Abstract
This paper presents the implementation of explosive-free hydromechanical perforation technology, run on pipe during plug and abandonment P&A operations, connecting the annulus between casings using blades that cut without affecting the integrity of the external casing and subsequently circulate cement slurry through the perforations in order to establish an effective transverse barrier, mitigating the risk of fluid migration from the wellbore to the external environment.
During P&A operations in some fields in Colombia, there are explosive mobilization restrictions, and it is required to perforate the casing to connect the annulus without affecting the external casing to pump a cement plug as an effective transverse barrier. According to this, an alternative to conventional perforating was planned. The hydromechanical perforating technology was implemented in 2 pilot wells with 5-1/2″ and 6-5/8″ production casing, achieving a perforated flow area necessary to circulate a cement slurry to obtain homogeneous returns on surface, and thus placing a barrier that prevents the migration of the fluid from the well to the external environment.
The implementation of the explosive-free hydromechanical perforation technology was successfully carried out in 2 wells for abandonment that had no cement close to surface in the B annulus. The result was an optimization of operational time due to the possibility of activating the tool multiple times in a single run compared with additional wireline runs until circulation on surface is verified. The jobs were performed with no HSE incidents or Not Productive Time, reducing logistics for explosive mobilizations restrictions, and eliminating explosive handling risks and the requirement of a wireline unit. The final schematic after the definitive Plug and Abandonment (P&A) includes on surface an effective cement barrier that covers the inside of the production casing and the annulus between casings, without affecting the integrity of the external casing and preventing contamination of the external environment due to well fluids migration.
The Hydromechanical Perforating Technology is a new option that provides a safer connectivity alternative that replaces explosives and, guarantees that the integrity of the external casing is not affected. Additionally, multiple activations in a single run can be performed until circulation is established to clean the annulus prior to circulating the cement slurry.