Ronald G. Dusterhoft

New Guidelines for Applying Curable Resin-Coated Proppants

Both curable-resin precoated proppants (CRCPs) and on-site liquid-resin-coating (LRC) systems are used in hydraulic-fracturing treatments to reduce proppant flowback after fracture-stimulation treatments.

Controlled Viscosity Reduction and Increased Fracture Conductivity Using a High-Temperature Breaker System

High-temperature fracturing-fluid breaker systems have been used in fracturing operations for the past several years. The advantage of using these systems has been improved fracture conductivity, but there has been an increased risk of poor proppant placement and premature screenouts resulting from early viscosity reductions as the fluid is exposed to high temperatures. In many cases, this problem could only be avoided by adding breaker to the final portion of the proppant stages, essentially improving the fracture conductivity in the near-wellbore region without enhancing the conductivity of most of the proppant pack. This paper highlights innovative research for developing high-temperature breakers that work synergistically with gel stabilizers to maintain excellent gel viscosity. This viscosity allows sufficient time to place the treatment while still providing a more complete break and improved fracture conductivity. Laboratory testing has shown that this high-temperature breaker system can be used effectively at temperatures as high as 350°F without sacrificing early-time fluid viscosity or proppant placement, while still providing dramatic improvements in fracture conductivity. Field production has been analyzed and shows the combined benefits of improved proppant placement and increased fracture conductivities obtained with the application of this technology.

Shale Reservoir-Centric Completions

In North America, the transition from more conventional reservoirs into tight, basin-centered gas and now source shales has caused the industry to change the way reservoir performance is being assessed, measured, and documented. Historically in conventional reservoirs the reservoir quality was carefully examined on a well by well basis to determine reserves in place and exploitation plans. For unconventional reservoirs, however, the commercializing of such plays quickly became centered on horizontal drilling of long laterals combined with massive volume, high rate multi-stage hydraulic fracturing. In that environment, completion design and hydraulic fracturing have become more of a statistical process; additionally, incremental improvement and innovation are used to create a treatment schedule often replicated across an entire field without consideration of reservoir variability across a lateral. Based upon vertical well experience, the fracture initiation points can be carefully selected by identifying the locations within the well that are best to perforate. In a horizontal well, however, the location of the lateral defines the fracture initiation points anywhere along the well, so the stratigraphic location of the well lateral becomes critical in non-homogeneous shale plays. To address this, engineers and geoscientists can identify important parameters necessary for optimum completion design, and earth modelling can then be used as a tool to capture and model these properties across the asset making critical information available as needed for drilling, completion, and production operations.