Polymer Flooding Separate Injection and High Efficiency Measurement and Adjustment Technology

Daqing Oilfield is the largest onshore oil field in China. Polymer flooding plays an important role in the development of Daqing oil field, producing more than 10 million tons of oil for 11 consecutive years. If the injection is not carried out separately, polymer solution will advance along the high permeability layer, which will lead to the serious ineffective and low efficiency cycle, and reduce the production degree of the low and medium permeability layers, which will affect the overall development effect of polymer flooding. Therefore, stratified injection must be carried out, and a new type of delamination injection process string should be developed.1 The whole process integrated separate injection column was designed. The throttle element adopted the streamline annular pressure reducer structure. When the polymer solution passed, the molecular chain expanded and contracted, forming the effective throttling pressure difference and the flow rate 70m3/d. The maximum throttling pressure difference can reach 2.5 MPa, which can effectively control the injection amount into the high permeability layer and improve the production degree of the reservoir. The structural design of streamline ring pressure reducer can effectively control the degradation of polymer solution and reduce the viscosity loss rate from 12.3% to 8%, which ensures the maximum economic benefit of injecting polyacrylamide dry powder. The oil displacement effect of polymer solution is improved effectively. Developed a complete set Electric direct reading and high efficiency measuring and adjusting technology are used in this paper. From the "manual test" to the "cable controlled direct reading" mechatronics, the injection test is developed from the "manual trial" to the "cable controlled direct reading" era. This technique has been applied in 6464 wells in Daqing Oilfield. The success rate of one salvage operation has been raised from 75% to 96.4% and the testing time of the 3-5 interval wells has been reduced from 5.2 days to 2.5 days, and the injection profile has been obviously improved. The effective production thickness ratio is increased from 62.8% to 74.7%, the oil production ratio is increased from 52.1% to 68.7%, and the oil recovery factor is increased by 2 percentage points. It is especially suitable for the old oil field to enter into the high water cut development. Effective technology for further improving oil recovery after stage.