[Editor's note: A version of this story appears in the August 2020 edition of E&P. It was originally published Aug. 3, 2020. Subscribe to the magazine here.]  

The increased adoption of particulate diverters has led to an accelerated understanding of the performance parameters of this versatile tool. Many advancements have occurred over the last few years regarding their successful application in unconventional fracturing scenarios, and the development of new testing and modeling procedures has led to greater reliability and effectiveness through product specificity around the unconventional space.

DiverterPlus has incorporated tools and manufacturing techniques from a multitude of industries such as computational fluid dynamics (CFD) modeling, ultrafine particle dispersions, and polymer/monomer formulation and finishing processes. This has enabled product development to expand and address new challenges that were either previously unsolvable or high risk when simply using the same particulates used in fracturing operations.

Data application

Turning a large amount of field-collected data on diversion into a functional tool to further the design of stimulation treatments is an ever-evolving effort to leverage hard-earned experience as effectively as possible. The creation of a CFD model that accurately predicts the transport properties of diverter particles has highlighted the inaccuracy of many earlier assumptions about particulate behavior. Through this tool, an understanding of how diverter particles will transport in different fluid viscosities, rates and densities has accelerated the design process and resulted in greater product performance consistency and efficiency.

In another example of the application of data science, the company’s work with the team at StrataGen using FRACPRO.AI is making real-time and post-stage diversion adjustments more effective than ever. The visualization of data trends indicative of success and failure can now be completed almost instantaneously, fully capitalizing on the flexibility of particulate diverters as size, shape, ratio of blends and even polymer formulation can be adjusted in response to what is seen. This has led to a greater degree of refinement in the areas where diverter use is commonplace and substantially shortened the learning curve when solutions to new challenges are being developed.

International applications

Fracturing clients in the Middle East, for example, require more aggressive hydrolysis times in drastically different fluid environments (temperature, pressure, water and hydrocarbon ratios) than what is encountered in the U.S. The formations and proppant used also require substantially different particle sizes to successfully bridge and achieve the appropriate amount of deformation to consistently deliver performance.

Finally, the transit and storage environments required an investigation into specialized coatings and desiccants to ensure product stability and ease of use. DiverterPlus leverages the aid of research partners across the globe to acquire the knowledge necessary for the development of these new products and procedures.

One example of this is the School of Petroleum Technology at Pandit Deendayal Petroleum University (PDPU) in India. By supporting ongoing research at PDPU, the company has been able to take their knowledge and experience with conventional refracturing in the U.S. and learn what applies to the needs of the Indian market.

Additionally, the cooperative development of new testing protocols and procedures are leading to greater levels of understanding of the science of diversion, particularly regarding far-field deposition and proppant interaction. These lessons learned will not only help the company better address challenges in India but will aid in the development of the next generation of products for use around the world.

Microscopy images identify diverter particles with reduced density for suspension in  alcohol- or solvent-based systems. (Source: DiverterPlus)
Offshore application

The needs of the offshore market require a different approach to take advantage of the benefits of particulate diversion. Although the base mechanical properties of standard diversion polymers were sufficient, adjustments to the density, chemical resistance and size of the products had to be made to properly address the needs of the segment. As a result of collaborative efforts with partners with expertise in different industries, the company was able to develop products that are effective in these new applications.

Reduced density particles ensure suspension in alcohol-based systems, while specially coated particles can be used to survive and distribute xylene and other aggressive solvent treatments for an engineered service life before dissolving. Proprietary manufacturing techniques previously used in the printing industry are used to produce particles with specific dimensions and tight size distributions down to the single-digit micron scale. This has expanded the capabilities to produce diverters that can transit an entirely different spectrum of materials (e.g., a gravel pack) and accomplish diversion at a specific point of permeability change (e.g., the formation face).

Another area where particulate diversion technology needed to be refined for the specific environment is in the drillout, cleanout, acidizing, chemical treatment and disposal well sectors. These treatments traditionally utilize lower pumping rates and desire a rapid turnaround, while the pressures the products must withstand are much lower when compared to fracturing applications. This results in the need for a diverter that transports well and agglomerates more aggressively under lower pressure differentials. Traditional fracturing diverters could cause severe issues such as coiled tubing units getting stuck, extended shut-in requirements for diverter hydrolysis and incompatibility with bottomhole equipment and tools.

The chart compares different diverter degradation behaviors of DiverterPlus offerings. (Source: DiverterPlus)

The changes in pressure specifications allowed for the investigation of polymers, compounds and monomers that previously were ignored. This led to the development of several different diverters with drastically different properties than anything previously produced. These new diverters have life spans of several hours instead of several days while having the increased flexibility needed for compatibility with the various deployment methods. 

The resulting diversion blockage is more akin to an extremely high-viscosity crosslinked gel than a plastic plug, but under the lower pressure scenarios, this type of obstruction is an ideal compromise to eliminate costly potential problems associated with premature bridging. These new products bring the benefits of particulate diversion learned from other applications while providing greater operational flexibility than their predecessors.

Effectively distributing treatments of all kinds and managing fluid loss for any desired time interval is now more accessible. New materials, manufacturing techniques and data tools are delivering optimized solutions for new challenges across every segment of the industry with greater frequency.