Independent innovation breaks through technological barriers
As early as 2015, North American oil and gas fields were the first to apply the reconstruction wellbore repeated fracturing technology and achieved good socio-economic benefits. This technology is like renovating old houses, it can once again transform the strata and stimulate the potential of shale gas wells.
Dou Ruijie introduced that the repeated fracturing technology for wellbore reconstruction can be used to reconstruct old shale gas wells with lower production contributions. By inserting smaller sized casing into the original casing, sealing the original modified layer section, accurately tapping the remaining reserves between clusters in the potential section, and improving the single well recovery rate. Compared with traditional full well temporary plugging and repeated fracturing technology, this technology can solve problems such as inaccurate sequence and position of ball plugging, unclear liquid direction rules, and effectively improve reserve utilization rate and gas reservoir recovery rate.
In order to tackle this technology, at the end of 2020, Jianghan Petroleum Engineering Company's downhole testing company collaborated with Jianghan Oilfield and other units to conduct research on increasing storage and production in the Fuling shale gas field. After two years of research and development, the reconstruction of wellbore repeated fracturing technology has finally achieved self-reliance, and has been successfully tested in the Fuling shale gas field. The first test well has obtained a high-yield industrial gas flow of 183800 cubic meters per day.
Although the experiment has been successful, due to the complexity of the process technology, the lack of key tools domestically, high construction costs, and long construction cycles, this technology still needs to be independently innovated to bridge the "last hundred meters" of application.
To this end, Jianghan Petroleum Engineering Company's downhole testing company has established an innovative team for "shale gas reconstruction wellbore repeated fracturing", and has partnered with Jianghan Oilfield to establish a multi professional domestic tool and material research group. Based on benchmarking foreign key technical indicators, the company has carried out technological innovation around the entire technology chain. Based on the geological conditions of the Fuling shale gas field, the characteristics of the horizontal wellbore, and the distribution pattern of remaining reserves, the team has chosen a different direction from the North American reconstruction wellbore repeated fracturing technology in terms of casing size and string loss in the reconstruction wellbore, forming an optimized design technology for repeated fracturing technology with the utilization of inter cluster remaining storage as the core.
Through continuous practice, the above innovative team has systematically carried out research on wellbore reconstruction, repeated fracturing technology, and domestication of well entry tool materials, forming 9 key technologies, breaking through 8 key tool and material research and development difficulties, achieving independent reconstruction of wellbore fracturing technology, domestication of key tools and materials, and obtaining multiple national invention patents.
