Large Scale Pipe Flow Experiments for the Evaluation of Non-Chemical Solutions for Calcium Carbonate Scaling Inhibition and Control

Abstract Inorganic scaling is a phenomenon of common occurrence both in nature and in industrial operations. In general, its effect can be highly detrimental for the oil industry, as fouling can take place in different stages of the production, from the well bore and downhole production control valves to upstream primary oil processing and separation equipment. The deposition of precipitated crystals on pipe walls and valves can result in severe production decline. Despite the high costs involved in the design and operation of separate lines for additive injection, chemical inhibition is typically the solution adopted by the oil companies to mitigate scaling. The purpose of the present work is to show results of a large scale laboratory pipe flow experiments to evaluate the performance of non-chemical solutions to mitigate and control calcium carbonate scaling. Magnetic, electromagnetic and ultrasound devices have been tested in a set up that simulates the mixing of two incompatible brine solutions that cause precipitation and deposition of calcium carbonate for a high Reynolds number pipe flow. The performance of the devices is evaluated from pressure drop measurements along the pipe, carbonate deposited mass on the pipe wall and reduction of pipe diameter. Additional results comprise evaluation of particle size distribution of the precipitated crystal, scanning electron microscopy, x-ray diffraction for identification of the crystalline structure and pH and conductivity. Results show that the magnetic field furnishes a beneficial effect, as it delays the time observed for the onset of flow restriction in both pipe and valve. The scaling phenomenon is shown to slow down and the delay for the increase in the measured pressure drop range between two to four times in comparison with the tests conducted without the magnetic field. Ultrasound devices are also shown to provide remarkable impact on the delay of the appearance of the scaling effects. The ultrasound field influences the precipitation phenomena so that particle sizes are kept at very small values, which prevent crystal deposition. The main contribution of the present work is to provide an evaluation method of anti-scaling devices based on large scale experiments, which are fairly representative of real field applications.