How CFD of Multiphase Flows is Helping Oil and Gas Industry

Computational Fluid Dynamics (CFD) is a design and engineering tool used to simulate the flow of fluids such as air, water, or any fluid in the system and understand the effect of the fluid flow on the surroundings. CFD is best used in case studies, where the system behavior cannot be calculated using conventional calculation methods and needs complex mathematical modeling to capture the behavior. By using this technique, designers can verify that their products will comply with a customer’s specifications early in the design cycle, accelerating the product development process. CFD can be used to calculate pressure drops, heat transfer rates, design mass-flow rates, and fluid dynamic forces such as lift and drag. Hence, CFD is becoming an increasingly important design tool in engineering and also a substantial research tool in certain physical sciences. Due to the advances in numerical solution methods and computer technology, geometrically complex cases, like those which are often encountered in turbomachinery, can be treated.

One of the new areas where CFD is growing as a very valuable tool is in analyzing multiphase flows, especially in Oil and Gas Industry. The presence of solid particles often occurs in most industrial processes involving fluid flows. Typically, in the oil and gas industry, the sand particle is frequently produced and entrained along with crude oil and natural gas through pipelines transportation before reaching any process equipment. During the multiphase flow (presence of more than one phase), particles obtain momentum from the carrier fluid and flow along to impinge on the inner wall of the pipes, fittings, valves, and other pumping devices by causing wear to these facilities. Various flow engineering services perform multiphase flow analysis of flow within pipelines and various equipment to analyze the effect of the different states of fluid on the life of the equipment. Based on the analysis various effects such as solid erosion damages are estimated and CFD consulting is provided in order to minimize the damage due to the erosion in this equipment. Various CFD engineering services perform multiphase CFD flow analysis to optimize the equipment design and minimize failure which may lead to potential oil spillage, operating problems, production loss, resulting in great financial losses as well as safety and environmental concerns. Multiphase CFD analysis is also used for drill tool design to determine the effect of the multiphase flow on the cutting concentration, pressure drop profiles, and various others. Various drilling tools engineering services provide CFD consulting services in order to minimize the pressure losses along with the annular geometry and provide an economic design of the drilling tools.

Solid particle erosion is a complex mechanical process in which the severity of the damage may depend on a wide range of parameters, such as the operating conditions, fluid properties, solid particle properties, multiphase flow regime, wall target material, and its geometry. Various flow simulation services use CFD multiphase flow techniques such as erosion models are used to determine the effects of the solid particles on pipe bends or elbows to determine the erosion of the design and consequent pressure loss or even in worst cases failures due to erosion of the design equipment. CFD consulting is then provided to the clients in order to take appropriate measures such as designing appropriate filters or timely changing the equipment to minimize any losses or sudden failures in the equipment, thus potentially benefitting the client.

Various CFD engineering services use multiphase CFD analysis to design flow separator devices that segregate the solid and the fluid particles. The multiphase CFD analysis will be used to determine the part of the solid particles which cause erosion of equipment in the pipelines and various locations. Based on the results obtained, the CFD engineering services accordingly design flow separators that stop the transport of the solid particles, thus minimizing the damage due to the same. Another area where CFD engineering services use multiphase CFD flow analysis is the design of offshore structures which are continuously subjected to oceanic water which consists of different salts and minerals along with water. These salts and minerals are bombarded on the offshore structures which undergo corrosion and lead to corrosion failure due to the same. CFD engineering services use the multiphase CFD flow analysis to design various protective equipment for offshore structures so as to minimize the impact of the salts on the structures and minimize the effect of corrosion on the same.

Flow simulation services is of great importance in understanding the physics related to downhole fluid flow, maintaining the safety of the downhole tools, as well as promoting oil and gas production. In recent decades, the drilling of horizontal wells has become a proven technology for oil and gas recovery. It is particularly useful in production from thin and naturally fractured reservoirs, reservoirs with gas and water conning issues, offshore environments, and various enhanced oil recovery projects. Various flow simulation services use multiphase CFD analysis in predicting the two-phase gas-liquid and liquid-liquid flow behavior to provide continuous and safe transportation of production fluid from the downhole to the processing facilities. These flow simulation services provide very useful data to the clients such as flow patterns, liquid holdup, and pressure drop in the complex flow conditions, thus optimizing the design of drilling tools to minimize the same. Finally, flow engineering services use multiphase CFD flow analysis for various purposes such as optimization of drilling hydraulics and hole cleaning, wellbore stability analysis, cutting transport in the wellbore, and optimization of flow through the oil and gas wells.

Multiphase CFD analysis are turning out to be a boon especially in Oil and Gas industry where there is a need to maximize production and minimize any delays or losses as well. These analyses not only help in prolonging the life of the equipment required in oil and gas but also make sure that there are no lethal environmental disasters due to the same. As advancements in CFD keep on increasing, it will soon be possible to visualize exactly what is happening inside a pipeline using CFD analysis without the need to physically see the same. And all will be done at a fraction of the cost of doing experimental testing.