Replies to This Discussion

Permalink Reply by Keith A Williams on June 9, 2013 at 4:59pm

The Hiker,

I went to Wiki and got this:

Drilling to targets far laterally from the surface location requires careful planning and design. The current record holders manage wells over 10 km (6.2 mi) away from the surface location at a true vertical depth (TVD) of only 1,600–2,600 m (5,200–8,500 ft).^[4]

Link to Wiki

HTH

Keith

• ▶ Reply

Permalink Reply by The Hiker on June 10, 2013 at 12:44am

Keith:  Thanks, and Wow.   So, although preferable, the pad really doesn't have to be close to the lateral location.   Conceivably, a landowner with a pad might assume they are automatically in the unit.  Not so, the unit might be a mile away.  That would be something to know before a landowner automatically agreed to the construction of a pad!

• ▶ Reply

Permalink Reply by Brian Powers on June 10, 2013 at 8:22am

T. Hiker-

All horizontal wells start vertical at surface, angle gets built from 0° to 90° before the start of the lateral. Depending upon the pad configuration and mobility of the rig substructure, the surface locations can be quite close to each other; offshore the surface slots are typically about 10 feet center to center.

The contractor designing the directional drilling part of the well will generate a directional drilling profile that takes into consideration all adjacent well profiles. One of the last things an operator wants to do is to drill into adjacent wells- very bad things may happen.

 

I haven't seen too many well sketches from these wells, but I surmise that two strings of cemented steel casing are used, one to cover and protect near surface groundwater, and an intermediate string above the lateral. Steel liners with frac sleeves are often run into the lateral section after it is drilled and logged.

To me, the deviation angle does not matter as much as the smoothness of the profile. Again, the directional drillers will design a profile to a maximum "dog-leg severity" (DLS), typically 2-3° per 100 ft of hole; specialized runs are sometimes made before running casing to condition the mud and ream out any ledges or tight spotsin the borehole before running casing or liner. The well operator management teams frown when casing or liners get hung up and have to be pulled and re-run after conditioning the hole again. This is a good way to "throw good money after bad money" very quickly.

 

I see your scenario as being feasible, subsurface considerations notwithstanding, but the operator may not like building a second well pad unless the target is prolific wet gas.

 

Brian 

• ▶ Reply

Permalink Reply by The Hiker on June 10, 2013 at 9:48am

Brian:   Thanks for the answer.  I'm trying to understand how an operator would fully develop the acreage underneath a lake, if pads could only be built around the perimeter.   Excellent wet gas potential.

• ▶ Reply

Permalink Reply by Brian Powers on June 10, 2013 at 1:09pm

TH-

Drilling under lakes and other water features is common practice. Back in the early '80's, Amoco Production company drilled a number of wells under the Great Salt Lake in Utah. The caps and T-shirts all said "Offshore Utah Drilling Team." They were all dry holes in my recollection.

 

Good luck!

 

Brian

• ▶ Reply