Blind Technique For Horizontal Wells

Let’s separate the truths from the myths as they apply to the drilling and installation of horizontal remediation well through the blind technique. But first, what is a blind installation? It is often assumed that the installation of horizontal remediation wells requires both an entry point and an exit point; an entry point for the insertion of the drill pipe and an exit point where the drill pipe exits the subsurface and the well material is pulled back into place. The process of blind installations, however, is a process that eliminates the need for an exit point. Instead, the well bore is terminated in the subsurface at the far end of the proposed screen and the well material is pushed into place. As a result, more screen can be placed in direct contact with the contamination, while access restraints that prevent vertical wells and entry-exit installations are avoided. The successful installation of horizontal wells through blind techniques relies on the method and mud. Horizontal directional drilling is exclusively a mud-rotary operation. Unlike vertical well installations, gravity constantly works against the integrity of the horizontal borehole. The mud is required to stabilize the borehole, preventing collapse so that the well materials can be installed safely and effectively.

 

Mud and Additives

The successful installation of blind horizontal wells is more than a “choice” between biopolymers and bentonite, it requires a site-specific development of a horizontal drilling mud, or “fluid,” program. Without the correct mud, there is a greater threat of borehole collapse, recirculation failure, and improper well installation. Mud programs can be composed of a bentonite base or a biopolymer base, both of which are appropriate for different site conditions. The myth revolving around biopolymer-based muds is that they lead to better communication between the well and the surrounding formation. The truth is that if a well is developed properly, there should not be any mud left in the borehole, whether using a bentonite or a biopolymer base. Both options are supplemented with additives during the development process to help break down residual mud in the borehole. Biopolymer options, however, are significantly more expensive to purchase and produce more drilling waste as the fluid is more prone to react with clay content in the surrounding formation. DTI has experience in mud science for geologic conditions all over the country and is always able to help develop the right program for your site, whether bentonite or biopolymer-based.

Restrictions on Distance?

It may seem that blind wells have restrictions on how far they can be drilled and installed. So how much footage can we actually get in the ground without an exit point? While entry-exit techniques are often better suited for longer and larger-diameter installations, blind wells can be installed to distances of 1,000 feet or more with the correct technique and site-specific, curated mud program. DTI has pioneered many of the blind horizontal well installation techniques used today in various site conditions around the globe, working with access constraints instead of against them to knock out contamination. How can the advantages offered by decades of technological advancement in the field of horizontal wells benefit your project?  Call our horizontal remediation well experts at 1-877-788-4479 to discuss your current project needs or email us at drilling@directionaltech.com with questions, review case studies, and learn more. Written by: Elliott Andelman, Professional Geologist