6 Advantages of Reverse Circulation Vs Direct Circulation On Bore hole drilling

hardrockdrills - Monday, June 11, 2018.
Enviado por hardrockdrills

In last article 8 Points on How to Select Water Well Drilling Rig, the Drilling method are mentioned, here we will give some further introduction on reverse circulation drilling system. The RC is widely used in borehole drilling area especially in water well drilling for big diameter hole.

Reverse Circulation(RC) Working Principle

  • The drilling theory of air reverse circulation is similar with the theory of drawing water with air compressor.
  • The air flows down the annulus between inner tube and outer tube and go inside single wall pipe right at air water mixer, where produces countless tiny bubbles. These bubbles going up along the pipe and expanding simultaneously. Due to the air continuing going inside the fluid, it formed lower density mixture of air and water upper the mixer. It leads the higher density fluid in the well go up with cuttings because of the pressure difference. In this way the cuttings are brought out of the well hole very fast.
  • Configuration of Reverse Circulation Borehole Drilling System

     

     

     

     

     

     

     

     

     

     

     

     

     

    Here are the main advantages of RC(reverse circulation) drilling compared to DC(direct circulation) drilling:

  • High Drilling Efficiency
  • The Velocity of cuttings flowing up is 10 – 50 times faster than direct circulation drilling
  • According to the historical data, for clay layer the drilling speed achieves 12 m/h maximum
  • For sand it is 20 m/h
  • For gravel cobble it is 1 – 1.5 m/h.
  • For f 4 – f 6 level rock condition it is 1 – 3 m/h.
  • In general, drilling speed is 1.2 – 3 times faster than direct circulation drilling.
  • 2. Giving sampling faster and more accurate

  • The direction of flushing air flowing is same with direction of core going inside tube, which cuttings are not contaminated by sloughing formation off the hole walls.
  • It helps to get integrated core and giving an accurate formation log
  • 3. High ratio of actual drilling time/ preparing time

  • For rock formation, when drilling with tricone bit, the actual drilling time/whole rig working time is around 80 – 90%
  • 4. High quality well hole achieved

  • Less deviation on hole diameter from top to bottom.
  • Clean on well bottom and less slope of well. All of these can lead to higher water yield.
  • In average, it is 2 times less than direct circulation for time spent for washing well, meanwhile one third higher water yield compared to direct circulation
  • 5. Lower drilling cost

  • The reverse circulation drilling has higher drilling efficiency, and can get better quality well hole and longer life time for drill bit.
  • The total cost is lower –  compared to direct circulation drilling, it is around $5 lower per meter.
  • 6. Larger diameter hole can be drilled

  • Drillers usually use it to drill large diameter hole due to it is easier and faster to clean the hole, especially for softer formation.
  • Above is all about the comparison or difference between Reverse circulation and Direct circulation regarding bore hole drilling . For most of our water well drilling rig, it suit for both reverse circulation and direct circulation drilling tools such as truck mounted drilling rigCrawler DTH mounted drilling rig

    In next blog we will give introduction on how to select or design the high level reverse circulation drilling system.

    More Articles:

  • 8 Points on How to Select Water Well Drilling Rig
  • Market Survey Metals – Iron Ore
  • Market Survey Metals – Bauxite, Alumina, Aluminium
  • 7 Rules of Thumb for Open Bit Blast Pattern
  • Mineral Commodity Summary
  • Down The Hole Drilling Trouble Shooting – Bit Damage
  • Down The Hole Drilling Trouble Shooting – Hammer Piston Casing Breakage
  • Down The Hole Drilling Trouble Shooting – Treaded
  • Selection of DTH Drilling Tools
  • Acerca de hardrockdrills

    Shanghai Hardrock Drills Co.,Ltd is located in Shanghai, who is dedicated in designing and manufacturing the drilling rigs. The rigs have been widely used in water well drilling, soil sampling, geotechnical testing, mine exploration, foundation drilling, geothermal drilling, etc.

    Our drilling rigs are easy to set up, operate as well as maintain. And we always put the quality on the top. We use the 3-d software to design and FEA software for simulation to insure our products are strong enough, but not overdesigned to reduce cost.  Every individual component is inspected and each machine is tested carefully by our quality people before shipping to customer.

    Shanghai Hardrock Drills Co.,Ltd has a powerful technical force and fine equipment, it’s leading in the products design, workmanship and production capability, it’s capable to design, manufacture, and assure the quality of whole series of drilling rigs. The products are sold to over thirty countries and regions including Asia, Africa, Europe, and South America. Shanghai Hardrock Drills has been ISO9001 quality system and national CCC certification approved.

    We are dedicating to BUILD TRUST with customer and find new ways of working not only to meet customer specific requirement,  but also get their job done more easily, efficiently and economically.

    Considering the application condition in developing country especially for those remote area, our product is designed to be easier for transportation and best price / performance ratio.

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