A multiphase flow

Multiphase flow

In fluid mechanics, multiphase flow is a generalisation of the modelling used in two-phase flow to cases where the two phases are not chemically related or where more than two phases are present In fluid mechanics, multiphase flow is a generalisation of the modelling used in two-phase flow to...

 meter is a device used in the oil and gas industry

Petroleum industry

The petroleum industry includes the global processes of exploration, extraction, refining, transporting , and marketing petroleum products. The largest volume products of the industry are fuel oil and gasoline...

 to measure the individual phase

Phase (matter)

In the physical sciences, a phase is a region of space , throughout which all physical properties of a material are essentially uniform. Examples of physical properties include density, index of refraction, and chemical composition...

 flow rates of petroleum

Petroleum

Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...

, water and gas mixtures produced during oil production processes.

Background

Knowledge of the individual fluid flow rates of a producing oil well

Oil well

An oil well is a general term for any boring through the earth's surface that is designed to find and acquire petroleum oil hydrocarbons. Usually some natural gas is produced along with the oil. A well that is designed to produce mainly or only gas may be termed a gas well.-History:The earliest...

 is required to facilitate reservoir

Petroleum geology

Petroleum geology refers to the specific set of geological disciplines that are applied to the search for hydrocarbons .-Sedimentary basin analysis:...

 management, field development, operational control, flow assurance

Flow assurance

Flow assurance is a relatively new term in oil and gas industry. It refers to ensuring successful and economical flow of hydrocarbon stream from reservoir to the point of sale...

, and production allocation .

Conventional Solutions

Conventional solutions concerning two- and three-phase metering systems require expensive and cumbersome test separators, high maintenance, and field personnel intervention. These conventional solutions do not lend themselves to continuous monitoring or metering. Moreover, with diminishing oil resources, oil companies are now frequently confronted with the need to recover hydrocarbons from marginally economic reservoirs . In order to ensure economic viability of these accumulations, the wells may have to be completed subsea, or crude oil from several wells sent to a common production facility with excess processing capacity. The economic constraints on such developments do not lend themselves to the continued deployment of three-phase separators as the primary measurement devices. Consequently, viable alternatives to three-phase separators are essential. Industry’s response is the multiphase flow meter (MPFM).

Historical Development

The oil and gas industry began to be interested in developing MPFMs in the early 1980s. Prior to the 1980s, single-phase measurements alone were sufficient to meet the industry’s needs. However, depleting oil reserves, along with smaller, deeper wells with higher water contents, saw the advent of increasingly frequent occurrences of multiphase flow where the single-phase meters were unable to cope. After a lengthy gestation period, MPFMs capable of performing the required measurements became commercially available. Since 1994, MPFM installation numbers have steadily increased as technology in the field has advanced, with substantial growth witnessed from 1999 onwards . A recent study estimated that there were approximately 2,700 MPFM applications including field allocation, production optimisation and mobile well testing in 2006 .

A number of factors have instigated the recent rapid uptake of multiphase measurement technology: improved meter performances, decreases in meter costs, more compact meters enabling deployment of mobile systems, increases in oil prices and a wider assortment of operators. As the initial interest in multiphase flow metering came from the offshore industry, most of the multiphase metering activity was concentrated in the North Sea

North Sea

In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...

. However, the present distribution of multiphase flow meters is much more diverse.

Market

Industry experts have forecast that MPFMs will become feasible on an installation per well basis when their capital cost falls to around US$40,000 – US$60,000. The cost of MPFMs today remains in the range of US$100,000 – US$500,000 (varying with onshore/offshore, topside/subsea, the physical dimensions of the meter and the number of units ordered). Installation of these MPFMs can cost up to 25% of the hardware cost and associated operating costs are estimated at between US$20,000 and $40,000 per year .

A number of novel multiphase metering techniques, employing a variety of technologies, have been developed which eliminate the need for three-phase separator deployment. These MPFMs offer substantial economic and operating advantages over their phase separating predecessor. Nevertheless, it is still widely recognised that no single MPFM on the market can meet all multiphase metering requirements .