A method for the development of ultra-deep heavy oil reservoirs with dilute gas

Wells in the heavy oil producing blocks of the Tahe Oil Field are usually very deep and demand a large amount of dilute gas, yet have a low yielding rate. Conventional techniques can no longer meet production needs. Nitrogen is now applied to dilute gas injection. Injection depth, nitrogen amount, choke size and the start-up pressure of gas lift were discussed. This new method was practiced in well YQ5-1 in Yuqi area and proved successful. Blending rate decreased from 11:1 to 3.4:1, and single well yield increased from 10 t/d to 38 t/d. It saved dilute gas and raised oil production.