Perforating Gunshock Loads - Prediction and Mitigation

Abstract

Perforating wells calls for careful planning to maximize well productivity over the life of the well, and to prevent time and money losses due to unexpected side effects. A large class of wells and in particular high-pressure wells are susceptible to gunshock damage when they are perforated with inappropriate gun systems. This paper presents applications of a simulation methodology to predict gunshock loads for tubing-conveyed and wireline-conveyed perforating jobs. With this simulation methodology we can evaluate the sensitivity of gunshock loads to changes in gun type, charge type, shot density, cable size, tubing size and length, number of shock absorbers, rathole length, placement and setting of packers, and early reservoir response, among many others.When planning perforating jobs, engineers strive to minimize the risk of equipment damage due to gunshock loads. With the simulation software presented in this paper, engineers can identify perforating jobs with significant risk of gunshock related damage, such as unintentional pull-offs, bent tubing and unset packers. When predicted gunshock loads are large, changes to the perforating equipment or job execution parameters are made to reduce gunshock loads to an acceptable level.Fast gauge pressure data from perforating jobs shows that wellbore pressure transients can be accurately predicted. For well prepared simulation models, typical peak sustained pressure amplitudes at the gauges are on average within 10% of simulated values. In jobs where shock absorbers were used, residual deformations of crushable elements correlate well with predicted peak axial loads; which confirms that gunshock loads on the equipment are well predicted.With the simulation methodology described in this paper engineers can evaluate perforating job designs in a short time, and they can optimize perforating jobs by reducing gunshock loads and equipment costs. The ability to predict and mitigate gunshock damage in perforating operations is very important because of the high cost of typical high-pressure wells.

Numerical Simulation Study on the Damage Mechanism of the Combined Perforating Well Testing Tubing in Ultra-Deep Wells

“…The challenge of addressing tubing safety issues remains difficult. Utilizing numerical simulation, a widely applied computer technology in engineering [23,24], allows for the comprehensive simulation and calculation of the entire perforation process.…”

Análise técnico-econômica do canhoneio de poços do pré-sal brasileiro utilizando diferentes métodos de condução do canhão.

“…In addition to the Formation Testing capability, the mechanical strength of the tubing will ensure the integrity of the system when it is submitted to the high forces of the gun blast. The shock caused by the detonation of these extensive gun strings might break a wireline cable or bend a coiled tubing if the job is not carefully planned (BAUMANN et al, 2013). In the TCP technique mentioned, the overbalance is achieved by keeping the drilling or completion fluid in the wellbore.…”

“…Fast gauges combined with pressure and temperature sensors will provide the details of the perforated zone response right after the detonation(GUEDES et al, 2019). The comparison between the simulated and the actual values can be done while still pulling the gun out of the hole(BAUMANN et al 2013).…”