A New Downhole Second Heating Technology Pilot in Heavy Oil Reservoir

For the reservoir buried depth up to 1600 m, the developed result is not satisfied because of the massive heat loss in the injection tube. So we must increase steam dryness up to 50% from the value less than 40% to get more oil. A new downhole second heating technology is developed and the main device is the downhole heater. It can be produced successfully by pre-installing special electric wire in coiled tube with insulation around and them and then drawing the coiled tube in special machine. We call it “monolithic-draw” technology. Electrical energy is transported to the heating election and the power can be adjusted from 100 to 1000 kw, so steam quality is improved and then more heat will be injected to the reservoir. The test result show that steam dryness can be increased 25% to 40% when steam injection velocity is 5 t/h to 7 t/h, so improved developed result is got because of high quality steam. We conducted experiments in 8 thermal recovery wells from 2022 to 2025, and the increase oil volume is 941 tons in the 5 wells and the other 4 well are still in production. The input-output ratio reaches 1:3.06. And the technology make SAGD production possible for the reservoir buried deeper than 1300 m because downhole steam dryness can reach 70%. This technology is new developed and it benefits to reduce carbon dioxide discharge because the heater can use green electricity made by wind or sun. It will be widely used in deep buried heavy oil reservoir, and it may be an involution steam producer in comparison with conventional steam producer.