Research on the Development Technical Policy for Complex Condensate Gas Reservoir

Abstract The geological states of QS condensate gas field are complex, featuring nearly north-south trending faults in its central section. The gas layer’s thickness is only 15 m, and the physical properties are very poor, with a permeability of just 1.78 mD. Additionally, the pressure difference between the reservoir and the dew point is small, which is only 2.89 MPa. The lower sections of the reservoir are characterized by small oil rings and edge-bottom water. These complex geological and fluid characteristics increase the difficulty of developing the gas reservoir. This paper takes numerical reservoir simulation technology, combined with gas reservoir engineering methods and analogy methods, to demonstrate the development technical policy for QS gas field, which is that the reservoir adopts a well spacing of approximately 800 m and deploys horizontal wells for depletion development, with horizontal sections length ranging from 800 m to 1200 m. The gas withdrawal rate is set at 3.5% to 4%, while the oil avoidance height is maintained above 15 m to 20 m. Because of the small size of the oil ring, it focuses on natural gas production while the development of the oil ring is not considered. Under the guidance of this technical policy, the pilot production capacity of QS condensate gas field has a high compliance ratio, with stable pressure and production during pilot testing, the retrograde condensation effect is weak, and the pilot production results are excellent. QS condensate gas field has become the first condensate gas field in the Junggar Basin to be efficiently developed using horizontal wells overall.