Innovative Process to Ensure Efficient Multiple Stage Fracturing Treatments

Abstract Multiple-Stage-Fracturing (MSF) is a common practice today as it allows controlling the stimulation of long intervals, and improves the ultimate recovery of hydrocarbons. Multi-Stage-Frac-Completions (MSFC), designed with Open-Hole-Packers (OHP) and Frac-Ports (FP), are currently implemented by Saudi Aramco to perform such operations in gas wells. The integrity of the OHP and the functionality of the FP are vital for an effective fracturing treatment. During a MSF treatment, the bottom FP is opened first by pressurizing the MSFC to a predetermined pressure. After pumping the first fracturing stage, a ball is dropped to isolate the lower zone, open the second FP with pressure, and enable the second fracturing stage. This step is repeated till all FP are opened and corresponding zones are fracced one after the other. In every step of pressurizing the MSFC, a drop in pressure is automatically interpreted by the assumption that the adequate FP is open and that the MSFC is ready for another fracturing stage. The OHP are also assumed to be holding without performing any downhole checks. Opening the wrong or multiple FP at the same time, having a leaking OHP will certainly lead to undesired results and possible expensive remedial rig interventions. Therefore downhole monitoring is needed to confirm that the MSFC is ready before every fracturing stage. The Fiber-Optic-Enabled-Coiled-Tubing (FOECT) can be used as monitoring system by measuring the Distributed-Temperature-Survey (DTS), which is interpreted realtime to confirm which FP is open, and if OHP are sealing. This paper demonstrates through two case studies how DTS was used to assess the readiness of the MSFC to proppant fracturing treatment. An innovative profiling process in MSFC is proposed to replace assumptions by measured facts, to give client confidence on when to start the fracturing treatment, and to eliminate unnecessary operation by detecting MSFC hardware malfunction.