A software tool that facilitates the development of image reconstruction algorithms, and the design of optimal capacitance sensors for a capacitance-based 12-electrode tomographic flow imaging system are described. The core of this software tool is the finite element (FE) model of the sensor, which is implemented in OCCAM-2 language and run on the Inmos T800 transputers. Using the system model, the in-depth study of the capacitance sensing fields and the generation of flow model data are made possible, which assists, in a systematic approach, the design of an improved image-reconstruction algorithm. This algorithm is implemented on a network of transputers to achieve a real-time performance. It is found that the selection of the geometric parameters of a 12-electrode sensor has significant effects on the sensitivity distributions of the capacitance fields and on the linearity of the capacitance data. As a consequence, the fidelity of the reconstructed images are affected. Optimal sensor designs can, therefore, be provided, by accommodating these effects.

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In the oil industry, it is important to measure gas/oil/water flows produced from oil wells. To determine oil production, it is necessary to measure the water-in-liquid ratio (WLR), liquid fraction and some other parameters, which are related to multiphase flow rates. A research team from the University of Manchester and Schlumberger Gould Research have developed an experimental apparatus for gas/oil/water flow measurement based on a flow-conditioning device and electrical capacitance tomography (ECT) and microwave sensors. This paper presents the ECT part of the developed apparatus, including the re-engineering of an ECT sensor and a model-based image reconstruction algorithm, which is used to derive the WLR and the thickness of the liquid layer in oil-continuous annular flows formed by the flow-conditioning device. The ECT sensor was tested both at Schlumberger and on TUV-NEL's Multiphase Flow Facility. The experimental results are promising.

Tfws papaf was sebcted for preaentatmn by an SPE Prcgram Canmmae following rewew of mfamahon Con! aineal In an abstract s.ulmm tad by the authcf (s) Ccmlcnw of ma papar as pfe8entad, have nof been revmwad by lha Society of Petrolaum Engmaers and ale subject to cm'rMon by the author(s) The ma!enal as pmsemed, does not necessary reflect any pomt$m of the SOmaty of Petrolmm Ewmemrs, is offcars, or mambars Pap-am presanted at SPE meslmgs are subpct to pubhcatum rewew by EdNortal Commt!ees of the Somety of Petroleum EngIn%ers Perm!swon to copy !s restricted to an abstracl of not more than 300 wofds Illustralons may not be cOpted The abstract shoulo conlam conspicuous &5muwk@tnenl of where and by whcm the paper was presented V/me L,braflan, SPE P O BOXS33S3S, Richwdscm TX TSCW-2836. U S A lax 01-21 4-952-W35Abstract A joint initiative between BP and Schlumberger began in mid-1994 to develop techniques for the diagnosis and treatment of unwanted fluid entries in high angle and horizontal wells. The first full scale test of the flow diagnosis technology to occur in a BP asset took place in an extended reach well at the Wytch Farm oilfield in November 1995.In order to measure oil and water flow rates it is necessary to measure both the hold-up and velocity of each phase. A novel toolstring combination was developed which incorporated new sensors especially targeted at the stratitied flow regimes encountered in horizontal wells and featured the capability of measuring flow parameters by several independent methods, enhancing confidence in interpretation.The new sensors could independently measure the velocity of the oil and water phases by measuring the time of flight of iniected Dassive fluid markers as well as bv the well . . established oxygen activation method. Fluid holdup was obtained from a nuclear carbon-oxygen ratio method and an imaging tool. Additionally the imaging tool, based on an array of local electrical probes, could give a real time representation of the distribution of hydrocarbons and water in the borehole. Conventional production logging measurements such as the spinner, pressure and temperature were also made.The primary objectives of the logging were to determine the oil and water flow profile along the cemented and perforated liner and monitor the movement of the reservoir oil-water contact. Entry points for oil and water as well as zonal contributions were confirmed by excellent correlation between the various logging sensors.

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