井下油水分离器数值模拟

Numerical Study of Water Con trol with Down hole Oil-Water Separation Technology Khor Yin Yin 1,a , Hussain H. Al-Kayiem 2, William Pao 2

1,2,3 Universiti Teknologi PETRONAS, Mechanical Engineering Department, block 17, Bandar Seri Iskandar, 31750 Tronoh, Malaysia

Abstract. The maturing oil fields with increasing water production can pose a

challenging produced water handling and disposal issues. This paper presents a numerical

study of a motorless hydrocyclone to enhance understanding of the downhole oil-water

separation. The turbulence of fluid flow is obtained using K-ߝ Realizable Turbulence

model for complex swirl dominated flow, while the interface between hydrocarbon and

water is described using the Discrete Phase model. I n this approach, factors which

contribute to the hydrocyclone separation instability were discussed. Discussion is then

extended to the relationship of residence time with pressure difference between overflow

and underflow. These pressure differences are able to relate to pressure condition for high

water cut well which require downhole separation.

1 Introduction

An increasing water production in oil and gas wells due to water influx has encouraged the industry to investigate solution to minimize the impact of concurrent production of unwanted water in the wells. I n the recent decade, there is growing recognition for the need of a controlled water production to meet the immense challenges of increasing water handling cost and to extend the life of the well especially at offshore operation. Virtually, water production in mature field is unavoidable; oil is commonly accompanied by an underlying aquifer, as production rate is increased, oil water contact (OWC) also increases until water breakthrough into the wellbore. The unavoidable premature water breakthrough or water coning could happen due to high pressure drawdown around the wellbore and high mobility of water than oil, where water viscosity much lesser than the oil, water relative permeability much greater than oil. The consequences of increased water production translates to high operating expenses and produced water disposal costs, increased in environmental risk associated with large volumes of produced water, additional requirement for produced water lifting and significantly reduced surface processing facilities ullage for oil. Water production can also limit the well production life via fines migrations and high water production inhibits oil production to production tubing, hence causing low recovery at oil layer.

These lead to a solution to the problem of unwanted water production; the development of Downhole Oil-Water Separation (DOWS) technology. DOWS is a hydrocyclone-based system for downhole separation of produced oil and water and subsequent disposal of the produced water by reinjection within the same wellbore using electric submersible pump. It has been successfully applied in a number of onshore wells, for example Alberta Canada, France, North Sea and China [1]. However, based on lessons learned from onshore and offshore installations, the used of DOWS in a

Corresponding author : khoryin_yin@.my DOI:10.1051/C Owned by the authors,published by EDP Sciences,2014

,/0202 (2014)201conf Web of Conferences 402021313MATEC matec 9

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his is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits