New Technology Saves 7 Days In Drilling Time

NDIC says it takes about 20 days to reach total depth.  It looks like about five days to reach vertical depth and fifteen days to reach  total depth from there. I don't read many well files, but of those I read, it doesn't seem like all that many wells are reaching TD in 20 days. I still use 30 days as a general rule of thumb. (The guys and gals in the field are probably laughing.)

A reader sent this story; it's very technical but worth reading even by a layman. High points:

• international conference; held in Amsterdam
• Forbes 500 oil services company: Weatherford
• Bakken used as a laboratory (again)
• new steering technology
• compared two wells

• well #2: horizontal rate with old technology: 31 feet/hour
• well #1: horizontal rate with new technology: 38 feet/hour

• well #2: length of lateral using old technology: 8,956 feet (failed to meed planned TD)
• well #1: length of lateral using new technology: 10,217 feet

• well #2: 8,956/30.67 = 292 hours of actual drilling with old technology
• well #1: 10,217/38.08 = 268 hours of actual drilling with new technology

Conclusion of the article:

As a result of the smoother wellbore, the operator had a trouble-free casing run in Well #1. The system consistently achieved more than 93% rotation in the lateral in both wells. This was a significant improvement from previous wells, which achieved roughly 70% rotation. On the first well, sliding time was reduced from 30% to 8%, saving seven days of rig time and the associated drilling costs.

As drilling progressed, these wells required frequent directional updates, due to formation faults. Consequently, this required many target changes for geosteering. ROPs in the first Bakken well were higher than the second well, since more time was spent sliding to correct the well path on #2 without TBS technology. Use of TBS technology on Well #1 enabled the operator to have precise steering control and drill a smoother wellbore. The second well reached TD early, due to an inability to overcome high frictional forces in the lateral leg.

From the linked article, this is the technology:

To improve performance in these [Bakken] laterals, operators have been looking for a while now, for an economic alternative to rotary steerable systems (RSS’s), while still retaining their basic benefits.

Lead author Wendell Bassarath said that a new system to achieve 3D directional control was developed to improve drilling efficiency, using targeted bit speed (TBS) technology. The system uses a conventional positive displacement motor with a bent housing and an MWD tool that mimics many of the features offered by an RSS. The steering technique was achieved by accurately modulating the flow of the drilling fluid through the drillstring.

This allowed rapid variations in the drilling parameters to accurately control the bit speed along the desired toolface setting. If wellbore objectives could not be achieved in rotary mode using TBS technology, then the mud motor could be oriented in a conventional manner to follow the well plan.