Drilling design of U-shaped pilot test wells for geothermal energy in Daqing Oilfield

Geothermal energy is a green, low-carbon, recyclable and renewable energy. The geothermal gradient in the block X of Daqing Oilfield is high, with an average temperature gradient of 4.3 °C/100 m, the formation temperature at a depth of 3 000 m is 120−135 °C, and there is no oil and gas interference in the deep layer, which meets the basic prerequisites for the development and construction of the geothermal energy test area. To realize the clean replacement of geothermal energy in the coal-fired boiler room of Daqing Oilfield, in view of the construction difficulties of poor diagenesis and loose cementation in the upper formation of block X, as well as the water injection development of the lower Putaohua and Fuyang oil layers, high formation pressure and gas bearing in both layers, this paper takes the pilot test wells X1-1 and X1-H1 as examples to optimize the drilling design from the aspects including wellbore structure, BHA, drilling fluid system, and cementing technology. The optimization achievements of the drilling design meets the needs of geothermal well drilling, and the improvement of the technical system for the exploration and development of mid and deep geothermal energy.