Comparative Advantages
Taking a look at surging and airlift pumping in well development.
By Thom Hanna, PG
Developing a water well is a critical phase in the completion of any groundwater extraction system.
Figure 1. Comparison of surging and airlift development showing that airlifting only pulls water into the well while surging agitates the formation and filter pack with bidirectional energy.
The goal of well development is to enhance the hydraulic efficiency of the well by removing fine sediments and drilling debris from the formation around the well screen, thereby increasing specific capacity and reducing turbidity, drawdown, and long-term maintenance needs.
We’ve covered development previously in this column, but I often get the question of the differences between surging and airlifting. So, let’s take a look at the two methods here.
Two of the commonly used methods for development are airlift pumping and mechanical surging (Figure 1). Airlift pumping is popular for its simplicity and effectiveness in removing loose debris. In smaller domestic wells drilled using air rotary and shorter screen lengths, airlifting generally provides good development. However, in wells with longer screen intervals typical of high-capacity wells, airlifting alone is generally not effective.
Figure 2. Effective development requires movement of fluid in both directions through screen openings (right side). Movement in only one direction (left side) does not produce the proper development effect (Sterrett 2007).
Surging, however, provides a more dynamic approach, directly targeting the formation interface to mobilize and remove finer particles that are otherwise difficult to extract (Sterling and Helweg 1990). This column explores the technical distinctions between these methods and presents advantages of surging, particularly when used in combination with airlift pumping, as demonstrated in both field studies and
engineering literature.
To better understand the mechanical differences between surging and airlift pumping, Figure 1 shows:
- On the left, the reciprocating motion of the surge block creates inflow and outflow across the screen.
- On the right, the upward-only flow of airlift pumping, which clears debris but does not effectively disturb the zone outside the screen.
The bidirectional flow of surging is the key advantage that enables it to target and clean areas that airlift pumping may bypass (Figure 2), leaving bridges in the filter pack that can result in sand pumping.
Understanding Airlift Pumping and Its Limitations
Airlift pumping works by injecting compressed air into the water column within a well casing. The air reduces the density of the water, creating an upward flow that lifts water and suspended materials out of the well (Figure 3). This method is especially useful in removing water and mobilized fines that have already entered the borehole or screen.
However, a significant limitation of airlift pumping is its inability to disturb or mobilize fine particles that are still lodged in the surrounding formation or within the filter pack. Like other continuous pumping methods, it tends to preferentially draw water from zones that are already open or hydraulically conductive. As a result, clogged, compacted, or bridged zones may remain untouched, which compromises the efficiency and longevity of the well.
In formations with high clay or silt content, or where particle bridging has occurred, airlift pumping may clear only a small portion of the screen’s effective area (Sterling and Helweg 1990). The consequence is often a well that underperforms from the start or declines rapidly in output due to clogging or sand production.
Mechanical Surging: Active Development at the Screen Interface
Figure 3. Qualitative illustration of how multiphase flow (water and air) occurs in a casing during air development. As the water-air mixture reaches a density less than the water outside the casing, flow will occur to the surface (Sterrett 2007).
Surging is a mechanical development technique that uses a plunger or surge block (double or single) moved up and down within the well casing or screen. This action creates alternating positive and negative pressure pulses, causing water to flow into and out of the well screen through the surrounding filter pack.
This reciprocating motion is effective in mobilizing fine sediments trapped in the formation immediately adjacent to the screen, breaking up particle bridges and compacted zones that restrict flow.
Unlike airlift pumping, surging actively works across the screen slots, where water enters the well. By reversing flow across these slots, surging dislodges particles adhering to the filter pack and the borehole wall. This mechanical disruption increases the permeability of the formation near the well and ensures more uniform development across the entire screen length.
If surging is used in conjunction with pumping, you can get the advantages of the surging and be able to remove the fine-grained sediments at the same time. This type of development is one of the most effective methods of well development. The double surge block pictured in Figure 4 also has the capability for pumping and surging simultaneously.
Field Evidence: Johnson Driller’s Journal Case Study
Figure 4. Surge block is made of two rubber discs sandwiched between three steel discs (Sterrett 2007).
