Ball sealer tracking and seating of temporary plugging fracturing technology in the perforated casing of a horizontal well

Abstract

Multistaged temporary plugging fracturing in horizontal wells is an emerging technology to promote uniform fracture propagation in tight reservoirs by injecting ball sealers to plug higher-flux perforations. The seating mechanism and transportation of ball sealers remain poorly understood. In this paper, the sensitivities of the ball sealer density, casing injection rate and perforation angle to the seating behaviors are studied. In a vertical wellbore section, a ball sealer accelerates very fast at the beginning of the dropping and reaches a stable state within a few seconds. The terminal velocity of a non-buoyant ball is greater than the fluid velocity, while the terminal velocity of a buoyant ball is less than the fluid velocity. In the horizontal wellbore section, the terminal velocity of a non-buoyant or buoyant ball is less than the fracturing fluid flowing velocity. The ball sealer density is a more critical parameter than the casing injection rate when a ball sealer diverts to a perforation hole. The casing injection rate is a more critical parameter than the ball sealer density when a ball sealer seats on a perforation hole. A buoyant ball sealer associated with a high injection rate of fracturing fluid is highly recommended to improve the seating efficiency.

A Boundary-Element Analysis of Crack Problems in Multilayered Elastic Media: A Review

“…Among various numerical methods for the analysis of the crack problems to compute crack opening displacement, the boundary element method (BEM) is widely chosen, because it only discretizes boundaries of a domain of interest and consequently enables a more-efficient computation and a more-convenient implementation [34][35][36][37], while most of the other methods, such as the PFM or FEM, require discretization of the whole domain [31]. Furthermore, the BEM exploits existed analytical fundamental solutions, ensuring a potentially more accurate computation [38][39][40][41].…”

Temporary Plugging Agent System for Thermally Induced Phase Change Fracturing in Shale Gas Reservoirs

“…Generally, a remote delivery device needs to be installed separately during the construction of the temporary plugging ball, and it needs to be delivered manually. Moreover, the migration distance of the temporary plugging ball fracture is short of the formation, and most of it acts on the fracture opening or in the middle. − Most of the common gel-type temporary plugging agents use a gel breaker to break the gel. , This gel breaking method causes great damage to the reservoir, and the gel breaking time should not be controlled. , The autonomous thermal degradation of the gel at reservoir temperature is the development trend of the gel temporary plugging agent. Compared with the temporary plugging ball, the supramolecular gel temporary plugging agent can simplify the construction method, and by entering the far end of the fracture to achieve temporary plugging in the deep part of the fracture, it can improve the construction efficiency, increase the complexity of the fracture, and prevent well channeling.…”