Mega Reach Case Study, Saudi Arabia; The Application of Fluidic Oscillation Vibratory Tools in Tackling a Challenging Coiled Tubing Well Intervention

Abstract

Every year, the complexity of horizontal wells grows, and matrix stimulation of these wells is key for maintaining production levels and improving the draw-down from producing formations. In the subject field, many wells are drilled as mega-reach with measured total depths up to 33,000 ft. The mega-reach represents a significant challenge for coiled tubing to reach the total depth (TD) and perform well interventions such as stimulation and logging. Coiled tubing (CT) may lock up before TD, and it can be challenging to understand the root cause. One difficulty is differentiating between lockups due to the well conditions and bottom-hole assembly (BHA) malfunctions. Electric submersible pump (ESP) completions contain bypass assemblies that impose an additional challenge introducing a restriction in tubing internal diameters. The restriction is less than 2.50" in the completion, increasing to 8-1/2" for the open hole, extending for at least 5,000 ft laterally in the producing formation. With the large variation in internal diameter (ID), the hydraulic tractor option is excluded from the mega-reach aid list, though it has proven reliable in extending the reach of CT for 6-1/8" openhole sizes in the same field. Therefore, the challenge here is to derive the maximum output possible from fluidic oscillation vibratory tools to achieve forces close enough to tractor forces and ultimately accomplishing the intervention objective. A combination of mechanical and chemical solutions was the designated approach to tackle the challenge. After reviewing all the possible solutions, tractors were excluded due to the extreme expansion ratio needed resulting in lower pulling forces. A fluidic oscillation tool inducing axial vibration of an absolute magnitude exceeding 1,600 lbf was yard tested and deployed as a solution in combination with a selection of friction and drag reducers. This paper will illustrate the reach challenges, analysis performed, and show how we could utilize the latest developments in fluidic oscillation vibratory tools. It will also include downhole real-time data acquisition assisting the understanding of lockup occurrence, as well as quantifying the improvements in the pre-job tubing force model simulation.