Hebrew

Drilling Chronicles

Originally, a number of private drilling companies operated in Israel. After the establishment of the State, Mekorot, together with the Novak Company, set up a joint drilling company named Water Works. The employees of the company were mainly Holocaust survivors from Poland, who were experts in the field of drilling; and the drilling rigs and other machinery dubbed with Polish names. During this period, boreholes were drilled to depths of 40 to 500 meters, using the “percussion” method.

 

In the mid-1950s, Water Works purchased two large rotary drilling rigs to drill for oil, and conducted the first oil drilling at Heletz 1 in 1955. The company was liquidated in 1958 and its employees were hired by HME.

 

In order to plan drilling projects and to support and assist the drillers, the “Drilling Site” unit was set up at Mekorot HQ as part of the Technical Dept. (currently part of the Mekorot Engineering Services Unit). At the end of the 1990s, a hydrology department was also established, which, together with the drilling department, establishes, supports and oversees Mekorot drilling operations.

 

 

 

New equipment was developed as part of the efforts to improve the quality, depth and numbers of boreholes. Some of these are global innovations. Thus, For example, from the mid-1970s, salicylic acid was used, to dissolve limestone rock strata, in order to increase output from the boreholes. The implementation of this method significantly increased the quality of the boreholes drilled in limestone and dolomite rock strata,  using the rotary method, which facilitated the drilling of boreholes to unlimited depths. The use of salicylic acid and the subsequent deepening of the boreholes brought about a 75% increase in the output of the boreholes compared to similar boreholes that were not treated with this method.

 

Concurrently, new devices were developed and incorporated, such as stainless-steel Johnson filters to reduce the problem of sand falling into the shaft in boreholes when drilling through sand strata the use of non perishable metal equipment and new chemicals, and the integration of new drilling techniques suited to the various types of rock, such as basalt rock, etc.

 

The use of enhanced equipment as well as the purchase of new rotary drilling rigs and reverse circulation rigs, also led to a significant reduction in drilling times, an improvement in the quality of the boreholes and the strengthening of Mekorot’s credibility and status as the leading company in the field of water supply in the world.

 

 

 

Drilling of the Zohar 16 borehole using an MR-5000 Drilling Rig. 

 

Over the past few years, EMS Mekorot Projects has specialized in the field of refurbishing boreholes. It is well known that boreholes are the major source of water in the State of Israel, and Mekorot runs about 1,100 such water producing boreholes. Boreholes, like any engineering structure, require occasional refurbishment. Therefore, EMS Mekorot Projects invests a great deal of resources in dedicated equipment and in the training of skilled teams in the revamping and refurbishing of boreholes.

 

Two objectives are achieved upon the completion of the refurbishing process: An increase in the flow discharge rate and an improvement in energy efficiency.

 

Reasons for a decline in the output of a borehole and the need for refurbishment action can be:

 

       Chemical blockage: 

  • the chemical composition of the water

 

       Biological blockage:

  • The presence of bacteria and organic materials in the water 
  • The presence of Mg. Fe and S in addition to the composition of the water 

       Mechanical blockage:

  •  Blockage by [grindings sand, clay and loam as the result of the   collapse of  strata.

 

       Physiochemical blockage:

  • Sedimentation of thin fragments of the strata..
  • Sedimentation of salts (scale).

 

 

 

Refurbishment Techniques

 

1

Mechanical

¨       Piston

¨       Water jet

¨       Compressed air pumping

¨       Over pumping

 

 

 

2

Chemical

¨       Introducing chemicals into the shaft and pumping to drain them

¨       Polyphosphates

¨       Acids

 

* In order to obtain optimal results, refurbishment should combine the two techniques: First mechanical refurbishment followed by chemical sluicing.

 

Jump to page content