Lost Circulation Mechanical Model and It’s Application in Permian Igneous Rocks in Shunbei Oilfield

Abstract

The Shunbei Oilfield is a major discovery of Sinopec in the ultra-deep marine carbonate rock field, and it will become the main battlefield for Sinopec to increase reserves and production. At present, the exploration and development of the Shunbei Oilfield is mainly concentrated on the No. 1 and No. 5 fault zones in the Shunbei area. Due to the complex geological structure, there are a series of drilling technical problems in drilling. Lost circulation will not only lose drilling fluid, produce non-productive time and affect drilling safety, but also limit drilling speed, which is one of the most headaches and difficult problems in drilling. To this end, scholars at home and abroad have carried out a lot of research and exploration, and developed a series of leak-proof and plug-in devices such as non-penetrant, elastic graphite, Form-A-block, fiber cement, water-absorbing resin, thermosetting resin, gel and chemical consolidation. Materials, and formed a variety of supporting process technologies. Granular, fibrous, and sheet composite bridging materials are most commonly used on the site, but ordinary bridging materials are resistant to temperature differences, easily carbonized at high temperatures, and the width of underground cracks needs to be clear when plugging, non-penetrants prevent Lost circulation of microfracture formations. It has poor leak-proof effect on large cracks, because of its low strength, expansion materials such as water-absorbent resin are better for plugging, but the pressure-bearing effect is poor, foreign Form-A-block and Chinese DTR are equivalent High water loss materials have good adaptability to cracks, but the pressure is generally low, fiber plugging methods such as fiber cement and thermosetting resin are complicated in process, high in risk and high in cost, gel plugging technology has good adaptability to plugging, but withstands temperature differences If it is not combined with other materials, it is easy to leak again in the later period due to the decrease in gel strength, chemical consolidation plugging technology has a high success rate in plugging, but the plugging construction time is relatively long. In summary, although great progress has been made in leak prevention and plugging technology at home and abroad, there is less research on igneous rocks, and it cannot meet the needs for leak prevention and plugging in igneous rock formations. Therefore, it is necessary to analyze the second Shunbei Oilfield in depth. Lost circulation characteristics of igneous rocks in the Mesozoic and the difficult points of preventing Lost circulation and plugging. Develop effective materials for preventing and plugging Lost circulation to improve the effect of preventing and plugging.