Wells in the Vaca Muerta field have consistently hosted an array of technical challenges from downhole conditions in the extended lateral section, including casing collapse or restrictions developed during the hydraulic fracturing phase. With these factors in mind, an initiative was made to implement key operational parameters to improve efficiency during Coiled Tubing (CT) operations without sacrificing (Health, Safety, and Environment) HSE or (Service Quality) SQ during the completion life cycle associated with unconventional activities. Operational optimizations based on ongoing diagnostic, design and delivery of CT well interventions are shown in this paper through a chronological compilation of 45 wells in 12 pads. Initially, CT milling job times were defined based on the minimum and maximum speeds while running in and pulling out of the hole, circulation fluid parameters to ensure turbulent flow and parameters for gel sweeps and wiper trips. Subsequently, a series of reviews of the data collected from operations was implemented, and the focus was shifted to operating times at the different job stages. This was followed by stream mapping the personnel and equipment assigned to each specific activity. Additionally, Key Performance Indicators (KPIs) were defined, such as CT speed between the surface and the kick-off point, average speed between plugs, plug milling time, and time to return to surface while pulling out of the hole. This journey to efficiency has been achieved by systematically introducing continuous improvements into our operations, utilizing on-site field personnel as the main driver and the engineering team as support, monitoring the execution, and taking action when needed. After servicing 45 wells across 12 locations over two years, an 11% reduction of the total time in the well during frac plug mill out has been achieved. Considering that the lateral length of the wells and the number of stages has increased by 52% and 41%, respectively, this has enabled significant cost savings in a safe and effective way. Operational efficiency has to be aligned with contemporary advances in the industry. As completion strategies evolve, so must our intervention methods. This paper documents how the completion life cycle of wells in a challenging, unconventional environment has been reduced through customized well interventions with CT.

In low-permeability formations, natural fractures, fissures, and other geologic heterogeneities are important considerations in the design of hydraulic-fracture treatments. In some formations, it is considered beneficial to capitalize on these conduits to establish a greater network of connection to the reservoir. In the Bakken shale, near Westby, Montana, a simple planar fracture was desired because complex fracture growth could result in connectivity to a zone of nonproductive interest and led to the following issues:• Higher rates, which could result in extreme fracture complexity and limited fracture extension.• Inability to effectively place proppant for conductivity.• Excessive fluid leakoff caused by high net pressures requiring large pad volumes.• Connection to water-producing zone.• Less aggressive proppant schedule because of likelihood of screenout.• Increased cost, footprint, personnel, and equipment on location.With an understanding of the formation-rock properties, stresses, and the natural fracture system, the treatment design parameters were established to help ensure lower treatment pressures and optimum fracture extension in the zone of interest. This paper presents the successful execution of a multi-interval fracture-stimulation treatment for a long-lateral horizontal completion in the Bakken shale using a state-of-the-art hybrid coiled-tubing (CT) system and hydrajet-assisted fracturing (HJAF) technology. The new approach incorporated the following technology:• Low-rate treatment schedule.• Multiple-fracture stimulation treatment.• Aggressive proppant-treatment schedule.• Higher gel viscosity to encourage desired fracture growth and proppant transport.• Hydrajet perforating.• Dynamic fluid diversion to isolate treatment to intended zone.• State-of-the-art hybrid CT system.