1st Development of Advanced Purification of Produced Water Technology at Greater Sirikit Oil Field by Dissolved Gas Flotation Technique

Abstract

The production of S1 Greater Sirikit Oil Field production primarily contributes from waterflooding operation, where water is reinjected into reservoir to increase reservoir pressure and sweep movable oil to adjacent production wells. Estimated oil gain from waterflooding is expected to be 34 MMSTB with upside volume of 19 MMSTB. One of the complexities of waterflood operation is water qualities. As High solid particles and oil content presenting in injected water leads to reservoir plugging indicating by an increase in injection pressure and reduction in injection rate. With 53% of total water injection wells show signs of plugging, water quality improvement is one of the major projects initiated by S1 asset to tackle the problem. Inadequate produced water treatment results in excessive solid particle and oil in water content. Eventually, it will effect on waterflooding and EOR performance. To maintain production, it is required to improve quality of water treatment in order to sustain oil gain. The gas flotation is one of promising technology and practically established methods to enhance separation of oil substances and particulates from water when simple gravity separation is not sufficient to reach the desired concentration. In this project, the most challenged of this project are of necessity of Outlet TSS Concentration below < 20 and 80% removal particle size > 5 microns and Oil Outlet concentration below 25 ppm, whilst the TSS and oil inlet are approximate 200 ppm. The conventional flotation technologies consists with two main systems as detailed below. (1) Induced Gas Flotation Technology (IGF), (2) Dissolved Gas Flotation Technology (DGF). The difference between DGF and IGF is the bubbles size generation. Typically, the IGF unit produces bubble sizes ranges more than 100 microns, whilst the DGF unit creates bubble sizes below 100 micron. Engineering team sought for appropriate technologies by reviewing COMPANY's past projects as well as screening the commercial channels. Apart from that, team amalgamated with Chulalongkorn University to gain academic point of view and perform JAR test to confidentially ensure Licensor's Technologies. Several factors shall be controlled and optimized to accomplish the performance guarantee via consideration of Flotation technique (DGF and IGF), Retention Time, Bubble Size, Coagulant & Flocculants Chemical properties, Chemical Compatibilities, Operating Condition Control (Pressure, pH). In addition, the selected vendor executes engineering design and construction to deliver superior water quailities. Starting DGF unit to conduct performance test run, DGF unit captivately devises positive outcome of water treatment and demonstates high accuracy and reliable with corresponded correlation model when feed condition changes.