An Improved Further Treatment Process and Parameter Optimization for Waste Water in Polymer Flooding Oilfield

This paper presents an improved further treatment technical process for polymer-containing waste water in the oilfield. The core equipment of the system is a forced filtration unit, which uses walnut shells as the main filtering material, avoiding such disadvantages of ordinary mechanical filtering materials as being easy to be contaminated and difficult to be cleaned. It is equipped with an automatic backwash unit, which may timely and thoroughly back wash and prevent the filtering material from hardening and the quality of effluent water from deteriorating, etc. Compared to application of scrubbing pump at outside of the body, it may save a large amount of cost. After optimizing the backwash parameters by using the orthogonal experimental method, the backwash cycle is extended by 15%, the backwash intensity is decreased by 28.6%, the backwash time is saved by 40%, water is saved by 46.8%, and the electricity is saved by 23.44%. Experiments and field tests indicate that the after-filtration water quality is assured. It can improve the work efficiency, extend the service life of the filtering material, reduce the overflow risks as a result of a large amount of backwash water, effectively save resources, and deliver good economic and social benefits.