Does extracting Oil from the ground leave just an empty space?

Question

Does extracting Oil from the ground leave just an empty space?

Answer 1

No it's not a cave-like empty space down there.

For a very basic description, the Oil, Gas and water are contained in the Pores of formations of 'Porous' rocks like sandstone, deep underground.

The Oil, Gas and Water 'Migrate' upwards through the pores (similar to the way water will trickle through a sponge).

They migrate upwards until at some point they come to a Non-porous 'Cap-rock' where they build up high pressure.

The water settles at the bottom of the formation and the Oil and Gas continue to pass upwards through the water with the oil forming above the Water and the Gas above the Oil.

Pressure continues to build as more and more gas collects at the top of the formation below the Cap-rock.

When a well is drilled and completed, a 'Christmas Tree' (The Well Head) of piping and valves is constructed on the surface connected to the casing and tubing pipes that are inserted into the well-bore during drilling.

The pressure difference between the reservoir and the surface equipment give the necessary 'Lift' to the fluids to produce the well into the receiving vessels for separation of the well products.

(To one of the answerers, AIR is NEVER pumped down into an oil and gas bearing formation. In some cases where a well's production is dropping off, a Gas-lift injection system or a Water-flood system is employed to revitalise production).

Answer 2

This is a good question, usually they do not leave the empty reservoir empty, other wise it could collapse under the massive earth pressure, that is why they inject water to maintain the pressure balance, and rarely they inject gas.

Answer 3

mud is only pumped down during the initial drilling to cool the drill bit and bring debris up----it other purpose is too prevent an uncontrolled gusher

usually when you first 'strike' oil it is under pressure, hence 'gusher'

but eventually you can only pump it out slowly to allow water time to replace the oil

alternatively (if surface water is available) too speed things up, you can pump water (or air but not as effective in the long term) down as you pump oil up

Answer 4

no it's filled either with mortar or soil

Answer 5

No. That's not possible.

Unless the oil is replaced by water, the formation subsides.

Water injection also helps harvest the oil in some formations.

Answer 6

The rocks that contain oil are generally porous sandstone.   They are still "rocks" in the sense that they seem solid if you look at a drilled core sample.  Good oil sandstone can have porosities in the 20-30% range.  That means that 70-80% of the rock is solid material, with 20-30% being space inbetween the solid particles.   The space is taken up by oil.  There are no underground "pools" of oil, like a swimming pool or a lake holds water.

When oil is extracted from sandstone, the spaces inside the rock are sometimes left empty, but more often, in order to get more out of the rock, salt water is pumped under high pressure to force the oil out.  The salt water is left underground.  This is OK, because most oil deposits sit above a large amount of salt water, anyway.

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Answer 7

Usually course cut silica sand, which is round is used to displace it. Empty space on this planet is reserved for Politicions

Answer 8

I think it's usually forced out under pressure.

If there is insufficient natural artesian pressure to force it out, then water is added (as oil floats on top) If there is natural pressure then it fills back up (with water, or more oil?) on it's own.

Also the rocks that the oil is contained in an aquifer/ are porous, so there will still be some rock remaining. (but the rock remaining will have less to support them, could cause problems with settling over time)

Not quite the same, but I feel partially relevant. Sulphur can be extracted as liquid, by pumping steam/air underground. the steam melts the sulphur, and the steam/air/sulphur mix bubblesup to the surface. This CAN create large "voids" underground, and I have heard that at least one sulphur processing plant "disappeared" into the ground, because it was built over the top of the sulphur deposit (Think it was in Lancashire/Cheshire, UK. but it may well be an chemical engineering myth!)

Answer 9

no I believe they extract it under pressure they pump mud down and get oil out, that how they have prolonged the life of dead wells,and by drilling at angles not just straight down