In northwest Russia, about 120 km north of the Arkhangelsk region in the Verkhotina license area, an Atlas Copco T3W water well rig is hard at work. When traveling to the mine through rigid, demanding terrain (often covered in multiple inches of snow dependent upon the time of year) it’s evident that you’re traveling to one of the more remote areas in the world. With nothing but road and forest in the surroundings along the way, the first sign of life is upon arrival at the mine camp some three hours later after departing Arkhangelsk City.
The Grib Mine diamond deposit was first discovered back in 1996. Once discovered, the race was on to win majority ownership of the diamond pipe that lies in northwest Russia. After 12 years of lawsuits and controversy, the winner was the chief executive and controlling shareholder of one of the largest private oil and gas companies in the world; Lukoil.
After purchasing the diamond deposit in April of 2008, the project at the Grib Mine was underway just a little less than three years later in January of 2011. However, in order to effectively extract the diamonds from the deposit a large amount of water would have to be removed.
Arkhangelskgeolrazvedka (AGR) is a Lukoil sister company and was contracted to dewater the Grib Mine. After drafting a mine plan it became evident that dewatering holes were going to be essential if the mine was going to be productive over its 15-year life span. AGR began researching which machine they would need to add to their fleet of one water well drill, which is currently a 15-year old Russian model.
General Director of AGR Igor Prokudin said his mind was made up when he visited an Atlas Copco T3W in the eastern region of Russia. “We visited a drill rig in Kuzbass and we loved it, and it was exactly what we wanted to get,” said Prokudin through a translator. Prokudin discussed the prospect of acquiring a T3W water well rig for a little more than two years with Atlas Copco salesman Alexander Shpekht helping him through the process. Prokudin liked that there are multiple Atlas Copco branches in the region and all throughout Russia, and said Atlas Copco’s presence in the area made the decision to purchase a T3W that much easier.
Shpekht, who was awarded by Atlas Copco Drilling Solutions for his outstanding excellence in deephole sales in 2011, is the one who took Prokudin to Siberia to show him how the rig works in some of the world’s toughest conditions. Shpekht also worked with AGR to calculate different technology parameters for the rig to show Prokudin and AGR how it would work in a variety of geological conditions. When it became clear that the geological conditions were more difficult in reality than they had originally estimated on paper, it made the idea of working with Atlas Copco more attractive after Shpekht helped AGR through the process.
The biggest obstacle for AGR in purchasing the Atlas Copco T3W was making sure they had the job with Lukoil. Once they signed the contract with Lukoil to drill dewatering holes around the mine, AGR purchased the T3W water well rig for the project.
AGR began drilling with the T3W in July of 2011 and plan to drill a minimum of 40 holes around the mine for dewatering purposes. There are also a few monitory wells, which are often used to sample groundwater for chemical substances that will be used for exploratory purposes. AGR uses its Russian model water well rig for exploratory well drilling around the mine.
Efficiency is one, if not the largest benefit for AGR regarding their T3W water well rig. According to one drill operator, the speed at which they can drill a single hole is four times faster than when they’re using a Russian model rig. Currently, AGR is using the T3W to drill holes approximately 100-to-300 meters in depth with a hole diameter starting at 650 mm, and the hole is completed at 381 mm depending on the depth drilled. The depth of each hole depends on the water bearing zone location, because as much water as possible needs to be pumped from the hole and to do that the water bearing zone must first be crossed.
For now, they’ve drilled only three holes because they’re still testing different technologies and learning how to manage the geological conditions they’re faced with. Although it’s difficult to determine now, Prokudin says, “It’s most important for us to choose the right drilling technology.” Currently AGR is searching for the right combination of drill bit and flushing medium with a goal of using a down-the-hole drilling method using air to drill to depths of approximately 100 feet (30 meters), with clay serving as the primary drilling application.
There’s also the possibility of using foam or mud drilling to complete the rest of the hole, which will be drilled to depths between 820-885 feet (250-270 meters). To drill the hole, AGR is using an Atlas Copco QL120 DTH hammer along with a 381 mm bit that’s also supplied by Atlas Copco. The spherical bit is designed to drill in medium rock abrasiveness and can create a hole up to 110 mm in diameter.
There is also an Atlas Copco XAHS 186 compressor that is used for developing the water well after the T3W finishes drilling the hole. The compressor is needed to pump out the cuttings from the hole and remove small fragments of sand that can wear the pump out in a matter of hours. The compressor is instrumental in the well’s development, because it moves as much excess mud and water from the hole’s wall in order to make the water bearing zone as productive as possible. This process can take between three and seven days depending on how fast it takes clear water to emerge from the hole. Once clear water appears, a small pipe that was needed to inject air into the hole is removed, and a submersible pump is placed in the hole to pump the water on a regular basis by an electric motor. The water bearing zone is not at a defined depth around the mine, and needs to be crossed in order to remove as much water as possible from the depth that the hole needs to be drilled in that particular location.
One of the more noticeable adjustments AGR has made to the rig is the side paneling they’ve built to keep the machine warm and protect it from the many elements it battles on a daily basis, especially during the winter months (December-February). Needless to say, AGR purchased the cold weather package for their T3W, as the average temperature in the Arkhangelsk region during the winter ranges on average from 14 to 20 degrees Fahrenheit in the beginning of winter down to -30 degrees Fahrenheit (-40 degrees Celsius) as the winter season grows old. Once winter has passed, the crew will remove the side paneling on the rig for the spring and summer seasons.
As production at the Grib mine goes on, pumping out excess mud and water will prove vital for the mine’s productivity. Currently, AGR couldn’t be happier with how their T3W is drilling, and as time goes on productivity is likely to increase once the driller’s become more comfortable operating the rig and learning what type of drill bit and flushing medium works best in the demanding conditions offered in northwest Russia.