Although the main objectives of drillstem testing (DST) have remained largely unchanged over the years, operators are continuously seeking a means of improving operational efficiency (time/cost savings) while maintaining the highest level of operational standards, with safety and the environment being paramount. This paper presents a case history of the first retrievable dual packer testing string used to independently test two reservoirs in a single trip (toolstring conveyance into and out of the hole), which enhances operational efficiency. This case history is from an offshore exploratory well in Saudi Arabia in which a dual retrievable packer test string was deployed with a real-time telemetry system to successfully test two independent reservoirs in a single trip. Throughout the operation, real-time telemetry data above and below each packer enabled real-time understanding of the operational process and provided assurance of equipment/process integrity before proceeding with the next sequence of well testing operations. In this manner, operations were safely performed step-by-step, ensuring that the well test objectives and zonal isolation were met to determine the individual reservoir evaluation integrity. With the application of acoustic telemetry technology, the ability to acoustically communicate with and control downhole tools in real time is achieved. Communication to and from the downhole tools also provides the status of the downhole equipment in real time. In addition, knowledge gained from the real-time data enhances the ability of the operators to perform well tests with reduced uncertainties. The early availability of reservoir knowledge enables operational efficiencies, ensuring that test objectives are met, and may reduce the overall test period and significantly reduce well testing costs. The direct result of eliminating multiple trips is that operational efficiency is achieved, enabling the operator to save time and money without compromising data quality or health, safety, and environment standards. This case history represents a milestone for the industry, demonstrating the successful deployment of multizone testing, and serves as a stepping stone for even greater efficiencies by using real-time telemetry technology. This paper also discusses lessons learned and plans for additional well testing process efficiencies, enhanced with well application selection and DST toolstring acoustic control devices and technology.
Drill Stem Tests (DSTs) in exploratory wells are important for production planning, for identifying the characteristics of oil and gas, and to assess the commercial viability of the entire reservoir. A new generation of downhole test tools has been developed to address the growing challenges of reservoir testing and evaluation in the deep and ultra-deep-water environments now being explored; these new tools maintain safety as paramount and strive for greater testing efficiency in the acquisition of the reservoir information being sought in nearly all evaluation and exploration wells today. There is a growing need to better understand each well in real time as it is being tested, not only concerning the reservoir itself, but also the downhole tool mechanics critical to the testing operation. This knowledge helps to reduce uncertainties of downhole conditions, and also, helps to ensure that operations are being carried out in a safe manner and as planned. With the improvements in operational efficiency, savings in rig time also can be gained.With the application of acoustic telemetry technology, the capability to acoustically communicate and control downhole tools in real time is achieved. Real-time data can be transmitted to and from the downhole tools, allowing on-demand control of well testing operations. The acquisition of real-time gauge data with the additional capability to actuate a new combination tester and circulating valve provides enhanced control of a DST and can provide the operator with ongoing feedback of tool position and status. This enhances the operators' ability to perform the well test with reduced uncertainties. Extending the real-time acoustic system to tool control provides the operator with additional capabilities. The operator can control downhole tools without using annulus pressure, which is not possible with the traditional DST tool systems operated with annulus pressure that restricts the number of different tools used for a DST due to casing pressure limitations. Acoustic-telemetry-controlled tools are not limited in function or number.This paper discusses a case history in a deepwater, pre-salt area in Brazil where a new acoustictelemetry-operated tester valve was used to successfully perform DST testing operations. This paper also discusses the new possibilities that this new tool can bring to well testing.While the main objectives of a DST are basically the same, this new tool enables downhole well-test tools to advance to a new generation of equipment that is designed to optimize time, streamline decision making, minimize environmental and operational risks; and ultimately, help maintain safety as a priority.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.