Abstract
A ball-activated sliding sleeve design for multistage cemented lateral completions has been developed that allows multiple frac sleeves to be opened using the same diameter ball, significantly increasing the total number of sleeves available in the completion design. This paper discusses the sleeve design, the challenges associated with cemented laterals, the results of initial field installations, and the ramifications for completion design and execution.
Ball-activated sleeves were introduced to overcome limitations of plug and perf designs and facilitate longer and more complex completions. As these completions have evolved, the technology has reached inherent design limitations. This is especially true in cemented lateral completions. These installations require a series of incrementally smaller balls and ball seats that reduce wellbore ID and ultimately limit the total number of sleeves that can be used in the completion.
To further extend lateral length and accommodate the cemented laterals, a sliding sleeve device has been developed that allows multiple sliding sleeve valves to be opened with the same size ball and seat. The sliding sleeve design allows up to 90 individual sleeves to be opened as a single point of entry completion without dropping a ball diameter smaller than 4.00-in. in 5.500-in. casing, or a 3.25-in. ball in 4.500-in. casing. This increases wellbore ID over the length of the completion, and increases the total number of sleeves or sleeve clusters that can be employed in the completion design. The higher number of available sleeves affects the completion design, whether it uses single sleeve per stage or clusters of sleeves. In addition, lateral length of the completion is not constrained by the number of sleeves or the reach of coiled tubing.
Cemented installations in the US Marcellus, Utica Shale, and Spraberry plays have enabled single-point-of-entry stimulations that optimize hydraulic fracturing pressure and provide a focused frac. In some applications, this has reduced pump rates and surface horsepower requirements by as much as 50% and also reduced the overall frac time. Experience also indicates these completions reduce water requirements by minimizing over-flushing of the formation. These cemented installations illustrate the potential of continued changes in completion designs and the viability of longer laterals.
This paper is the first published examination of field performance in the initial installations of the sliding sleeve technology. Field results and data from sleeves installed in Marcellus, Utica Shale, and Spraberry completions are presented. Based on performance in these applications, the paper reviews completion design considerations facilitated by the ability to install larger numbers of sliding sleeves over longer cemented laterals.
