Traditional blind well installation requires drilling along the designated bore path to the end of the proposed screened interval, and then removing all of the drill tooling prior to installing the well materials. This leaves the bore open (supported with drilling mud) for the brief intervening period between drilling and placement of the well materials. This traditional technique works fine for short wells or where ground conditions are cohesive enough to allow the borehole to stand open without caving. However, in coarser non-cohesive soils or longer wells, there is a significant chance of collapse of some portion of the bore, and therefore, the inability to place fully into the bore and into the designed position. A well screen that is set short of its target can lead to ineffective treatment at best, or an unusable well at worst.
DTD has developed a patent-pending, cost effective way to case long boreholes in order to stabilize the formation and allow the installation of well screen and casing. At present the technique allows the setting of 3-inch or 4-inch blind wells confidently to lengths well over 1,000 feet.
With forthcoming approvals we will publish additional information from the project in which this approach was used. For further information on blind well installation contact: [email protected]