The oil and gas industry is one of the industries that demands highly engineered and varied processes. In this article, we will discuss some of the most common processes encountered in the oil and gas production process.
The wellhead is above the actual oil or gas well leading to the reservoir. The wellhead can also be an injection well, used to inject water or gas back into reservoir to maintain pressure and level to maximize production. This process consists of reinforcing the wellbore with a casing, evaluating the formation pressure and temperature, and then installing the appropriate equipment to ensure an efficient flow of natural gas out of the well. Well flow is controlled by a choking device.
Onshore – The well flow is brought to the main production facility via a pipeline collection network and manifold system. The aim is to regulate production so that production levels increase, utilize the reservoir as well as possible, adjust the composition of the well flow (gas, oil, etc.) appropriately.
Offshore – Dry completion of the well in the central main field feeds directly to the production manifold, while the outer wellhead tower and subsea installation feed via multiphase pipelines back to the production rungs. A riser is a system that allows the piping to “go up” to the superstructure. To float a structure, this involves taking the weight of the structure and moving it. For heavy crude oil, diluents and heating may be required to reduce viscosity and facilitate flow rates.
Some wells have pure gas production which can be taken directly to gas treatment and/or compression. More often, wells consist of a combination of gas, oil and water and various contaminants must be separated and processed. The production of separators comes in various shapes and designs.
The gas from the pure gas well has sufficient pressure to be supplied directly to the pipeline transport system. The gas from the separator generally loses so much pressure that it must be compressed to be transported. The turbine compressor benefits their energy by using a fraction of the compressed natural gas. The turbine functions to operate a centrifugal compressor, which contains a type of fan that compresses and pumps natural gas through pipes.
Metering, Storage and Export
Metering on oil and gas are at the measurement site which aims to measure several variables of oil and gas fluid flow in the pipeline. The quantities observed in the pipe are pressure, temperature, fluid level, flow rate.
Most industries do not allow local storage of gas, but oil is often stored before loading on ships, such as shuttle tankers that carry oil to larger tanker terminals, or directly to crude carriers. Offshore production facilities without pipelines rely on storage of crude oil in the ship’s bottom or hull, to allow a shuttle tanker to offload goods about once a week. More complex productions generally have tank warehouses that store more crude oil to deal with changes in demand, transportation delays, etc.
The processes above are closely related to fluid mechanics. One of the most common methods for designing a system of production processes in the oil and gas industry is to use Computational Fluid Dynamics (CFD), which is a method of solving fluid mechanics equations and even chemical reactions using a computer, so that comprehensive and detailed results are obtained. >> Click here to learn more about CFD!
Contributor: Daris Arsyada
Devold, Havard. 2006. Oil and Gas Production Handbook: An Introduction to Oil and Gas Production. Oslo: ABB ATPA Oil and Gas.