Online Measurement and Analysis Technology of Oil & Gas Multiphase Flow by Magnetic Resonance

Abstract

AbstractIn the petroleum industry, there is a huge demand for oil & gas multiphase flow metering and fluid property analysis. In addition to common production metering and economic transfer, it also includes downhole metering, drilling and completion fluid testing, oil testing, gas testing, storage and transportation testing, etc. This is an important parameter that needs to be mastered to provide flow guarantee for oil and gas production and transportation. So far, the multi-phase flow measurement methods are usually with low-efficiency, low-accuracy, high-costs and delay-delivery, and hard to reflect the real instantaneous fluid producing properties at wellheads or pipelines. Magnetic resonance (MR) technology is considered to be the most promising multiphase flow measurement technology, but at present it also needs to solve technical problems such as low measurement frequency, static measurement of phase holdup, poor environmental adaptability of the instrument, and high cost.Based on the previous work, this paper addresses the problem of low measurement frequency and inability to flow measurement with traditional low-field MR measurement methods, and proposes a dual-antenna measurement method, which increases the measurement frequency from 0.2Hz to 1Hz, and realizes online measurement of phase contents. A novel integrated probe structure is proposed, which widens the working temperature from -30 to 80 °C, increases the pressure range to 40 MPa, improves the anti-electromagnetic interference ability, and increases the measurement range to 600,000 cubic meters/day for the gas phase, while reducing the cost.The instrument has carried out various tests in 50+ wells in China, and the liquid phase measurement error is less than 5%, and the gas phase measurement error is less than 10%. This progress further helps to apply the NMR technology to oil & gas production industry, to realize green, efficient, online, low cost, full range multi-phase fluid measurements. The on-site fluid properties analysis capability moved the laboratory test to the oil & gas fields, improved efficiency, accuracy and reduce costs.As a flowmeter, the device reduces the amount of measuring equipment needed and manage wells more efficiently, as a ‘fluid analysis laboratory’, can provide the first-hand information on the oil/gas properties.