A New Concept for Sand Monitoring: Sand Probe Based on the ER Technique

Abstract

This paper describes a new concept for sand monitoring in multiphase flow regimes and presents results from a thorough test programme, run in a dedicated sand probe test rig at Norsk Hydro's Research Centre at Herøya. The sand probe has been developed as a result of the need for sensors that ean give real quantification of the sand content in oil and gas as well as multiphase flow. This type of probe requires no on-site calibration, and has in principle no lower limit on the smallest detectable sand concentration. This sand monitor is based on measurements of change in resistance in thin, corrosion resistantsensing elements, as these are eroded by the sand. The probe is manufactured with typically four sensing elements which together will cover the whole internal pipe diameter. L%e system has been tested under both bubble and slug flow. All tests clearly demonstrate the probe response's linear dependence on sand concentration, and that the probe can measure the sand content regardless of turbulence level. INTRODUCTION The production of sand and solids in oil and gas can represent a major problem in terms of erosion and damage to production equipment. Sand production can also lead to a degradation or, in the worst ease, a collapse of the reservoir. This sand probe has been developed as a result of the need for sensors that ean measure the sand content accurately both in oil and gas as well as multiphase flow. The CarOcean sand probe is particularly beneficial in situations with low gas/liquid ratios, where accurate quantification of sand with traditional acoustic methods has proven to be difficult. This article presents data from a 9 month test programme run in a new, dedicated test rig at the Norsk Hydro Research Centre at Herøya, Norway. The purpose of the tests was to qualify this new type of sand probe, and to develop a computer model to be used for quantitative analysis of the sand content in the flowing medium. The test programme was divided into three parts An initialtest performed in water, a qualifying test in oil and finally, a test in pure gas phase. The data from the gas tests in annular flow were still under analysisat the time when this article was prepared, and will therefore be published later. Four parameters were focused on during thetest programme:Mixture velocityGrain sizeGas-Liquid RatioProbe positioning A large number of data were analyzed during the course of the test programme, to ensure that thederived formula was as accurate as possible. Due to limited space, this article can only present a small fraction of the data.

Experimental Investigations of Offshore Sand Production Monitoring Based on the Analysis of Vibration in Response to Weak Shocks

“…Implanted monitoring methods involve installing a probe inside the pipeline to sense the impact of sand particles on the sensitive components. This approach is suitable for a single low-velocity fluid carrying sand [8,9]. Kesana et al [10] used electrical resistance (ER) probes to study the effects of particle size and fluid viscosity on annulus flow and slug flow.…”

Vibration Sensor Approaches for the Monitoring of Sand Production in Bohai Bay

“…For example, Ibrahim and Haugsdal [7] applied acoustic sand detector to obtain the information of sand in pipeline. Braaten et al [8,9] used electrical resistance (ER) method to achieve the sand production signals by changing probe resistance, which was caused by particles impact. Hii et al [10] monitored the particle characteristics in multiphase flow by acoustic emission technology.…”