WorldWide Drilling Resource

Maximize Drilling Efficiency with HERCUL-EZ ™ Adapted from Information by CETCO ® HERCUL-Ez ™ is a cutting-edge additive used in conjuction with bentonite-based drilling muds for horizontal directional drilling. With proper formulation, the system will produce a unique drilling fluid with excellent shear thinning characteristics. At low shear or at rest, the fluid will gel and allow for suspension of large cuttings, yet it will thin immediately under pumping conditions. At rest, HERCUL-Ez fluid looks and behaves like a semifluid, but when sheared, it will revert back to a thin, almost water-like consistency. HERCULE-Ez is designed to be compatible with CETCO ® bentonite drilling fluid. For mixing and application purposes, pretreat freshwater to achieve a pH of ten or higher. Bentonite should be added and allowed to hydrate for at least 20 minutes before adding HERCUL-Ez. Once HERCUL-Ez is added, it should be mixed for 5-20 minutes before pumping. It is important to allow adequate prehydration of the bentonite to maximize performance of the system. Anionic additives such as polyanionic cellulose (PAC), partially-hydrolyzed polyacrylamide (PHPA), and thinner should NOT be used with the product. HERCUL-Ez is ideal for difficult-to-drill applications such as large river crossings or in gravel and cobble. When drilling in these difficult places, its unique filter cake means fluid is contained in the borehole. The extreme shear thinning nature of HERCUL-Ez is well suited for mud recycling systems, as well as situations where excessive flow rates are present and pump pressures are to be avoided. It also helps prevent formation bridging and blockage due to settling of drill cuttings. Its flow pro- file is plug-like for more complete borehole sweeping, and thinning only occurs at the borehole walls and drill stem. Rejuvenating Good Wells Gone Bad Adapted from Information by AmeriWest Water Services Inc. Why do good wells go bad? Many factors can contribute to decreased water yields. Some of the more common factors which can cause well production to drop off over time are blockages of well casings, well screens, and the adjacent water-bearing formations. Regardless of the particular factor, the bottom line is increased movement of water toward a well causes blockages. These blockages or incrustations will be found in the form of biological plumbing, chemical/mineral incrustation, or mechanical/physical plumbing. A good preventative maintenance program can help reduce or possibly eliminate the need altogether for rehabilitation, but sometimes a well rehabilitation is needed. In either case, when done correctly, the benefits could far outweigh the costs. One such example is a well constructed in Boise, Idaho, in 1978. The well was converted to an aquifer storage and recovery well (ASR) after 21 years, due to increasing manganese levels. Prior to beginning ASR, a well rehabilitation was performed in 1988, which consisted of mechanical swabbing without chemical additives. The specific capacity of the well was increased from around 11 gallons per minute per foot (gpm/ft) to about 18 gpm/ft with a maximum flow of 1400 gallons per minute. However, operating as an ASR well made it prone to plugging, so the pump capacity was downsized from 1000 gpm to 600 in 1999. In the five years after the pump capacity was downsized, three more attempts were made to improve the well’s efficiency, but none of the maintenence brought productivity up to pre-ASR levels. Furthermore, there seemed to be a limit to the specific capacity of about 10 gpm/ft of drawdown. The well continued its downward trend of significant losses in capacity, which prompted another rehabilitation effort in 2006. This time, AmeriWest Water Services Inc. provided KlearWel l Acid Base, KlearWell 186 BioMin Dispersant, and KlearWell NIS Surfactant as part of the rehabilitation process. The result was a 264% increase in specific capacity from 8.1 gpm/ft to 29 gpm/ft. Additionally, pumping capacity jumped 95% from a low of 550 gpm to an average of 1075 gpm for over a year and a half. The sav- ings in energy costs, combined with increased earnings from water sold, produced a return of the cleaning cost investment in just three weeks. The change in the well’s pumping rate pro- vided the water company additional rev- enue of approximately $1200 per day. A good well gone bad might look like a half-empty glass for a time, but with the right cleaning or rehabilitation, the glass could be filled to the brim. 26 JANUARY 2018 WorldWide Drilling Resource ®