Polyacrylamide and its derivatives for oil recovery

PAPER 
I. Polyacrylamides - Enhanced Oil Recovery 
Zun Chen,
1
Thomas P. Schuman
1 
and Baojun Bai
2
1 
Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 
65401 
2 
Department of Petroleum Engineering, Missouri University of Science and 
Technology, Rolla, MO 65401 
ABSTRACT 
Polyacrylamide is an umbrella term used to describe the homo-polymer of 
acrylamide and the copolymer of acrylamide with other monomer (the molar percentage 
of acrylamide is over 50% generally). Acrylamide monomer has high activity that makes 
it easier to homo-polymerize and copolymerize with other monomers. Owing to superior 
viscosity increasing property and gelling ability, polyacrylamides become the primarily 
selection for polymer flooding and gel treatment agent in enhanced oil recovery. Recent 
developments, performance, applications and limitations of polyacrylamides and its 
derivatives, including copolymers and hydrogels for enhancing oil recovery are reviewed. 
In particular, preparation methodology, polymer architectures, structure-property 
relationships, lab evaluation and field applications of the polymers are emphasized. High-
molecular weight, comb-type, hydrophobically modified associative, 

---

10 
amphoteric/zwitterionic, and cross-linked PAM architectures and their utility are 
described. Structure property relationships are examined. For cross-linked 
polyacrylamide architectures, the mechanisms of polymer gelling and reversible gelling 
are detailed.
KEYWORDS 
polyacrylamide, oil recovery, polymer flooding, gel treatment 
1. Introduction 
Crude oil is an important commodity raw material for the energy and chemical 
industries. In spite of continued investment and advances in exploiting alternative energy 
sources, oil and natural gas will continue to be a significant portion of US and global 
energy portfolios for decades.[1] In the first (primary) stage of oil recovery, the oil is 
displaced by its own reservoir energy, such as gas drive, water drive, or gravity drainage. 
In the second stage, external fluids such as water or gas were injected into the reservoir to 
maintain the necessary pressure and displace the oil towards to the production wells. 
After the secondary oil recovery, there are still two thirds of the original oil left in the 
reservoir[2] and in most cases, 40-50% of the original oil in place (OOIP) is not 
produced[3]. The tertiary oil recovery, also named the enhanced oil recovery (EOR) uses 
unconventional hydrocarbon-recovery methods that target the oil volume remaining in 
reservoirs after conventional-recovery methods.[4] Among the various EOR methods, 

---

11 
thermal methods are primarily used for heavy oils and tar sands; non-thermal methods are 
normally intended for light oils. For the non-thermal methods, chemical methods have 
been uneconomic in the past but hold the promise for the future.[2, 4-6] Injecting 
polymer solution into reservoirs to displace oil, called polymer flooding, can yield a 
significant increase oil recovery.