Proceedings of COBEM 2011 Copyright c  2011 by ABCM 21st International Congress of Mechanical Engineering October 24-28, 2011, Natal, RN, Brazil ULTRASOUND MEASUREMENT OF THE CONTENT OF SOLID PARTICLES IN LIQUID MEDIA APPLIED TO OIL INDUSTRY Agesinaldo M. Silva Jr, agesinaldo.silva@usp.br Nicolás Pérez, nico@fisica.edu.uy Marco Aurélio Brizzotti, marcobrizzotti@gmail.com Julio C. Adamowski, jcadamow@usp.br Department of Mechatronics and Mechanical Systems Engineering, Polytechnic School of University of Sao Paulo, Av. Prof. Mello Moraes, 2231 , Cidade Universitária - CEP 05508-030 - São Paulo - SP, Brasil João C. Queiroz Netos Andrade, joaoqueiroz@petrobras.com.br Centro de Pesquisas e Desenvolvimento da Petrobras, Av. Pedro Calmon, 550 - Cidade Universitária - CEP 21941-901 - Rio de Janeiro - RJ, Brasil Abstract. In oil industry, sand content in crude oils is commonly used as a parameter to determine the well deterioration level and to assess horizontal wells collapse risk. The sand content measurement is usually performed by a sand content meter device, which is based on a sieves system. This device requires a human operator to collect and analyze the crude oil samples. In order to allow a real time sand content monitoring in crude oil, this work presents a new ultrasonic technique to determine solid particle concentration in liquids. This technique consists in emitting an ultrasonic wave by an ultrasonic transducer and measuring the backscattered ultrasonic signals produced by sand particles. Therefore, the objective of this work is to develop a measurement cell based on the ultrasonic waves scattering to estimate the sand particles concentration in crude oil. The experimental observations were made with a measuring cell built for laboratory batch testing and continuous solid particles flow. Ultrasound transducers with central frequencies ranging from 5 and 10 MHz in pulse-echo mode were used. Laboratory batch tests using sand particles ranging in size from 100 to 500 μm in diameter shown that there is a linear relationship between the volumetric fraction of particle and ultrasonic backscattered energy. The backscattered energy is proportional to the squared voltage measured from the receiving transducer. The echo signal mean energy at a given time window corresponds to the instantaneous flowing sand content through the cell. A micro-controlled feeder device was developed to perform tests on continuous solid particles flow. An analytical balance was used to calibrate the feeder to operate in the range from 2 to 20 mg/s, producing a water mixture ranging from 200 to 2000 ppm. Tests with continuous flow are in agreement with the expected results from the adopted methodology. A backscattered energy computational model based on a transducer impulse response and a plane piston model was developed to understand the experimental results. This model predicts the linear relationship between the backscattered energy and the particle concentration observed experimentally. The results demonstrate the technical feasibility of continuous flow measurements of sand in oil. Keywords: Ultrasound, Sand content in oil , Backscattering 1. INTRODUCTION Solid particle content measurement in liquid media has practical application in a variety of situations, including chem- ical, petrochemical and food processing. There can be several techniques to achieve such a industrial demand. Con- ventional measurement techniques for solid suspension involves physical screening techniques, gravity-driven methods that use the density difference for separation and a simple balance for weighing the solid content. Most recent meth- ods involves nondestructive techniques such as laser diffraction, gamma-ray attenuation, near infrared spectroscopy and ultrasonic waves. Oil production in unconsolidated or poorly consolidated sandstones typically generates sand production. A high sand production may limit the petroleum production, damage the equipments, generate total production cessation, loss of well control, cause fire and environmental damage. Therefore, sand content monitoring within oil production is used as param- eter to determine the well deterioration level, to assess horizontal wells collapse risk and oil-drilling platform productivity. Currently there is an extensive literature of ultrasonic non-destructive techniques for liquid testing (J C Adamowski, 1995), as well as solid particle concentration in liquid media measuring methods (He and Hay, 1993). The studied technique is the ultrasonic backscattering, which is based on the principle of acoustic wave scattering (Kinsler, 1982). Therefore, this paper has the purpose to understand the main mechanisms of acoustic scattering by checking their dependencies in terms of concentration, particle size, media properties involved, seeking their application in the measurement of sand content in crude oil production. This paper is organized in five section. Following this introduction, the next section describes a ultrasonic measurement principle to provide a numerical model to study the involved acoustic phenomena that occur in acoustic waves propagation in liquid media containing solid particles such