Page 394 - Fundamentals of Gas Shale Reservoirs

374 GAS SHALE CHALLENGES OVER THE ASSET LIFE CYCLE

Frac sleeves with ball seats

Casing packer

Openhole packers
FIGURE 17.9 Ball‐activated completion system (Source: Baker Hughes).

Frac fluid flow
in annulus
Frac sleeves

Coiled tubing Packer

FIGURE 17.10 Coil tubing–activated completion system (Source: Baker Hughes).

TABLE 17.3 Summary of benefits and consideration
Plug‐and‐perf Ball‐activated Coil tubing activated
Number of stages Virtually unlimited Limited Virtually unlimited
Stage placement Flexible Fixed Fixed with frac sleeves flexible with SJP
Contingency options Full diameter Diameter restrictions Full diameter and CT in hole
Fracturing logistics Pressure pumping, wireline, CT Pressure pumping Pressure pumping, CT
Fracturing ops efficiency Rig up/down between stages Nonstop Brief frac shut down between stages
Post fracture Mill out plugs Restricted diameter Full production diameter

concerning operational efficiency, cost, logistics, flexibility, depending on the economics and availability of services.
and application. Simultaneous operations can be utilized in some applica-
Plug‐and‐perf has a distinct advantage during the tions to optimize plug‐and‐perf completions. If two wells
appraisal phase. The stage placement has not been locked are spaced close enough together, wireline can be operating
into place until the perforation gun has been fired into the on one well while pressure pumping is operating on the
liner string. If it is determined that a stage needs to be moved other. When both operations are complete, the services
to another location along the lateral, it is simply a matter of switch wells and minimize the nonproductive time for
moving the perforations to that depth. This allows time for both wireline and pressure pumping (a simultaneous frac
data gathering and changing the stage placement on the fly, operation).
if required. There is, however, a lack of efficiency during the Ball‐activated systems are primarily used for completion
fracturing process, because of rigging up and rigging down optimization, because of the efficiency and logistical bene-
of wireline and pressure pumping equipment between each fits during the fracturing process. These systems are simpler
stage. When operators move into the development phase, it from a logistical point of view, because pressure pumping is
is the time to focus on more efficient completion techniques, the only service that is required on location. Also, the frac