This discussion centers on the feasibility of completely removing air from a borehole to eliminate pressure changes during drilling operations. Participants clarify that achieving a hard vacuum is challenging and that the presence of formation fluids, which are incompressible, maintains pressure regardless of air removal. The consensus is that simply sucking air out of the hole will not prevent pressure influx from formation fluids, as the pressure is inherent to the geological conditions, not dependent on the presence of air.
PREREQUISITESThis discussion is beneficial for drilling engineers, geologists, and anyone involved in oil and gas extraction who seeks to understand pressure management and the dynamics of boreholes.
He's talking about boreholes for wells drilled into the ground, which are typically filled with water up to the water table. He seems to be asking if air can be removed (a second phase) from below the water level. Most wells for oil and gas production have a pipe running down the center of the borehole that is cemented in place to the surrounding geological formation (except at the very bottom few meters). Where this air would be located and how it got there would be the puzzle to me.CWatters said:The word completely in the title suggests removing 100% of the air leaving a vacuum. Hard vacuums are difficult to produce. What are you trying to achieve?
I stand corrected.ahmed11 said:i mean when if i drill with a small machine underground and seal off the hole after machine is set underground and all air is sucked out, will that eliminate the change in pressure. the machine will be underground and no air will be to enter the hole from the surface so that will cancel the change in influx and resulting in a kick, right?(my theory is that pressure of any kind is present when air is, i think)
i'm just thinking out loud here so would really appreciate your help.
thanks..
I'm really not able to even come close to understanding what you are asking.ahmed11 said:so do you think my theory is correct?
i don't know if it was stated before or not, i tried looking online but couldn't find anything
in usual drilling operations, drilling fluid is pumped into balance the formation pressure in order not to get a kick( change in influx rate from formation fluid and gases) and blowing. so instead of using drilling fluid which is more dense than the formation pressure we could suck air out of the hole when a small machine( a single machine like a small car for example) is set downhole and then seal off the hole. like drilling through an air free rock in outer space, if the rock isn't injected with air( drilling pipe) no matter the fluids in it, it won't change the ratio of pressure already present.Chestermiller said:I'm really not able to even come close to understanding what you are asking.
No. And I have some experience with drilling mud and formation fluids.ahmed11 said:in usual drilling operations, drilling fluid is pumped into balance the formation pressure in order not to get a kick( change in influx rate from formation fluid and gases) and blowing. so instead of using drilling fluid which is more dense than the formation pressure we could suck air out of the hole when a small machine( a single machine like a small car for example) is set downhole and then seal off the hole. like drilling through an air free rock in outer space, if the rock isn't injected with air( drilling pipe) no matter the fluids in it, it won't change the ratio of pressure already present.
am i making any sense here?
ahmed11 said:in usual drilling operations, drilling fluid is pumped into balance the formation pressure in order not to get a kick( change in influx rate from formation fluid and gases) and blowing. so instead of using drilling fluid which is more dense than the formation pressure we could suck air out of the hole when a small machine...
ahmed11 said:am i making any sense here?
yes that's exactly what i mean. i know that air is less dense than the drilling fluid but if there is no air inside the hole from the beginning then oil and gas will be less dense therefore it won't blow up to the surfacenasu said:He may think that if there is no air there is no pressure. Based on this quote:
"(my theory is that pressure of any kind is present when air is, i think)".
can u explain why would it be wrong?Bystander said:Wrong. Formation pressure is formation pressure.
ahmed11 said:yes that's exactly what i mean. i know that air is less dense than the drilling fluid but if there is no air inside the hole from the beginning then oil and gas will be less dense therefore it won't blow up to the surface
right?
Chestermiller said:What makes you have this strange idea that the formation fluids will be less dense? Formation fluids are virtually incompressible.
ahmed11 said:yes that's exactly what i mean. i know that air is less dense than the drilling fluid but if there is no air inside the hole from the beginning then oil and gas will be less dense therefore it won't blow up to the surface
right?
The hole is not completely void. It is filled with formation fluid up to the water table. If you tried to pump the water out of the hole, it would just flow out of the surrounding porous rock and fill up the hole again.brotherStefan said:It seems to me that at these depths, if the hole could somehow be completely voided, would not the surrounding pressure collapse the hole?