A valuable case study was published in the Johnson Driller’s Journal March-April 1980 issue. It provided empirical support for the use of over-pumping (equivalent to airlift pumping) and surging in well development and the open area of the well screen (Figure 5). The article documents findings from a project conducted at the Staples Irrigation Research Center in Minnesota, where a series of test wells were developed using different methods and evaluated for energy efficiency, drawdown, and screen performance.
The wells underwent a standardized sequence of development:
- Over-pumping for 20 to 30 minutes
- Mechanical surging
- Jetting and airlift pumping combined (airlifting was used to remove the fines above the jetting tool).
The testing revealed that wells developed with only over-pumping (essentially a form of continuous pumping similar to airlift) experienced rapid clogging, in some cases within 20 minutes of operation. These screens failed due to insufficient removal of fines and incomplete development of the surrounding filter pack.
Conversely, wells that underwent surging and airlift in combination exhibited dramatically improved performance. Efficiency testing showed energy savings as high as 80%, meaning less power was required to extract a given volume of water.
Wells that were underdeveloped demonstrated efficiencies as low as 30%, indicating significantly higher
operational costs and decreased lifespan due to excessive drawdown and wear on pumping equipment.
Figure 5. Development and open area (<15% and >15%) comparison and resulting specific capacity for Staples Irrigation Research Center study.
These findings highlight that surging not only improves the immediate output of the well but also contributes to long-term sustainability by lowering maintenance costs and energy usage. Additional development was performed with high-pressure jetting that further created a more efficient well.
Best Practices: Combining Surging and Airlift Pumping
While each method has its role, best practices in well development recommend a combined approach. Surging can be used first to loosen fines and break up particle bridges, followed by airlift pumping or jetting to remove the suspended materials from the well (Figure 6). This alternating cycle of agitation and removal is the most effective strategy for achieving full development of the screen and surrounding formation.
In addition, surging can be conducted with relatively simple and low-cost equipment, making it accessible even in remote or resource-limited settings. Manual or cable tool-based surge blocks are still widely used in field conditions where air compressors or jetting systems may be impractical. However, there are a number of contractors who are placing a pump between surge blocks to increase the effectiveness of development and reduce development times.
Conclusion
Figure 6. Action of a double surge block showing how energy is placed on the filter pack and formation to help remove fines and settle the filter pack (Sterrett 2007).
In summary, while airlift pumping plays an important role in removing water and suspended particles during well development, it is inherently limited to already developed zones and lacks the ability to mechanically disturb compacted fines near the well screen (Walton 1970 and Sterrett 2007). Surging, by contrast, is a proactive and direct method that targets the interface between the well and the aquifer, promoting more uniform development and higher long-term performance.
The findings from the Johnson Driller’s Journal demonstrate that incorporating surging into the development sequence significantly improves efficiency, reduces energy consumption, and extends the service life of the well. In addition, having more open area in the screen facilitates development resulting in more efficient wells. Combining surging with airlift pumping or jetting offers the best results—yielding cleaner, more productive wells that perform efficiently over time.
In smaller domestic wells with short screen sections, airlifting alone can provide good development, but I would incorporate some surging by turning the air on and off and letting the water fall back into the well to get some surging action.
References
Johnson Driller’s Journal. 1980. Well-Efficiency Project Yields Energy-Saving Data, March-April: 3–7.
Sterling, D.R. and Helweg, O.J. 1990. Well Development: A Comprehensive Review. Ground Water 28, no 5: 728–734.
Sterrett, R.J. 2007. Groundwater & Wells, Third Edition. Johnson Screens: New Brighton, Minnesota.
Walton, W.C. 1970. Groundwater Resource Evaluation. McGraw-Hill.
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Thomas M. Hanna, PG, is a technical director of water well products/hydrogeologist for Johnson Screens where he works in areas of well design, development, and well rehabilitation. He is a registered professional geologist in Arizona, Kentucky, and Wyoming and has worked for several groundwater consulting firms. Hanna can be reached at thom.hanna@johnsonscreens.com.
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