Dual-Fuel Drilling Advancements: Cat® Dynamic Gas Blending™ Gen 2 Kit Boosts Diesel Displacement

Meeting Modern Drilling Challenges with a Custom Gas Blending Solution

Today’s drilling companies are seeking new ways to reduce costs and lower greenhouse gas (GHG) emissions amid price pressures and shifting industry regulations. Traditional Tier 2 diesel engines incur significant fuel costs, however replacing an entire fleet with new natural gas engines demands substantial capital outlays.

The Cat^® Dynamic Gas Blending™ Gen 2 Kit offers a field-proven method to balance both goals. It’s a next-generation dual-fuel gas blending system that allows drillers to upgrade existing Cat 3512C Tier 2 engines to operate on a diesel-natural gas mix, reducing diesel consumption and GHG emissions.^[1] The kit also supports capital discipline efforts as it allows drillers to upgrade a four-engine rig for roughly the cost of a single new gas engine.^[2]

Leveraging Fuel Flexibility in the Oil Patch

At its core, the DGB Gen 2 Kit is a dual-fuel diesel engine system that dynamically blends natural gas into an engine’s intake, displacing a large portion of diesel fuel with gas. Each engine cylinder is fitted with gas injectors that deliver gas near the intake ports, controlled by an in-cylinder pressure sensing system and an upgraded electronic control. The purpose-built design allows for precise air/gas ratio control on a per-cylinder basis, optimizing combustion in real time. This produces a faster response to load changes and minimal unburned gas compared to other dual-fuel kits.^[3] By injecting fuel directly at the port, the gas blending unit helps promote improved thermal efficiency.

The DGB Gen 2 Kit includes sophisticated in-cylinder pressure sensors that feed data to the engine’s control module. Caterpillar’s engine control system uses this data to fine-tune the gas/diesel blend for each cylinder, ensuring stable combustion across varying loads and fuel qualities. The Smart Engine Management System (EMS) also automatically stops or starts engines on a multi-engine rig to seamlessly match power demand, which boosts operational efficiency and saves fuel.

Engineered to handle a wide range of natural gas sources, the DGB Gen 2 Kit operates on pipeline-quality gas, field gas, compressed (CNG) or liquefied natural gas (LNG) — essentially any methane-rich fuel available on-site. Importantly, it tolerates “hot” field gas with heavier hydrocarbons due to its robust knock detection and control. As the DGB Gen 2 Kit can easily operate with lower methane number fuel, it affords drillers maximum fuel flexibility to reduce diesel fuel consumption and related costs. The gas blending system also provides reliable performance under a wide range of operating conditions.

Diesel Displacement vs. Substitution: The Financial Impact

When evaluating dual-fuel systems, understanding the difference between diesel substitution and diesel displacement is crucial. Diesel substitution is usually defined as the percentage of engine energy input provided by gas instead of diesel, whereas diesel displacement measures the actual volume of diesel fuel replaced by gas.

Substitution figures are less precise, as the amount of diesel replaced is influenced by the energy content of the gas and diesel. Displacement is the most tangible metric for fuel savings as it directly reflects how many gallons of diesel are saved when operating a dual-fuel engine.

The DGB Gen 2 Kit’s high diesel displacement rate delivers significant fuel cost savings and a field-proven return on investment. By achieving an average 70% diesel displacement and up to 85% peak displacement,^[4] drilling companies can save tens of thousands of dollars in fuel per rig each month.^[5]

Leading driller H&P’s Eagle Ford operation demonstrates the benefits of leveraging advanced dual-fuel technology. To reduce diesel consumption costs and promote greater use of natural gas for their customers, the company retrofitted selected rig engines with the Cat DGB Gen 2 Kit. Over a nine-month period, the DGB Gen 2 Kit enabled H&P to achieve an average diesel displacement rate of 75% and save more than 94,000 gallons of diesel on a single rig with more than 4,500 engine hours.^[6] At current diesel prices,^[7] that equates to hundreds of thousands of dollars in fuel savings alone. Upgrading H&P’s existing rig engines with the DGB Gen 2 Kit during overhaul ultimately saved the company millions by reducing capital and operational costs while also lowering diesel consumption to support its GHG emissions-reduction goals.^[8] Based on the positive results experienced to date, H&P plans to upgrade over 60 rig engines this year.

Fueling the Future of Drilling

The Cat DGB Gen 2 Kit exemplifies the innovative, practical solutions today’s drillers require. It simultaneously lowers fuel spend, reduces GHG emissions and improves asset utilization with a single upgrade package. The kit also helps lower total cost of ownership while providing the power and responsiveness drillers demand.

Fuel flexibility provides important advantages in the field. Dual-fuel technology empowers drilling companies to adjust fuel mixes based on gas availability and to continue operating if gas supplies are interrupted.

By combining high diesel displacement rates with reliable performance, drillers can accomplish more with less diesel — an outcome that resonates strongly with today’s oilfield companies. Backed by an extensive dealer network offering 24/7 support worldwide, the DGB Gen 2 Kit’s ability to reduce costs, support sustainability-related goals and extend asset life makes it an essential technology for modern drilling rigs.

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