AbstractElectrical tomography relies on a new generation of non-intrusive soft-field imaging modality which is used for imaging internal material distribution. The main purpose of this research is to investigate the feasibility of using electrical tomography for multiphase flow measurement within the petroleum industry. Accurate in-line multiphase flow measurement is of paramount relevance for the industry to face the current global oil market challenges due to its potential to decrease operational and development costs.
The use of tomography techniques for multiphase flow measurement in the petroleum industry, which has not been fully explored in the literature, provides opportunities to extract key information that can assist with the fundamental understanding of multiphase flows that are found at various stages between the well and the service station pump. Tomography based measurements can be used to improve, develop, or validate empirical flow transport equations as well as to enhance measurement accuracy.
This work is focused on the design and application of an electromagnetic induction meter and an electrical capacitance tomography system for the investigation of co-current hydrocarbon flow in horizontal pipelines. It has been conjectured that magnetic induction tomography may eventually be an attractive and low-cost alternative to multiphase flow imaging. The work addresses the challenges of multiphase flow measurement and gives an insight into the use of tomography technologies for flow regimes identification, in situ phase fractions, and flow velocity information. This is achieved by numerical modelling and experimental work.
The developed electromagnetic induction-based meter consists of a novel hardware design and data analysis approach which allows the simultaneous extraction of information of conductive and non-conductive fluid species whose electrical properties correspond directly to real field industrial applications.
In this work, interface profiles are extracted from tomography measurements which allows instantaneous flow pattern identification. Analysis of the experimental data reveals a recently studied intermittent flow regime structure, whose interactions between the fluids are detailed. The distribution of the phases was found to depend on the inlet conditions and the ratio of inertial to gravity forces given by the Froude number. This characterisation of the flow structures has a significant effect on the flow transitions with potential extended.
Results of this work broaden the operational limits of both electrical capacitance tomography (ECT) and electromagnetic induction tomography (MIT) by enlarging their operational envelopes. It is concluded that provided the noise in the data acquisition system remains within a certain level, single-pair electrical capacitance measurements can be used for non-intrusive measurement of flow with high water contents within a conduit. Furthermore, MIT has the potential to differentiate between non-conductive species for bulk conductivities below 0.6 Sm-1. However, imaging small permittivity changes in a conductive medium is unfeasible, as the changes in conductivity dominate the induced signal. This problem may be overcome by using a multimodal approach combining ECT and MIT for low and high-water contents, respectively.
|Date of Award||Aug 2020|
|Supervisor||Hafiz Ahmed (Supervisor), Olivier Haas (Supervisor) & Andrew Hunt (Supervisor)|