Research and application of multistage fracturing technology using an immobile string in full wellbore with falcon grooves

Key words:  falcon groove sliding sleeve  immobile string  full-bore  erosion  pressure loss

Abstract:

In multiple fracturing using immobile string, ball-throwing sliding sleeves are normally adopted with progressively reduced ball diameter, which can limit the number of fracturing stages and the pumping rate of fracturing fluid, restricting multi-stage and large-scale of well-fracturing. In this paper, the design concept of "circumferential grading" was put forward. With the use of the falcon wing switch and the sandblast packer with falcon groove, the non-shrinking throttling in the fracturing tubing was realized. The arc-shaped baffle diversion structure was optimized by the numerical simulation method. Through the numerical simulation of the inner flow channel structure of the tool, a calculation formula for the pressure loss of the sand-carrying liquid suitable for the sliding sleeve structure was obtained. The field test results show that there is only slight erosion inside the sliding sleeve with arc baffle guide structure, which improves the anti-erosion ability of the tool. The maximum value of the relative error between the calculation formula and the pressure loss result obtained from the field test is 13.26%, which is convenient for engineering application. Based on the stepwise full-bore falcon groove sliding sleeve tools, through the research of supporting tools and process technology, the fracturing stage and displacement had been improved, which provided a new technology for multistage fracturing with the full-bore immobile string.