MULTIPHASE MIXTURE
Reliable Multiphase Pumping Under Extreme Conditions
How progressing cavity pumps ensure continuous crude oil transport
How can an unfiltered mixture of crude oil, water, gas and sand be reliably transported over many kilometres at ambient temperatures of up to 50 °C and with highly fluctuating media composition? This was precisely the challenge facing the operators of one of Africa’s largest oil fields in Sudan's Melut Basin. A robust, reliable, and low-maintenance pump solution was required to ensure the plant’s economic operation.
As a global specialist in manufacturing positive displacement pumps, NETZSCH Pumps & Systems offers innovative solutions for demanding applications in the oil and gas industry. We will show you how progressing cavity pumps ensure stable delivery even under extreme environmental and process conditions.
Individual Consulting
Challenges in multiphase pumping
The medium extracted in the Melut Basin is a multiphase mixture. In addition to highly variable proportions of oil, water, and gas, it contains abrasive sand particles, which increase wear. At the same time, the gas-oil ratio and the proportion of solids vary significantly depending on the source and the extraction phase. The local climatic conditions also play a role. High ambient temperatures of up to 50 °C, surface temperatures of up to 70 °C, sandstorms, and seasonal rainfall place additional demands on the mechanical components, sealing systems, and installations of the pump units. The long transport distances of up to 15 kilometres between the borehole and the central separation plant also require constant, low-pulsation transport to avoid pressure losses and transport interruptions.
Limitations of conventional pump technologies
The operators planned to transport the multiphase crude oil from several sources to central treatment facilities (CTF) and subsequently convey it through a pipeline approximately 1,300 kilometres long. The first section of the transport route, from the well to the CTF, proved particularly critical. Conventional pump technologies were sensitive to the high gas content and varying sand concentrations. This led to unstable flow rates, increased wear on hydraulic components and unplanned downtime. However, the resulting high maintenance costs were difficult to manage due to the remote location.
Robust pumps for reliable multiphase pumping
For this reason, the operators of the oil field in Sudan’s Melut Basin turned to NETZSCH. The global specialist in handling complex media recommended NEMO® Multiphase progressing cavity pumps, specifically designed for transporting media with high gas and solids content. The solution is based on progressing cavity technology, in which a helical Rotorrotor,Rotors,rotorsrotor rotates within a stator. This creates closed pumping chambers continuously transporting the medium from the suction to the pressure side. The pumping mechanism enables a uniform, low-pulsation volume flow without significant shear forces. This prevents undesired emulsion formation while maintaining a stable delivery rate, even at gas-oil ratios up to 50 SCFD per barrel. The generously dimensioned delivery geometries also ensure high tolerance to abrasive solids. Even with media containing high levels of sand, there is no interruption or immediate damage to the delivery elements. This significantly reduces wear, enabling reliable continuous operation. The Z-type swivel joints used also make a significant contribution to high operational reliability. These are characterised by high mechanical strength and are designed for long service life under changing load conditions. Especially in remote locations with limited maintenance access, this robust design has proven its worth. The pump concept was complemented by an installation designed for the extreme environmental conditions. The units were mounted higher on the frame to protect them from standing water during heavy rainfall. Simple sun roofs reduce direct heat gain and help minimise thermal load on components. Overall, this combination of technical design and structural protective measures significantly increases operational reliability.
Today, 20 multiphase pumps are in use across several production blocks, with each block handling the output from up to 24 oil wells. Individual pumps achieve production rates of up to 250 cubic metres per hour. The units have been in continuous operation for more than six years. During this time, there have been no unplanned shutdowns due to production interruptions. Maintenance work on joints, the drive train or bearing housings has not been necessary to this point. Only pumps exposed to extremely high sand loads for extended periods required replacement of stators and mechanical seals. Despite the changing crude oil composition and extreme climatic conditions, the overall process control remains stable.
For operators, this results in significantly higher plant availability and more predictable maintenance, even under the most challenging conditions. If you want to transport complex media safely and economically over long distances, the experts at NETZSCH will be happy to assist you with the application-specific design of your pump solution.
NEMO® multiphase progressing cavity pump
- Medium: Multiphase mixture (crude oil-water-gas-sand)
- Capacity: Up to 250 m³/h
- Temperature: Environment up to 50 °C
- Other: Fluctuating viscosity, high gas content, abrasive sand particles
