DTD has pioneered the development of a new technology for completing blind wells of extended lengths, even in adverse drilling conditions. The technology retains all the benefits of real-time directional drilling while virtually guaranteeing that well screens and casing can be installed, even in wells several hundred feet long.
Until now, single-ended, or 'blind' well installations required that the bore be completed, then all of the tooling is removed from the bore and the casing installed as a subsequent operation. This method has generally been satisfactory for short wells, up to a few hundred feet, in stable drilling conditions. But when longer wells have been attempted, or if the bore is subject to collapse or caving, the combination of skin friction from casing advancement and caved material in the bore often resulted in failure.
As DTD has completed ever longer double-ended well installations, the need for longer single-ended wells has also been recognized. Through extended research and development, and the building of several prototype systems, the result was a system that retains the ability to navigate and steer, using conventional walkover navigation systems, while allowing the well casing to be placed through the drill string when the bore is completed. By leaving the drill string in place, the bore never has the opportunity to collapse and skin friction during installation is greatly reduced inside the flush-interior drill rods. After the screen and casing are inserted, the drill rods are retracted, leaving the well materials in place.
The method has been extensively tested on several blind wells at an Air Force base in Southern California, where multiple blind wells in excess of 1000 feet in length were installed beneath aircraft runways. The drilling was difficult, but all wells were completed as designed. Without the new technology, it is doubtful any of the wells could have been completed without multiple reaming passes and additional effort.
Several patents have been applied for on this drilling method and the supporting technology. The drilling method is available now for use on sites requiring an innovative way to assure blind well installation. Call Dan or Jason at 800-239-5950 for more details.