A spacer technology said to provide significant time savings for drilling operations has taken a major step forward.

This past June, Sanjel Energy Services was granted patents for its VISWEEP DM (dry mix) IS (invert systems). The spacer system that creates efficiencies through its mix-on-the-fly approach was developed at Sanjel Energy’s technical centre.

“The VISWEEP DM IS spacer system is the next evolution in our spacer family and another excellent example of our commitment to providing our clients with a broad range of innovative solutions,” said Murray Bickley, president and CEO of Sanjel Energy.

Spacer is a fluid that functions as a buffer between well fluids and cement slurry. This helps displace drilling fluid and gets the walls of the wellbore conditioned for cement bonding.

The photos above show the before and after of one of the tests that Sanjel does to test how effectively a spacer system can remove mud. The apparatus is immersed in oil based mud to coat it, then it is immersed in the spacer and turned on for a fixed period of time after which the apparatus is removed from the spacer to determine how effective the spacer was at removing the oil based mud.

The VISWEEP DM IS includes a rapid hydrating polymer mixed, weighting material, and pH modifiers to optimize the mixing process, says the company.

Aimed to improve cement bonding, the system uses powdered chemicals to convert oil-wet casing and formations to water-wet. 

This innovation is a particularly valuable asset for longer, complex wells in the Western Canada Sedimentary Basin, where horizontal sections are common.

While traditional methods have worked for standard vertical wells, when there are horizontal sections, drilling operations face an additional hurdle.

Previously, vertical wells typically reached 3,500 to 4,000 metres. Today, however, wells are commonly 2,500 metres with horizontal sections reaching up to 6,000 metres. This adds to the operation’s hole cleaning and mud displacement workload.

“Batching large spacer volumes may require additional tanks or units, which increases both complexity and the chance of contamination,” says Jeff Spence, Sanjel’s vice-president, operations and innovation, calling it a “labour-intensive process.”

“In the past, if you would hand-mix it, you’d give the operator your recipe, they’d go out to the location, have a series of buckets of and a series of bags of different chemicals and they’d put that all together,” he adds.

At an eight cubic metre volume, VISWEEP DM IS shortens this mixing process from nearly two hours to 15 minutes, says Sanjel.

This system was first used in November 2018 and since then has been used in more than 700 jobs. 

“The technology is really optimized around rapidly achieving properties,” Spence says. “What we wanted to be able to do was mix this on the fly so there are a bunch of efficiency gains for us and for our clients and be able to take a lot of the risk off the table.”

There are some indirect benefits to the environment, as well.

“The energy efficiency aspect of it comes from the amount of time that you’re saving out there,” says Spence. “You don’t have the rig and all the other support equipment sitting around for that 110 minutes of additional mixing time waiting for you to get ready with your spacer to go downhole.”

The emissions savings connected to shopping local supports the case for VISWEEP DM IS, as well.

“A lot of the conventional systems tend to use barite, and barite tends to be sourced out of Asia,” says Spence. “We use, for the most part, a locally-sourced weighting agent that comes out of Alberta.”

Sanjel will clamp down on carbon emissions even further with a new eco-blend line-up of cement.

The company says its new cement has 25 per cent less CO2 output than class G cement, which is standard in the oilfield, and 30 per cent less than the average cement used in Canada.