Elastic Effects in Polymer Flow Through Straight Capillaries
Authors: Rivera-Rodriguez Jesus , Marsden Sullivan S. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.
This paper was prepared for the International Symposium on Oilfield Chemistry of the Society of Petroleum Engineers of AIME, to be held in Dallas, Texas, Jan. 16–17, 1975. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made.
Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

Abstract
This work presents a comprehensive experimental study of the viscoelastic effects of partially hydrolyzed polyacrylamides and polyethylene oxide solutions flowing through straight capillaries polyethylene oxide solutions flowing through straight capillaries at several high temperatures ranging from 75 degrees F to 180 degrees F. The effects of polymer molecular weight, polymer concentration, and polymer type on viscoelasticity were studied at these temperatures. Among polyacrylamides, Pusher 500, Pusher 700, and XF 4038 were selected. Polyethylene oxides are represented in this study by the polymer Polyox Coagulant.
A capillary rheometer was designed to characterize the elastic response of polymer solutions. All materials in contact with the polymer solutions were plastic because it was established that the use of ferreous metals, including stainless steel, degraded the polyacrylamides to some extent. A capillary device was used to determine if a fluid exhibits elasticity. The elastic contribution to the total end-correction pressure drop, at a given temperature, was estimated by the difference between the viscous contribution and the total end-correction pressure.
Laboratory test data are presented as plots of total pressure drop vs length to capillary radius ratio to obtain the total end correction for each one of the polymer solutions under study. Plots of elastic end correction vs temperature at constant shear Plots of elastic end correction vs temperature at constant shear rate are included.

Introduction
With the shortage of oil and gas supplies, the improvement of oil recovery efficiency has become one of the most important problems of petroleum engineering. The oil production industry has problems of petroleum engineering. The oil production industry has shown an increasing interest in the use of polymeric materials in secondary recovery operations. Therefore, the need for proper understanding of the flow mechanism of these non-Newtonian materials through both capillaries and porous media has arisen.
When a fluid in laminar flow enters a capillary through an abrupt contraction, the velocity distribution undergoes a change from some initial profile at the inlet to a fully developed velocity profile at some distance downstream. Associated with the velocity profile development in the entrance region there is a high-velocity gradient at the capillary wall resulting in higher pressure losses than in the developed flow region. For purely pressure losses than in the developed flow region. For purely viscous fluids, these losses are due to viscous dissipation and it is possible to establish an upper bound for them.