Session: 11-10-01: Multiphase Flow Applications

Paper Number: 164271

Determination of Emulsion Layer Watercut in Oil-Water Flow In
Horizontal Pipe Separator 

Produced water (PW) is one of the largest unwanted byproducts of the oil and gas industry. The U.S. petroleum industry produces over 24 billion barrels of produced water annually, nearly 70 times of all hazardous liquid waste. As the reservoir matures, the fraction of water in the total produced fluid increases. Effective cleaning and conditioning of PW is essential for “green operations," minimizing environmental contamination risks and protecting water resources. Conventional vessel-type gravity-based separators have been used in the past by the petroleum industry for oil-water separation. Horizontal Pipe Separator (HPS^©), consisting of either a single pipe configuration or manifolded pipe configuration, is an attractive alternative to the gravity-based separator, owing to its simplicity and applicability for subsea or onshore production.

As the well-mixed oil-water mixture flows along the horizontal pipe, due to gravity, layers of oil and water develop at the top and bottom, respectively. A dense packed zone of droplets of the dispersed phase in the continuous phase (emulsion layer) occurs between the clear layers of oil and water, which becomes smaller along the pipe as the clear phases separate. Experimental data were acquired by Othman et al. [1] using mineral oil and water with specific gravities of 0.857 and 1, respectively, in a 7.62 cm ID 10.3 m long HPS. Different water cuts ranging from 10% to 90% with varying mixture velocities from 0.08 m/s to 0.3 m/s are adopted for the experimental investigations. The acquired data include measurements of the separated oil, water and emulsion layer heights along the HPS. However, no details on the watercut in the emulsion (rag) layer were given, which is important for downstream separation of the emulsion.

In the present study, a novel method is presented for determination of the watercut in the emulsion layer in the HPS, which will help to design HPS and operate the downstream equipment to improve significantly the efficiency of separation of oil and water in the HPS. Similar data are gleaned from the CFD simulation results using ANSYS Fluent 16 presented in Kolla et al. [2] and compared with the above experimental data. The results of this study will enable meeting the standards and regulation of PW reuse or disposal through efficient operation of the HPS.

 

Keywords: Produced Water Management, Horizontal Pipe Separator, Emulsion, Watercut.

 

[1] Othman, H., Dabirian, R., Gavrielatos, I., Mohan, R. and Shoham. O.: “Validation and Improvement of the Horizontal Pipe Separator (HPS^©) Model”, SPE-190047-MS, SPE Western Regional Meeting, Garden Grove, California, USA, 22-26 April 2018.

[2] Kolla, S.S., Mohan, R.S. and Shoham, O., “CFD Simulations of Oil-Water Flow Behavior in Horizontal Pipe Separator”, AJKFLUIDS2019-5579, Proceedings of the ASME-JSME-KSME 2019 Joint Fluids Engineering Conference, San Francisco, July 28- August 1, 2019.

Presenting Author: Muhammad Usman The University of Tulsa

Presenting Author Biography: Muhammad Usman is a Ph.D. student at the University of Tulsa, Oklahoma, working on the U.S. Department of Energy-funded project, Produced Water Cleaning and Conditioning. He holds a Master’s degree in Mechanical Design Engineering and has 1.5 years of industrial manufacturing experience. During his master's, he published an article related to his research. His current research focuses on the design and optimization of multiphase fluid flow systems, with an emphasis on energy-efficient solutions for water treatment and conditioning in the energy industry.

Authors:

Muhammad Usman The University of Tulsa
Srinivas Swaroop Kolla Oklahoma State University
Daniel Awofuwa The University of Tulsa
Ram Mohan The University of Tulsa
Ovadia Shoham The University of Tulsa