Maximizing well production in unconventional reservoirs has long been a challenge. Standard sleeves and traditional methods have limitations and obstacles, including the number of stages, isolation method used, and well stimulation rates needed – all of which place severe limits on accessing reservoirs, optimizing stimulated reservoir volume, and maximizing production levels.
Elect? frac sleeve is a monobore, cementable, solution that offers unlimited stage counts in multistage fracturing operations and minimal inside-diameter (ID) restrictions in order to optimize contact with the reservoir. The Elect frac sleeve is the only electronic frac sleeve on the market that can be reliably cemented in a well. By enabling unlimited stages in multistage fracturing operations, the compact Elect sleeve helps eliminate the risks and effects of using conventional ball-drop-activated and coiled-tubing-activated frac sleeves. With numerous functional options, operators can leverage the tool’s capability to dramatically increase recoverable reserves while also decreasing operational costs per BOE.
Elect frac sleeves enable operators to:
Overcome stage count limitations
Mitigate over-displacement
Optimize reservoir access and stimulation
Enable pinpoint stimulation
Reduce service intensity and risk
Decrease completion cycle time
These frac sleeves are available in three variations: single-entry (SE) and multi-entry (ME) sleeves, and toe sleeves.
ELECT SINGLE-ENTRY FRAC SLEEVE
The Elect SE sleeve is a cementable frac sleeve with a full-wellbore inside diameter (ID) that allows for an unlimited number of stages. A single-sized ball is used to activate and treat the sleeves. By removing the flow restrictions present with conventional frac sleeves, there are no longer any rate or pressure limitations. The use of dissolvable ball technology helps eliminate the need to perform a millout or cleanout operation.
ELECT MULTI-ENTRY FRAC SLEEVE
The Elect ME frac sleeve is similar to the SE version, except that it does not provide isolation. Instead, this delayed-opening sleeve is used, along with the SE sleeve, as an additional cluster (entry point) in a stage.
ELECT TOE SLEEVE
The Elect toe sleeve allows for true operational pressure independence. Because the tool acts like a piece of casing for a pre-programmed amount of time, there is no need to pin the tool for pressures typically encountered, such as running in hole, fluid displacement, or setting a tool like a liner hanger. Once the pre-programmed timer elapses, the sleeve will open when a predetermined pressure is achieved.
FEATURES
??Battery-powered electronics
??Programmable features
? Full-wellbore ID
? Ability to transform from a piece of casing to a fully functional sleeve
BENEFITS
? Removes the need for intervention
? Reduces complications with cementing and rate limitations
? Performs reliably in complex frac geometries
? Overcomes stage count limitations
? Minimizes risk with operational pressures
? Compresses completion cycle time
Case Study
In an East Texas Cotton Valley horizontal well, Rockcliff Energy set out to validate the newly released Halliburton electronic Elect? monobore toe sleeve system. The Elect system is the only electronic frac sleeve on the market that can be reliably cemented in a well. Rockcliff Energy wanted to evaluate this innovative technology to see if it would be a viable solution for significantly reducing time and risk on future applications.
Rockcliff Energy was interested in a frac sleeve system without operational pressure limitations to allow for higher circulating and cementing rates, and to help eliminate the risk associated with wellbore packoff and the inadvertent shearing of pins.
A further limitation with conventional toe valves is determining an ideal pinning configuration that resists operating pressures from running in hole, cementing, performing casing pressure tests, and running another completion tool such as a liner hanger. Halliburton worked with Rockcliff Energy to create a plan for running a new technology that would create this value without introducing risk into the completion.
The Elect monobore frac sleeve system is a platform of electronically powered equipment that actuate to turn simple casing into smart completion tools. The Elect toe sleeve system does not utilize shear pins to resist operating pressure in the wellbore. Instead, it uses an electro-hydraulic lock that unlocks after a predetermined, programmed amount of time. This allows the use of operating pressures that approach the limitations of the casing prior to unlocking. Further, the fullbore drift provides the ability to run high-efficiency wiper plugs and pass tools through the sleeve without risk of becoming stuck.
The Elect toe sleeve system was run in hole, along with the Halliburton RapidStart? Initiator CT (Casing Test) toe sleeve, which is a reliable, field-proven toe sleeve that allows for a casing pressure test for an extended period of time before the sleeve opens. This minimized the risk of the field trial, as it allowed for the Elect frac sleeve to be actuated and given a chance for validation before having the RapidStart Initiator CT toe sleeve act as a contingent solution.
The Elect toe sleeve system was programmed with an actuation time of 197 hours and pinned for an opening surface pressure well below that of the RapidStart Initiator CT toe sleeve. Both tools were successfully run in hole and cemented, thus validating the ability of the electro-hydraulic lock to withstand standard operating pressures.
Approximately 18 hours before the Elect toe sleeve system was programmed to actuate, a successful casing pressure test was performed at 9,000 psi, 5,000 psi above the pinned pressure of the Elect frac sleeve. This validated that the electro-hydraulic lock could withstand the pressures associated with casing pressure tests.
Approximately two hours after the Elect toe sleeve system was programmed to actuate, pressure was applied to open the Elect frac sleeve. It successfully opened within the desired range. Due to the large variance between the Elect toe sleeve and the RapidStart Initiator CT toe sleeve pinning pressure, establishing injection at the lower pressure validated that the Elect sleeve was the one that opened.
A revolutionary step in unconventional completions is the successful test of an electronic frac sleeve without operational pressure restrictions from running in hole, cementing, and performing casing pressure tests during a programmed time window, followed by successfully opening the tool after the timer had elapsed.
Not having to rely on mechanical measures to hold back operating pressures significantly reduces the risk and time involved with field personnel and engineers planning how a frac sleeve is dressed and run in hole. The Elect frac sleeve also allows for more complex completions in the future, where operational pressures may be higher than available pinning pressures or where high pressures may be encountered unexpectedly due to wellbore conditions.
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