页岩气水平井固井面临三大技术难题：①大型体积压裂对水泥环及井筒密封性能

Shale gas horizontal well cementing faces three major technical problems: ① Large volume fracturing requires high sealing performance of the cement ring and wellbore; ② It is difficult to improve the flushing displacement efficiency under the condition of high-density oil-based drilling fluid; ③ Long horizontal section casing It is difficult to center the pipe and ensure the casing. Through tackling key problems, the mechanical performance indicators to ensure the sealing of the cement ring have been put forward, and the high-strength and toughness cement and the high-efficiency flooding prefluid system that meet the fracturing conditions have been developed, forming a complete set of shale gas horizontal well cementing technology, effectively guaranteeing Improve cementing quality and cement ring sealing performance.

Shale gas horizontal well cementing wells face three major technical problems: (1) large-scale body backlog cracking on the cement ring and wellhead sealing performance requirements are high; Through the research, the mechanical performance index to ensure the sealing of cement ring is put forward, the system of high-strength toughness cement and high-efficiency oil-repellent pre-liquid under fracturing conditions is developed, and the shale gas horizontal well cementing complete set of technology is formed, which effectively guarantees the cementing quality and cement ring sealing performance.

There are three technical difficulties in cementing shale gas horizontal wells: 1) large volume fracturing requires high sealing performance of cement sheath and wellbore; 2) it is difficult to improve flushing displacement efficiency under high density oil-based drilling fluid; 3) it is difficult to run casing in long horizontal section and ensure casing centering. Through tackling key problems, the mechanical performance index to ensure the sealing performance of cement sheath is put forward. High strength and toughness cement and high-efficiency oil displacement pre fluid system are developed to meet the fracturing conditions. A complete set of cementing technology for shale gas horizontal wells is formed, which effectively ensures the cementing quality and sealing performance of cement sheath.<br>