts in Polymer Flooding Operations

Impact of Polymer Mechanical Degradation on Shear and Extensional Viscosities: Towards Better Injectivity Forecasts in Polymer Flooding Operations

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

Polymeric Drift Control Adjuvants for Agricultural Spraying

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