Research on influencing factors of injection capacity in cycle steam stimulation process with horizontal well in Bohai oilfield

Abstract

Since the beginning of the 21st century, the proportion of heavy oil production has been increasing. Cycle steam stimulation (CSS in short) is the prevailing technology for the development of heavy oil reservoirs and has made a great contribution to the development of heavy oil. However, the current research on the factors affecting the steam injection capacity of CSS heavy oil reservoirs and the degree of influence of each factor is insufficient. Oil recovery and heat utilization efficiency are poor, especially in the oil fields with poor reservoir conditions and severe heterogeneity. In this paper, the reservoir geological model of the Bohai oilfield was established, and the CSS development was predicted. The problems in the development process of CSS in Bohai oilfield were pointed out. Then, laboratory experiments were carried out to study the steam absorption law of CSS heavy oil reservoirs in consideration of reservoir permeability, steam injection rate, steam injection temperature and crude oil viscosity. The result showed that higher formation permeability and steam injection temperature could improve oil displacement efficiency; higher steam injection rate would reduce oil displacement efficiency. Finally, the influence rules of different injection-production parameters were clarified to shed some lights on the efficient exploitation of heavy oil reservoirs.