How many trucks and trailers does a CNG delivery network need?

A fleet is capital. Too few trailers and a rig runs dry, switches back to diesel, and the service promise breaks. Too many and the money sits parked in a field the operator may leave within a year.

The timing raised the stakes. In 2013 North Dakota flared more than 30% of the gas it produced. In 2014 the state adopted capture targets that stepped up toward 90% by 2020, and operators needed somewhere for that gas to go. Ferus and GE built the answer as a joint venture called Last Mile: GE's CNG In A Box compression next to the wellhead, Ferus trailers and logistics on the road. Statoil ran the first pilot near Watford City, then expanded it in 2014 to six drilling rigs and a frac fleet.

Moving from pilot to commercial scale is the moment a fleet gets bought. Ferus wanted the number before signing the orders, and it wanted the number to hold on the worst day of February, with the lowest cost that still delivered 100% service.

Nothing in the network stays put. A route plan assumes fixed customers; here both supply and demand migrate with drilling activity, so the geography of next quarter is unknown today.

Travel times swing with weather. Trailers tied up as on-site storage are trailers not hauling. A tractor in the shop is a tractor not dispatched. Averaging each of these in a spreadsheet looks reasonable and hides the day that matters: a storm doubles drive times while two rigs run low at once and a tractor is down for maintenance. Service fails on that day, and a fleet sized on averages never sees it coming.

SimWell built a discrete-event simulation of the distribution system in Arena. Because future well locations cannot be known, the model places supply points and customers on a latitude and longitude grid laid over the road map of the service area. A travel calculation tool returns drive times between any two grid points. A Markov chain moves the system between weather states and stretches travel times accordingly. A dispatch algorithm written for the model assigns tractors and trailers to deliveries the way the operation would, including the trailers left on customer sites as storage.

With the operation running in the model, Ferus could change the fleet and watch the service level. Scenarios covered tractor count, trailer count, and the operating processes for dispatching and swapping trailers.

Ferus sized its tractor fleet and its trailer fleet from the model, with weather, maintenance, and road closures in the run rather than averaged out of it. The same model let the team test its operating processes side by side and choose the most efficient one.

Ferus went into the Bakken winter with the fleet the service promise required, at the lowest cost that promise allowed, and nothing bought on a margin of comfort.

Ferus sized its tractor fleet and its trailer fleet from the model and chose its operating process from the alternatives it tested, holding the 100% level of service it had promised while keeping fleet capital at the minimum that promise allowed.

The industry outcome the network served has held. North Dakota's gas capture rate ran at 94 to 95% through 2025 and into 2026, above the state's 91% target. In February 2024 Ferus Natural Gas Fuels merged with Cryopeak LNG Solutions to form Cryopeak Energy Solutions, the largest private, vertically integrated LNG producer and service provider in Canada.