Drilling operations have come a long way in improving both crew safety and protecting the environment. Operating companies recognize the benefits of providing a safer working environment and minimizing their impact on the land. In many cases, however, safety and environmental performance hits a ceiling without a fundamental change in the “fit, form, or function” of the traditional rotary drilling operation.

The heart of the RSS is the 27-lb Kelly Kan, which is basically a plastic mud bucket with a replaceable seal that can be sized for pipe between 2 in. and 8 in. in diameter. (Images courtesy of Katch Kan USA, LLC)

Working together

The Environmentally Friendly Drilling Systems Program (EFD), co-funded by the Research Partnership to Secure Energy for America (RPSEA), industry, and environmental organizations, works to integrate advanced technologies into systems that significantly reduce the impact of petroleum drilling and production in environmentally sensitive areas.

The team focuses on technologies for environmentally sensitive development of unconventional energy sources that can help maintain the present standard of living and preserve quality of life. The objective is to identify, develop, and transfer critical, cost-effective new technologies that can provide policy makers and industry with the ability to develop US domestic reserves in a safe and environmentally friendly manner.

One member of the EFD team, Katch Kan Ltd., has developed an innovative rig- and worker-friendly technology that reduces repetitive injuries and minimizes the impact of drilling operations. The Katch Kan Rig Safety (RSS) and Zero Spill System can be installed on any rig in any working environment. It attaches to any rig without tools and requires no structural modifications to the rig. The systems protect the worker and the environment by completely containing drilling fluids released in and around the rig floor when making and breaking pipe connections.

Today’s challenges

The most active drilling plays today usually require horizontal wells to maximize the productivity of tight reservoir or shale rocks. Drilling engineers find it beneficial to drill at or near balance, which can increase the amount of fluid that escapes from pipe connection operations while both drilling and tripping. Horizontal drilling techniques like back-reaming and multiple-hole cleaning trips tend to amplify the problem.

Fluids caught in the upper Katch Kan are returned to the fluid system via the return line, reducing drilling fluid waste and spillage.

Some companies have reported average surface losses of drilling fluid on a typical Woodford, Fayetteville, or Haynesville horizontal well of more than 200 bbl. If problems occur that require additional bit trips or if well flows occur, the amount of drilling fluid lost on the surface can be well over 1,000 bbl.

The cost of lost drilling fluid can be high, exceeding tens of thousands of dollars per well. Cost aside, when fluid releases occur, they generally end up going directly onto the ground, which nearly always necessitates costly remediation once drilling has concluded.

Environmentally, the impact is greatest when using hazardous materials such as invert or oil-based fluids. Not only are workers exposed to releases on the rig floor, but the entire site is exposed to fluid. Surface contamination can be significant, requiring investment after the fact to restore the site to its original state and ensure groundwater contamination is averted.

A better approach

Much potential contamination is avoidable. Using the zero-spill system in conjunction with the RSS captures fluid releases and returns them to the rig fluid system for recycling or reuse. The net result is a minimally impacted well site, a less expensive operation, and a rig that is cleaner, safer, and more efficient.

The system is an off-the-shelf, self-contained service that is meant to work in an integrated fashion to contain, redirect, recycle, and reuse drilling fluid escaping from the making and breaking connection process for both drilling and tripping. All components are made from a light, strong “super-polymer” that is temperature- and invert-resistant. These characteristics make the products suitable for oilfield use in extreme temperatures and on drilling rigs using any type of fluid, including oil-based or invert fluids that are prevalent on horizontal wells.

Protecting the rig floor

Any spill containment system on a standard drilling rig has to protect the rig floor. The RSS combines several key technologies to address spill containment. The heart of the RSS is the 27-lb Kelly Kan, which is basically a plastic mud bucket. Its light weight makes it easy to handle and requires no heavy lifting devices. The bucket has a replaceable seal that can be sized for pipe between 2 in. and 8 in. in diameter, making it useful on drillpipe, collars, and casing.

The second component of the RSS on the rig floor is the splash guard, a flexible ring that fits around the rotary table and stops the drilling fluid (which is directed downward from the Kelly Kan) from splashing and spreading onto the drill floor. The splash guard also acts as a safety barrier to the rotary table while drilling and can keep ropes, slings, chains, etc., from getting caught in the rotary table or Kelly bushing.

Once fluids have been contained and redirected through the rotary table, the zero-spill system can catch and save fluid. The system comprises three main components — the upper Katch Kan, lower Katch Kan, and adjustable containment enclosure.

The upper component works in conjunction with an integrated flow nipple that is equipped with a wear ring and flange/seal system. The flow nipple is dressed with a junk basket that is welded in place; the Upper Katch Kan is connected to the junk basket flange/seal system to form a fluid barrier. Fluids released from the Kelly Kan on the rig floor are directed down through the rotary table and are caught in the upper Katch Kan.

Fluids caught in the upper Katch Kan are returned to the fluid system via the return line, reducing drilling fluid waste and spillage. In some instances, the amount of fluid being redirected downward by the Kelly Kan is significant, especially when drilling under-balanced, and the upper Katch Kan is not sufficient to completely contain the redirected fluid; in this case the lower Katch Kan must be used.

It is also common on horizontal wells for operators to specify the use of a rotating control device (RCD). The primary function of the RCD is to provide pressure control. Although the RCD is a recognized means of containing drilling fluid while the pipe is rotating in the hole, it can leak. In these instances, it is not uncommon for the substructure area of the rig to be covered in drilling fluid, which requires either constant attention by valuable rig personnel or significant cleanup once the well is completed.

Using the Katch Kan and adjustable containment enclosure can contain the spray of drilling fluid caused by the RCD. Most importantly, they can catch the fluid being redirected down through the rotary table by the Kelly Kan. The lower Katch Kan is equipped with two 4-in. drain boxes from which a hose and pipe system can take the fluid back to any of several locations, including the cellar, trip tank, or outboard containment system.

The preferred method is to send the captured fluid back to the trip tank for complete reuse in the fluid system, a method that provides the largest savings when large amounts of drilling fluids are contained.