First High-Rate Stimulation Treatment Through Coiled Tubing with Real-Time Downhole Monitoring—A Story of Success

Abstract

Over the last 10 years, matrix stimulation of multilateral wells has been one of the most fascinating and technology-driven interventions in the oil and gas industry due to the several challenges involved in this kind of operation. Overcoming these challenges, which include lateral identification and accessibility, reservoir assessment, and accurate placement of stimulation fluids, has encouraged operators and manufacturing and service companies to develop innovative techniques and novel technologies. In Saudi Arabia, coiled tubing (CT) equipped with real-time downhole measurements and a multilateral identification tool (LIT) has been one of the most valuable technologies to enhance the interventions in multilateral wells. Initially, the ability to monitor real-time data enabled a more efficient operation of the LIT, as well as optimizing and properly placing the stimulation treatment fluids by avoiding the identified high-intake zones across each lateral. Most recently, the incorporation of gamma ray tool into the real-time downhole measurements package allowed a faster identification of each lateral and accurate depth correlation for pinpoint acid stimulation; nevertheless, when this technology was deployed, pumping rates were significantly limited to a maximum of 2.0 bbl/min due to limitations on downhole tools and optical fiber installed inside the 2 3/8-in. CT. In some cases, this barrier also represented a drawback for optimum fluid penetration and efficient diversion across the zone of interest during the stimulation treatment. This paper documents the first worldwide applications of the enhanced version of a real-time downhole measurements package deployed on 2 3/8-in. CT for the successful matrix stimulation of a multilateral power injector well in Saudi Arabia, where the barrier of 2.0 bbl/min was far exceeded while maintaining intact all downhole readings. The operation represented a significant increase in operational efficiency and set a new record for this technology. A total of 4,585 bbl of stimulation fluids were injected across the open hole laterals (7,685-ft combined on both wells) at maximum rate achieved of 4.6 bbl/min, which were successfully accessed with the use of the LIT in a single run without the need to pull out the CT to surface. The use of enhanced the real-time downhole measurements package reduced the operational time by almost 50%, enabled more effective formation damage removal by injecting stimulation fluids at a higher rate, provided real-time depth correlation, verified access via gamma ray to each lateral without the need to tag total depth, and resulted in a tangible cost reduction.