Abstract
To protect the marine ecological environment of Bohai Bay, the waste drilling fluid in Bohai oilfield have to be treated. In the light of the composition characteristics of Biodrill-A drilling fluid, the compounding method of the inorganic–organic flocculants was adopted to assist the flocculation and solid–fluid separation of Biodrill-A drilling fluid. Through the orthogonal test design, the main factors impacting the flocculation effect on Biodrill-A drilling fluid were found to the concentration of inorganic flocculant CaCl2 and the flocculation pH value. The optimal flocculation treatment was further obtained through single-factor optimization. Specifically, when the inorganic flocculant CaCl2 concentration was 0.9 w/v%, the organic flocculant concentration was 0.01 w/v%, the flocculation pH was 8, and the flocculation time was 7 min. Eventually, the final dewatering rate could reach 84.02%. In the optimized compound flocculants, the inorganic flocculant CaCl2 reduced the zeta potential of clay particles by electric neutralization to decrease the repulsion among particles, and the organic one could absorb and wrap the clay particles through bridging curling and electric neutralization after flocculation destabilization. Both inorganic and organic flocculants facilitated the large flocs and particles of clay particles. The field test showed that the inorganic–organic flocculants were suitable for the on-line flocculation treatment process based on centrifugal machine. The waste drilling fluid was reduced by 82%, and the water content of the separated solid phase was as low as 25.7%.
Highlights
As one of the major offshore oil and gas accumulation areas in China, Bohai Bay is a first-class sea area with slow water exchange rate and a long ecological recovery cycle once water was polluted (Peng, 2008; Zhou et al, 2012)
The waste drilling fluid was reduced by 82%, and the water content of the separated solid phase was as low as 25.7%
The results showed that the main factors influencing the flocculation dewatering rate of Biodrill-A drilling fluid were pH value and inorganic flocculant dosage, and the flocculation process should be further optimized through single factor optimization experiment
Summary
As one of the major offshore oil and gas accumulation areas in China, Bohai Bay is a first-class sea area with slow water exchange rate and a long ecological recovery cycle once water was polluted (Peng, 2008; Zhou et al, 2012). From the perspective of protecting the ecological environment of Bohai Bay, it is imperative to achieve zero discharge of drilling fluid and drilling cuttings involved in all offshore oil and gas drilling (GB4914, 2008). Construction and Application of Flocculation System waste drilling fluid treatment. The drilling fluid system is extremely stable due to high polymer contents, which is not conducive to the solid–liquid separation treatment. For this reason, aiming at the Bohai oilfield waste Biodrill-A drilling fluid, this article formulated the inorganic and organic flocculant compound by orthogonal experiment method and optimized the flocculation conditions. This work could provide a theoretical support for the design of Biodrill-A drilling fluid field treatment technology and equipment, and provide an idea for harmless treatment of offshore drilling waste
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
