Publications

Total E&P Indonesie (TEPI) gas wells are facing shallow zone perforation and therefore sand is expected to be produced at any time during production at surface facilities. Acoustic Sand Detection (ASD) has been used as live sand content monitoring in flowlines and remains the sole sand monitoring system at TEPI to control sand production at surface. It has been used commonly on gas producer wells due to its reliability, mobility, simplicity and light weight compared to sand filter/hydro cyclone unit. ASD system accuracy is affected by flow regime, pipe geometry, velocity, particle size and shape and also noise from production flow. One of the most matters is noise from production flow, specifically cavitations noise, which will impact to unnecessary well ramp-down/shut-in if the ASD system is disturbed and gives incorrect interpretation. Cavitations noise is a noise produced by dynamic process of the flow formation and implosion of cavities in fluids. The impact result of this process is a production loss. This paper explains how to reduce this noise effect on the ASD tool by reducing differential pressure between the upstream and downstream pressure of the wellhead choke and prevent the occurring of cavitations effect. A program was designed for certain wells that are considered to have a cavitations noise issue by considering vapour pressure, critical pressure, wellhead pressure, valve liquid pressure, recovery factor and liquid critical pressure ratio factor. A trial on three wells has been done and good results were achieved - cavitations noise impact to ASD decreased by reducing dP across the choke. This phenomenon is a contradiction with current practises where the well has to be choked down due to high signal ASD which is interpreted as “fake high sand rate”. With this test, the production gain is observed by 3 MMscfd from three wells.