METHOD FOR DETECTING SOLID PARTICLE ENTRAINMENT ZONES IN A WELL

This invention relates to the petroleum industry. More particularly, this invention pertains to the method of detecting zones of solids (sand or proppant) production in a well where the solids are carried up by fluid and gas flows. To implement the method, at least one well operating regime is established, which is characterised by the presence of fluid flow carrying solid particles either along the wellbore or in one or more formations. At least one instrument for objective measurements of acoustic signal amplitude is run in or pulled out of the well either at a constant speed or stopping at stations. Acoustic signal amplitude is measured either at a station or during running in or pulling out of the well using at least one instrument for objective measurements of acoustic signal amplitude. The acoustic signal amplitude measurement data obtained in the well are processed, detecting amplitude peaks in the registered acoustic signal. At each depth, the peak shapes resulting from the measurements are compared with the reference ones and only those peaks that correspond to impacts of solid particles are discriminated. The solid particles are counted and the zone of solids production in the wellbore is identified. During downhole logging on a down pass or on an up pass, the number of solid particles is estimated at one-second intervals. During downhole logging at stations the number of solid particles is estimated for each station. The duration of a measurement at a station is 10 seconds or longer. The distance between stations is equal to the length of the instrument for objective measurement of acoustic signal amplitude. Acoustic signal amplitude is measured simultaneously with three acoustic signal amplitude measuring instruments with the distance between stations being three times longer than the length of the instrument for objective measurement of acoustic signal amplitude. The instrument for objective measurement of acoustic signal amplitude is run in or pulled out at a constant speed of maximum six meters per second for the instrument one metre long, using additional rubber centralisers. For monitoring of solid particles and selection of an optimal operating regime, an additional solid particle surface detector is installed. Utilisation of this invention will enhance the accuracy of solid particles detection in a well. 7 subclaims, 13 figs.