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Novel water soluble polymeric drag reducing agents

Project Overview

The focus of this research is to develop water soluble associating polymers with drag reducing properties and polymers that would dissociate with predetermined trigger. Water soluble polymers play a vital role in the gas and oil industry. It has been proven that adding a small amount of water soluble polymer to a solvent leads to a considerable reduction of mechanical drag in the pipe flow. This in turn creates improved gas and oil yields. It is known that the performance of polymers is highly dependent on molecular weight since increasing the molecular weight improves drag reduction. Unfortunately the drag reduction effectiveness can be reduced by mechanical degradation of the polymer solution. Moreover the degradation of the drag reducing agent is proportional to its molecular weight. A compromise between high molecular weight and shear stability is therefore required. Associating polymers have been shown to be of a great importance in drag reduction experiments since association creates high molecular weight macromolecules. Furthermore the shear degradation effect could be reduced for associating systems, since the breakage of secondary bonds would occur preferentially to the cleavage of the polymer backbone.

The use of polymers as drag reducing agents presents however the serious problem of absorption in reservoirs causing a decrease in the flow of natural gas or oil into the well. The absorption of polymer is especially undesirable in shale gas reservoirs where permeability is extremely low. Moreover it has been shown that there is potentially higher risk of polymer adsorption when associating polymers are used comparing to non-associating homologues. The use of associating polymers therefore requires more expensive clean up and for the applications in shale reservoirs availability of polymers able to dissociate under specific trigger would be beneficial. A potential solution in achieving this would be to use stimuli sensitive associating polymers which can be switched between states: associated and dissociated. Whilst in associated state polymer would raise viscosity of fluid and promote drag reduction and after hydraulic fracturing the associations would be switched off allowing the natural gas to flow freely towards the well. This association would then be potentially restored when polymer flows back to the surface hence the polymer could be reued again.

Researcher

Edyta Lam
PhD student

Supervisors:
Prof. Alexander Bismarck
Dr. Joachim Steinke 

Sponsor:
EPSRC & Halliburton

 

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