A good design of a multistage-fracture (MSF) treatment must be implemented effectively to ensure expected production from a fracture treatment. Knowing that downhole tools are correctly deployed and function as planned in MSF, therefore, is important. The setting of packers, opening and closing of frac ports, shifting of frac sleeves, and isolating with ball drops in openhole assemblies are some of the many major events that need to be monitored closely to ensure smooth operations. As such, wellbore pressure is monitored at surface and is the primary method for determining if tools are functioning properly and if the stimulation program is being executed correctly. As wellbores become longer, numerous fracturing stages are conducted on a single wellbore, and multiple service companies are involved on site to support a successful stimulation program, pinpointing issues or challenges when they arise becomes more difficult—particularly if the pressure signature is unclear, hard to interpret, or not present at all. These ambiguities can lead to treatment uncertainty, costly delays, or huge remedial efforts. Being uncertain and missing out on a few stages in the treatment can have major effects on production, ultimate recovery, and the overall field-development plan.
A new real-time-visualization (RTV) technology combined with high-resolution pressure reading and acoustic sensors is being used to overcome operational difficulties and to optimize stimulation efforts by reducing uncertainty. The RTV technology has a minimal surface footprint, can be deployed rapidly, is self-contained, and does not interfere with concurrent on-site operations. The use of this technology significantly improves the entire fracturing process, thereby optimizing well production.
RTV has been used in more than 10 countries, proving to be an effective tool for confirming successful operations or expediting the troubleshooting of operational issues. In one case, an operator was facing challenges in establishing connectivity with the reservoir when a toe sleeve failed to open. The RTV and acoustic system provided the operator valuable insight; the problematic sleeve was identified and opened with a coiled-tubing-deployed ball-seat activator immediately, preventing a remedial operation of milling out the entire completion system, which would have been very costly.
RTV has also been used offshore. Monitoring an openhole multistage stimulation system that was using ball-activated sliding sleeves, the RTV system confirmed all critical events, such as ball launches, landings, and sleeve shifts. The system prevented unnecessary use of extra balls or coiled tubing in cases where the pressure signature of sleeve shifts was not present.
Although many technologies and approaches are available to help with real-time monitoring and troubleshooting, incorporating this RTV system provides critical data to correct issues effectively and improves operational efficiency, giving operators greater confidence in decisions relating to downhole events.
This Month's Technical Papers
Distributed Temperature Measurements Allow Fracture Diagnostics During Flowback
Multiple-Source Data Provide Insight Into Hydraulic Fracture Geometries
Advancing Production Flow Profiling With Subatomic Fingerprints and Big Data Analytics
| Zillur Rahim, SPE, is the president of Rahim Petroleum Technology based in Houston, where he consults with operators and service providers on well completions and hydraulic fracturing technology. His current work includes joint projects with Aramco Americas on new-technology application and optimization of completions and stimulations. Before starting his own company, Rahim was a principal petroleum engineering consultant with Saudi Aramco’s Gas Reservoir Management Department, where he was responsible for the development of Saudi Arabian nonassociated-gas reservoirs. He also worked with Stephen A. Holditch and Associates on tight-gas-reservoir optimization and hydraulic fracturing. An active member of SPE, Rahim has authored more than 120 technical papers and has participated as cochairperson, session chairperson, technical committee member, discussion leader, forum coordinator, and workshop organizer for various international SPE events. He holds a BS degree from L’Institut Algérien du Pétrole, Boumerdès, Algeria, and MS and PhD degrees from Texas A&M University, all in petroleum engineering. Rahim, a licensed professional engineer in Texas, serves on the JPT Editorial Committee and can be reached at zillur.rahim@petrorahim.com. |
