Research On Measuring Methods With Electromagnetic Correlation For The Flow Of Oil-gas-water Multiphase Flow

In China’s oil production, as the onshore oil enters the exploitation stage of highwater cut the development of oil exploration technology raised higher requirements for oilmeasurement. The sector of oil field technology has been looking for measurement devicewhich can measure the flow of oil-gas-water multiphase flow(oil-gas-water three phaseflow as the main body, containing small amount of solid phase material) online, can ensurethat the flow measurement has high accuracy and wide range, has simple measurementprocess, can measure continuously, has strong anti-jamming capability, has small size, haslight weight, can reflect the production dynamic flow of oil in real time. Chineseproduction logging technology of oil-gas-water multiphase flow is ahead of othercountries. However, there are no measurement devices for multiphase flow which havebeen used in production logging and flow and obtained good results.This study provides a new solution and approach for flow measurement ofoil-gas-water multiphase flow. An innovative electromagnetic method model is presentedwhich can be applied to oil-gas-water multiphase flow measurement of production loggingaspects. We conduct research on the theory of flow measurement model and the keytechnology of sensor model when its applied to production logging. This study focuses onoil-gas-water multiphase flow measurement in the narrow space environment of oilproduction logging. This work is theoretical basis for the development of new downholeoil-gas-water multiphase flow measurement instrumentation. There is theoretical referencefor electromagnetic correlation flow meter implementation, which has good valu for flowmeasurements of other environmental oil-gas-water multiphase flow.Firstly, we introduce the applications background of oil-gas-water multiphase flowmeasurement in oil production logging. In order to solve the inadequacies of theoil-gas-water multiphase flow measurement in current production logging aspects, Aninnovative flow of oil-gas-water multiphase flow measurement methods have beenproposed——the model of electromagnetic correlation flow measurement, which willachieve oil-gas-water multiphase flow measurement of oil production logging.Secondly, two pairs of detected electrodes of electromagnetic correlation flow measurement sensors separated by an appropriate distance, so, designing longer axialexcitation coil in the sensor is required. In this paper the theoretical analysis of themagnetic field generated by the longer axial excitation coil in measurement space of thesensor.Thirdly, the sensitive field sensitivity is defined to analyze the disturbancecharacteristics of the flow sensor, and build a simulation model to analyze the distributionof sensitivity field in flow measurement sensor and the disturbance characteristics of flowsensor with non-conductive objects exit in the fluid.Then, the response relationship between measuring signals of sensor detectionelectrodes and which distribution or holdup non-conductive(oil or gas) in the fluid isstudied. On the other hand, the internal magnetic field of electromagnetic flow sensor withdifferent magnetic permeability material in the fluid is analyzed theoretically, on this basis,we study the response relationship between flow which containing different magneticpermeability materials in the fluid and the measurement signals of sensor detectionelectrodes. The results of study demonstrate the feasibility of measurement oil-gas-watermultiphase flow by the way of electromagnetic correlation.Finally, for the special circumstances of the production logging requirements, westudy the key design parameters method of downhole electromagnetic correlation flowmeasurement sensor which applied to oil production logging. the design principles ofMagnetic correlation flow measurement sensor excitation structure in the narrow space isstudied; the separated distance of two pairs detection electrodes is studied; the relationshipbetween detection electrode size and the size of non-conductive material in measurementfluid is studied; all of these will provide a reference for parameter design of the downholeelectromagnetic correlation flow measurement sensors.