Wellhead Protective Measures During Well Stimulation Operations; Current Limitations and New Horizons

Abstract Wellhead and production trees are the primary safety barriers on any gas, oil and water wells. Such wells may require flowing corrosive or abrasive fluids through the permanent wellhead components as part of well stimulation to restore well productivity. This paper describes the limitations of the available methods to protect wellhead equipment during acid stimulation jobs and proposes a new solution that will provide the required protection and field operation optimization. Current wellhead protection solutions during well stimulation activities fall under two methods; utilizing sacrificial equipment during well stimulation or utilizing tree savers on permanent wellhead equipment. Both approaches have their drawbacks. The former involves additional operational cost to install and remove the sacrificial equipment. Furthermore, well securement involves killing the well which will diminish the effectiveness of the stimulation job. The latter utilizes proprietary technology that is limited by well completion size and does not offer protection for all production tree sizes. The proposed solution involves setting an isolation sleeve across the permanent wellhead equipment. A sacrificial set-up is installed on top of the permanent production tree to facilitate isolation sleeve installation, well stimulation activities and maintain well control requirements. The sleeve will be retrieved and the sacrificial set-up removed once the stimulation operations are concluded. This technology bypasses the limitations of the available methods. It provides full protection from the production tree to the tubing hanger from abrasive fluids pumped and pressure during well stimulation jobs. Furthermore, it does not require killing the well to remove the sacrificial set-up resulting in optimizing rig operations and maximizing the benefit of well stimulations. Finally, it has no limitations to production tree size unlike the existing solutions. The methodology presented in this paper provides a novel solution to ensure complete protection to the wellhead equipment during well stimulation, minimize operation cost and bypass the current limitations from the available solutions in the market.