Analysis of Water Injection and Heat Recovery Potential of Abandoned Oil Wells Transformed into Geothermal Wells in Northern Shaanxi

The Chang 2 bottom water reservoir area in the western part of northern Shaanxi constitutes one of the key oil-producing regions within the Ordos Basin. A principal reservoir here is the Triassic Yanchang Formation’s Chang 2 reservoir, which is characterized by favorable physical properties, dynamic edge and bottom water activity, and a high geothermal gradient. This study employs the STARS module of the CMG reservoir numerical simulation software to model water intake and heat recovery processes in the target region. It analyzes the heat recovery rate and efficiency of three water production methods—direct water extraction, four-injection–one-production, and one-injection–four-production—under varying injection pressures. The results indicate that direct water extraction from the bottom water reservoir is challenging. However, the annual heat recovery per well for the four-injection–one-production and one-injection–four-production methods equates to a standard coal production ranging between 190 and 420 tons, suggesting that there is significant potential for water injection and heat recovery in the Chang 2 reservoir in the western part of northern Shaanxi.