All language subtitles for p5

In abnormal pressure.

There is something that stops the transfer of fluids

from one side to the other a barrier if you will.

Let's go back to the fish.

The water level is fixed by a barrier but there is

still layers of rock over him.

He feels the overburdened pressure of the rock but

because the water level of stop from rising as it

normally would and a simple displacement by a barrier.

The fish will now feel increased water pressure.

The impermeable barrier prevents the water from

squeezing out at the lower intervals causing the

prosody and poor pressure to be greatly higher or

lower than expected.

It is important for us to know the various pressures

of our zones as we drill deeper.

Hitting an area of greatly increased pressure that

we are not prepared for can be very dangerous.

Drillers constantly monitor the down whole pressure.

For this very reason.

In this picture we have a trapped reservoir with

normal pressure.

In the reservoir we have a little bit of oil and lots of water.

When we drilled into this reservoir what will happen.

Will we need a pump for the oil to flow.

Or a pump for the water flow.

Or a pump for both.

Let's look at what happens when we drill into the water.

In this picture we've drilled into an empty decline

structure full of water at a depth of ten thousand feet.

The pressure at the surface is fourteen point seven

ps i.

To calculate the pressure of the water at a depth of at

ten thousand foot whole we use the formula which is

pressure equals water gradient times depth.

Or.

P equals zero point five pm cyber foot times ten

thousand feet.

To calculate that the pressure is five thousand peer side.

Now inside the pipe the pressure is equal to the

pressure at the surface.

So like with the you tube at the end of our pipe we have a

closed valve or door and when i opened the valve in the

you to the water will rise because of the pressure.

Differential of fourteen point seven ps.

I at the surface and five thousand and ps i at the valve.

Which forces the water up.

But how high will it go.

With simple salt water it will make it almost to the surface.

Let's go back to our you tube.

Again with only water what will happen if i keep

adding water from one side with the valve open.

Both sides would fill to the top and then it would

spill out on the left hand side.

Now remember what happened when i added oil.

The level of the fluid on the side with the oil rose higher.

Now if i keep adding water the side with the oil will

gush up and out before it overflows.

Let's go back to our reservoir with the same depth and

the same pressure at the surface and at ten thousand feet.

This time we put our pipe just in the oil.

When we open the vow the oil will gush out because the

whole column of oil will be less than five thousand

and pierre say because oil has a lower gradient or

lower density.

He then water.

Because the oil is lighter than water the oil is

pushed up and up.

How high will the pipe need to be so that it is balanced

with the p aside from the oil and p aside from the water.

We really don't care as long as we can get it to the

surface so to answer the question of whether we need

to pump to get on oil to the surface.

The answer is no the normal pressure of oil at the

bottom of the whole was enough to push it to the surface.

Gas will come out even faster because it's density is

even lower.

Now let's look at a reservoir with abnormal pressure

in an artesian over pressure.

In this picture of abnormal pressure we have drilled

into our reservoir in an antique klein.

But this time we have an outcrop.

It could be a one hundred kilometers away.

In this example the oil is trapped in a shallow and to

climb but outside water from rain is able to

penetrate the formation.

Let us introduce an energy formula we need to talk

about potential energy of a formation.

Pressure is defined as force divided by area or rewriting.

It can be written as energy divided by volume or weekend.

In this case we're talking about potential energy p a

divided by volume.

Now he can be written as mgh giving us an m g h divided by volume.

And am divided by volume is defined as density or row.

So now we get pressure equals row g h.

Where geez the gravitational constant.

An h is the height of the water.

The higher age is the more it is going to push on the aisle.

This can be very dangerous when you drill into an area

of abnormal pressure because it can explode out.

This is a good example of artesian over pressure.

Abnormal pressure can arise from several methods.

Number one artesian water flow which we just showed you.

Number two deep burial of unconsolidated sediments.

Number three folding in mountain front areas.

Number four very deep sandstone burials.

And number five ceiling of pours and chalk formations.

Drilling engineers must always be on the lookout for

these conditions.

These various types of abnormal pressure will be

discussed later when we talked about drilling a noir well.

In this chapter we discussed the basics of the

origins of petroleum.

The basic chemical compositions of petroleum

reservoirs and reservoir rock properties things

like prosody palm ability and fluid saturation.

We talked about the migration of oil from a source

rock into a resume or rock and what is an oil trap and

types of our traps.

Structural and stratigraphic or we also talked

about reservoir pressure.

The energy to push out the oil we have normal pressure

which is a function of depth.

We have abnormal pressure which is high overburden pressures.

All these topics are important to the petroleum

engineers that drilling engineer who's drilling

the oh well.

The production engineer who producing the oil and

the reservoir engineer who monitoring the oil fields.

This is the end of chapter to the overview of

petroleum industry.

Or.

Oh.