Research and Test on Electric Heating Production Technology for Bottom Water Heavy Oil Reservoir in Dagang Oilfield

The ordinary heavy oil reservoirs of Class II and III in Dagang Oilfield exhibit the "double low" development characteristics of low calibrated recovery rate (4.8%–17.3%) and low recovery degree (2.8%–11.3%) due to the high oil-water mobility ratio, and urgently need to switch to development methods to improve recovery rate. Based on the characteristics of the reservoir and the current situation of oil wells, research and tests on electric heating technology for increasing production in bottom water heavy oil reservoirs have been carried out. Through the thermal reaction test of crude oil, it was confirmed that the thermal cracking and condensation reactions of crude oil intensify at 350–400 ℃, hydrogen sulfide is produced at 350 ℃, and coke begins to form between 400–450 ℃. Innovatively designed an integrated string assembly process for 5–1/2 inch casing horizontal wells featuring heating, artificial lift functions, and temperature monitoring, which successfully trialed in a single test run. After two rounds of heating, the daily oil production of the test well increased from 1.09 tons to an average of 1.97 tons, with a cumulative increase of 119 tons, preliminarily verifying the technical effectiveness and process feasibility. At the same time, it provides technical reference for electric heating to increase production in similar oil reservoirs.