Question

explain the process of extraction of natural gas and petroleum​

Answer 1

Answer:

Deposition of petroleum occurs with natural gas in the rock called oil Wells from where it is taken out by drilling.

Answer 2

Formation of natural gas and crude oil

Well over 200 different hydrocarbons can be identified in a sample of crude oil. They were formed in remote periods of geological time, anything from 50 to 500 million years ago, from the remains of living organisms. It is, therefore, a fossil fuel.

Weathered rock material, eroded from land masses and carried to the sea, accumulated in layers over millions of years in subsiding basins, and the remains of large quantities of marine plant and animal organisms became incorporated in the sediment (Figure 1).

Owing to the thickness of the sediments, high pressures built up which, probably in conjunction with biochemical activity, led to the formation of petroleum. The detailed mechanism is obscure, but it is probable that anaerobic microbes lowered the oxygen and nitrogen content of what had been living matter.

Subsequent earth movements which caused uplift of the sedimentary basins also caused migration of the petroleum through pores in the rocks, sometimes to areas far from where it was formed. In the course of migration, some of the petroleum accumulated in traps where the permeable rock was bounded by impermeable rock. The principal types of trap in oil fields found all over the world are the anticline (an upfold in the strata) as shown in( Figure 1) the fault trap (Figure 2) and the salt dome (Figure 3).

Anticline (an upfold in the strata) ( Figure 1)

Figure 1 An anticline is where previously flat strata have been bent upwards by earth movements to form an arch. In this case the petroleum has migrated upwards in the permeable rock and become trapped by the overlying impermeable rock.

The fault trap(Figure 2)

Figure 2 A fault line is the line along which the strata on one side has been displaced and is no longer aligned with the strata on the other side. In the example depicted here a layer of impermeable rock has trapped the petroleum by preventing it migrate further in the layer of permeable rock./span

 The salt dome (Figure 3)

Figure 3 Rock salt, when subjected to heat and pressure, can move very slowly upwards forcing its way through the overlying rock strata and so forming a salt dome. In the case shown, petroleum in the layer of permeable rock has become trapped by the overlying impermeable rock and the salt dome.