Well completion technologies for the ultra-deep fault-dissolved oil and gas reservoir in Shunbei Oil and Gas Field

Shunbei Oil and Gas Field is an ultra deep fault-controlled oil and gas reservoir and the well completion here suffers several problems. For example, completion tools get failed, hole collapse happens, multi-body productivity mobilization cannot be realized in the horizontal section, and pipe corrosion is serious. As a result, the open hole completion mode originally used in karst fractured-vuggy oil reservoirs is less adaptive and the efficient development of oil reservoir is hindered in Shunbei Oil and Gas Field. In this paper, the essential characteristics and behaviors of ultra deep fault-controlled oil reservoirs were revealed by researching the characteristics of fluid mechanics, rock mechanics and reservoir engineering. And accordingly the productivity maximization scheme was formulated. Then, a series of efficient well completion technologies characterized by productivity maximization for fault-dissolved oil reservoirs were developed by studying the borehole stabilization technology for broken reservoirs, the efficient well completion technology for thief reservoirs, the staged stimulation technology for heterogeneous reservoirs and the corrosion control technology for high temperature and low sulfur environment. Under the guidance of the productivity maximization scheme, single-well stimulation efficiency is 85.4% and average single-well oil increment is 2.89×10⁴ t. Based on the application of the borehole stabilization technology for broken reservoirs, the production pressure difference is controlled within 16 MPa and the cumulative stable production period is 2 100 d. The success rate of the efficient well completion technology for thief reservoirs is 100%. In the staged stimulation, the displacement is 11.6 m³/min, the total fluid volume is 2 408 m³ and the daily oil production is 150 m³, which is 2.3 times that of the neighboring well. The application of the corrosion control technology leads to cost reduction by about 35%. In conclusion, the research results can provide technical support for exploration and development of Shunbei oil and gas field and other similar oil and gas reservoirs.