# How do they drill though 5000 feet of water? **URL:** \ **Category:** Factual Questions\ **Created:** [May 26, 2010, 7:28pm UTC](https://boards.straightdope.com/t/how-do-they-drill-though-5000-feet-of-water/540864 "2010-05-26T19:28:16Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Bijou\_Drains](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bijou_drains/32/2814_2.png) [@Bijou\_Drains](https://boards.straightdope.com/u/Bijou_Drains)\ **Post date:** [May 26, 2010, 7:28pm UTC](https://boards.straightdope.com/t/how-do-they-drill-though-5000-feet-of-water/540864/1 "2010-05-26T19:28:16Z")
It seems like to me that the drill pipe would flex and other problems would arise due to being in a liquid rather than solid soil or rock. I guess they know how to do this but do they have to use a lot different equipment than they use to drill on land? ---
**Author:** ![Munch](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/munch/32/5281_2.png) [@Munch](https://boards.straightdope.com/u/Munch)\ **Post date:** [May 26, 2010, 7:35pm UTC](https://boards.straightdope.com/t/how-do-they-drill-though-5000-feet-of-water/540864/2 "2010-05-26T19:35:15Z")
> [@Bijou\_Drains](#): > > It seems like to me that the drill pipe would flex and other problems would arise due to being in a liquid rather than solid soil or rock. > > I guess they know how to do this but do they have to use a lot different equipment than they use to drill on land? Huh? The bottom of the ocean is soil and rock as well. ---
**Author:** ![awldune](https://avatars.discourse-cdn.com/v4/letter/a/c77e96/32.png) [@awldune](https://boards.straightdope.com/u/awldune)\ **Post date:** [May 26, 2010, 7:38pm UTC](https://boards.straightdope.com/t/how-do-they-drill-though-5000-feet-of-water/540864/3 "2010-05-26T19:38:41Z")
> [@Munch](#): > > Huh? The bottom of the ocean is soil and rock as well. But you have a mile-long length of drill shaft that is basically unsupported. I wonder about this too. ---
**Author:** ![Bijou\_Drains](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bijou_drains/32/2814_2.png) [@Bijou\_Drains](https://boards.straightdope.com/u/Bijou_Drains)\ **Post date:** [May 26, 2010, 7:40pm UTC](https://boards.straightdope.com/t/how-do-they-drill-though-5000-feet-of-water/540864/4 "2010-05-26T19:40:00Z")
The drill pipe has to pass through 5000 feet of water before it hits the bottom of the ocean - that’s what I mean. Ocean water has currents for 1 thing that can push the pipe around. The water does not just sit there. ---
**Author:** ![DCnDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dcndc/32/2842_2.png) [@DCnDC](https://boards.straightdope.com/u/DCnDC)\ **Post date:** [May 26, 2010, 7:47pm UTC](https://boards.straightdope.com/t/how-do-they-drill-though-5000-feet-of-water/540864/5 "2010-05-26T19:47:21Z")
[Here](http://www.naturalgas.org/naturalgas/extraction_offshore.asp) is a pretty good explanation of the different types of offshore rigs. It would seem that the drill is not necessarily lowered down 5000 feet from the surface, but from a substructure some ways down into the water. ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [May 26, 2010, 8:42pm UTC](https://boards.straightdope.com/t/how-do-they-drill-though-5000-feet-of-water/540864/6 "2010-05-26T20:42:36Z")
Nice link DC, I especially liked the diagram showing the different types of drill rigs in different depth waters. Here is a link to specifications for the [Deepwater Horizon](http://www.deepwater.com/fw/main/Deepwater-Horizon-56C17.html?LayoutID=17) rig, saying it was a semi-submersible rig. The riser is the portion that Bijou is talking about; it would have to be designed to handle the currents and other forces (such as bending) underwater. ---
**Author:** ![matt](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@matt](https://boards.straightdope.com/u/matt)\ **Post date:** [May 27, 2010, 2:00am UTC](https://boards.straightdope.com/t/how-do-they-drill-though-5000-feet-of-water/540864/7 "2010-05-27T02:00:20Z")
One thing you have to appreciate is that the drillstring is under _tension_. The drill bit is pushed into the rock by the weight of the drill collars, very heavy section steel tubes just above the bit, and the collars are _hanging_ off the drillstring. Nothing is pushing down from the top. That said, there’s a huge amount of the mechanics of drilling that I don’t know or don’t understand. If there’s any drillers or rig engineers on the Boards, feel free to open an “Ask the…” thread.