Key Factors Affecting Well Performance

Water Law Resource
July 1, 2013 — 4,202 views  
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Developing a high performing well has long been a concern of contractors, and now that efficiency has gone mainstream among consumers, it's more important than ever. From drilling processes to the finishing touches and finer details, there are a number of key factors affecting well performance that contractors should get to know.

Drilling Methods Have a Direct Impact on Well Efficiency and the Speed of Installation

Like virtually all contacting jobs and professions, well drilling has evolved over time and has come to encompass multiple drilling methods that meet different demands and use different equipment. Each of these methods works for different reasons, and each method will have a different impact on the performance of a new well. 

Percussion Drilling

The percussion drilling process actually uses a bit to "hammer" or "drum" the ground, slowly creating a well by hammering out pieces of earth strata that lie between the surface and the aquifer. While this is the oldest and most affordable method, it presents some efficiency challenges. Well lining must be installed as the percussion drilling proceeds, allowing for now performance-minded adjustments after completion. It also is the slowest of the drilling procedures and the one most likely to damage the land surrounding the new well.

Direct Rotary

Developed as a logical evolution of percussion drilling, the direct rotary process is one that solves many of the most common problems associated with the percussive process. The biggest advantage is that the rotary method actually allows for an evaluation and adjustment of the well hole before it is lined and made into a permanent fixture. This allows for the assessment of inefficiencies and the correction of any problems that might severely limit the performance of the well.

Rotary drilling itself is highly efficient, and the wells it creates are likely to be more efficient as well. Perhaps the only drawback of this method is a strict, 22-inch limitation on the size of the well hole.

Reverse Rotary Drilling

The reverse rotary drilling process trades Bentonite drilling fluid for water and, instead of placing drilling fluid around the outside of the bit, it is carried up through the center of the hardware. That allows for even less compaction than regular rotary drilling, creating a well that is both more efficient and more durable in the long-term.

Reverse rotary drilling also allows for the creation of wells larger than 22 inches in diameter, making it a great option for commercial and agricultural wells that serve larger purposes. This type of drilling generally creates smoother, larger, and higher-performing wells than either of the other two options.

Engineering Concerns: From Screens to Gravel Pack and Special Finishing Processes

As is the case with virtually any technology or construction project, it is often the finer details that can make or break the efficiency of a new well. From well screens to gravel pack, contractors have a number of finishing tools at their disposal to ensure increased well performance.

Well Screens

The use of well screens is a relatively recent development, but one that is very important for long-term well performance. These screens are placed at the bottom of the well opening, protecting the water from being contaminated with sand and silt. This increases the efficiency of the well's pumping equipment, as excess sand and silt can clog moving parts and lead to a great deal of energy drain. With a variety of screen types and materials, there's one for virtually every type of well or landscape.

Gravel Pack Procedures

Gravel pack supplements a well screen by acting as a natural filter between the well's walls and the earth strata that surround it. A tight gravel pack can actually filter out sand and silt without manmade materials, acting as a one-two punch complimentary to screen installation.

The Well Development Process

Well development allows engineers to compensate for any damage done to the ground in the area where the well was installed. Using gravel pack and other techniques, they can undo the damage done to certain layers of the earth that might later collapse or present problems to the well's efficiency. This allows the well to perform better for a longer period of time, and it reduces the likelihood of time-consuming maintenance years after completion.

Attention to Detail Creates Better Wells

From gravel pack to choosing the right kind of drilling process for each well, contractors should get to know the finer details of the well's function and environment, and then create a plan of action that compensates for those unique characteristics. By planning for the future and compensating for unique engineering issues, wells can be designed to perform well for decades to come.

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