Proppant Selection and Its Effect on the Results of Fracturing Treatments
Performed in Shale Formations
Since the introduction of hydraulic fracturing, the industry has been attempting to establish laboratory testing parameters that assist operators and service companies in their effort to select the optimum proppant for a particular field application. An example of this effort is the development of the “long-term baseline conductivity laboratory test” for proppants. While this test is a huge leap forward in subjecting proppant to simulated downhole conditions, it still does not adequately address many additional factors that can impact the effectiveness of the proppant such as:
a) Proppant fines generation and migration in the fracture
b) Proppant resistance to cyclic stress changes
c) Proppant embedment in the fracture face
d) Proppant flowback and pack rearrangement in the fracture
e) Downhole proppant scaling.
Most proppant choices are currently based on which one has the highest baseline conductivity, along with its cost and availability. While this approach seems logical, it runs the risk of overlooking or under-valuing other critical factors affecting proppant performance in downhole environments.
To better define what constitutes the most effective proppant for a particular application, field cases will be presented that focus on the impact of proppant selection in a number of wells completed in various shale formations. The analysis will examine the production history associated with a variety of proppant choices. In an effort to better understand the production results, a series of lab tests will be performed on the proppants utilized in the field cases. These tests will attempt to establish how these factors (such as proppant fines, cyclic stress, embedment, proppant flowback, and scaling) could be used to explain and support the results of the field cases.