Study on profile control system containing oily sludge produced from polymer flooding

ABSTRACT

In order to reasonably reutilize oily sludge produced from polymer flooding (OSPPF) in the Shengli oilfield, firstly, the basic characteristics of OSPPF are analyzed through SEM, pH meter, and a Particle Size and Zeta potential analyzer. Then, the effects of different factors on the gel profile control system were systematically analyzed. The optimized prescription of the gel profile control system was 0.4% polymer + 0.1% emulsifier + 16% OSPPF + 0.05% stabilizer + 1.2% crosslinker + 0.1% pH regulator, with a gelling time of 32 h and gelling viscosity of 49910 mPa·s at 60°C. Finally, the application performances of the profile control system were evaluated. The results showed that the profile control system had a good anti-shear performance which could continue to form a gel with a viscosity of 45138 mPa·s after 30 min shear. Meanwhile, the gel profile control system exhibited good viscoelasticity and thermal stability so that the viscosity retention was about 90% at 60°C after 180 days. Furthermore, the permeability ranged from 21.24 to 29.63 μm², plugging rates were larger than 94% and it was suitable for profile control in high-permeability zones. Therefore, this technology not only solves the pollution problem of OSPPF but also enables resource reutilization.

KEYWORDS:

• Oily sludge
• emulsion suspension system
• crosslinker
• gel profile control system
• reutilization

Declaration of interest statement

The authors declared that they have no conflicts of interest to this work. We declare that we have no conflicts of interest to disclose in the submitted work.

Additional information

Funding

The authors are grateful to the financial support of Major National Science and Technology Projects[NO.2017ZX07402003, NO.2016ZX05040-005].

Notes on contributors

Yingyue Zhu

Yingyue Zhu, master, received her chemical degree from Tianjin University in 2020, and her research is on resource reutilization of oily sludge.

Xuerui Liang

Xuerui Liang, is pursuing a degree in applied chemistry of Tianjin University, and her research focuses on cleaning oily sludge.

Yuqin Tian

Yuqin Tian, senior engineer, received her PhD from Yangze University. Her research is on tertiary oil recovery and water plugging profile control.

Zhanqiang Wang

Zhanqiang Wang, master, received his chemical engineering degree from Tianjin University in 2020, and his research is on preparation and photocatalytic properties of nanocomposites.

Xia Feng

Xia Feng, received her PhD on biochemistry from Tianjin University in 2003, and now she is an associate professor of Tianjin University. Her research is about biocatalysis, biotransformation and its application in drug research.

Rongjiao Zhu

Rongjiao Zhu, received her PhD on chemistry from Tianjin University in 2009, and now she is an associate professor of Tianjin University. Her research focuses on synthesis and application of oilfield chemicals.