As of April 13th, as the largest shallow-injection mature ultra-heavy oil field in China, the Fengcheng Oilfield operation area of Xinjiang Oilfield has successfully achieved efficient succession in the development stage through the combined drive and drainage development technology. The cumulative production of oil in the stage has exceeded 10.78 million tons, and the annual production capacity of the block has stabilized at 2.2 million tons, providing important technical support for the efficient development of similar shallow-layer ultra-heavy oil fields in China.
The Fengcheng Oilfield is located in the northwest margin of the Junggar Basin. The oil reservoir is shallowly buried, the stratum heterogeneity is strong, and the crude oil viscosity is extremely high. The mining conditions are already complex. As the oilfield development enters the middle and late stages, the average pumping cycle of oil wells has exceeded 30 rounds, and the problems of uneven layer utilization, steam migration, decline in oil-gas ratio, and production decline have become increasingly prominent. The traditional steam injection mode is no longer able to support long-term stable production. Technological iteration and upgrading are urgently needed.
To solve the development problems, the operation area of Fengcheng Oilfield focuses on technological innovation. After accurately assessing the reservoir conditions and understanding the potential distribution of remaining oil, the combined drive and drainage development technology suitable for shallow-layer ultra-heavy oil exploitation was successfully applied. This technology forms an upper steam cavity through steam superimposition, combines pressure displacement and the effect of crude oil gravity, and efficiently realizes viscosity reduction for exploitation, allowing the heat energy and displacement power to work together, maximizing the activation of remaining oil between wells.
The research team continuously studies the development laws of the steam cavity, continuously optimizes the injection parameters, and formulates precise development plans in stages: in the early stage, overall steam injection to expand the cavity to enhance the layer connectivity; in the middle stage, adopt multi-point injection combined with asynchronous injection to improve the utilization effect of the horizontal section oil layer; in the later stage, use nitrogen to assist in insulation and pressure retention to consolidate the development results, and ultimately achieve simultaneous improvement in production and oil-gas ratio.
Currently, the combined drive and drainage technology has covered 105 well groups, with the daily output of oil in the block stabilizing at over 6,300 tons, the oil-gas ratio has increased by 0.188, and the development benefits have been significantly improved.
In the future, Fengcheng Oilfield will continue to deepen the efficient development of ultra-heavy oil, precisely control the production of well groups, expand the application scale of asynchronous injection and production, accelerate the improvement of well patterns and processes, and continuously promote the improvement and efficiency enhancement of shallow-layer ultra-heavy oil development, providing solid support for national energy security through core technological innovation.