Fracking Technology

Hydraulic stimulation

To enhance the flow of gas or oil wells and exploit the potential of the deposits more efficiently, wells in production are stimulated hydraulically.

Injecting a fluid under high pressure and at a high flow rate at a specific point inside the well causes cracks to be formed within the rock – the so-called “hydraulic fracturing”. During the fracturing process, the crack measuring about 100 metres in length is filled with proppant agents (bauxite beads) to stop the crack from closing again.

This method of deliberately fracturing the rock increases the drainage area for the gas or crude many times. Gas or oil is then able to drain from the rock into the crack and flow into the well. The now highly permeable flow path to the well means less energy is expended, and the natural gas or oil can therefore be extracted from the deposit more efficiently.

Read more »

Recovery

1. Primary recovery

After the well has been drilled into an oil-bearing reservoir and the mud depleted, the natural pressure in the reservoir causes the oil to flow into the production wells and then gush to the surface.

If reservoir conditions are difficult, e.g. rapidly declining pressure or significant flow-resistance factors, this so-called gusher soon stops. The simplest way of maintaining production flow rates is to use downhole pumps. These phases in the production of oil from a field are known as primary recovery. On average, around 5-10% of the original oil in place can be exploited by means of primary recovery.

2. Secondary recovery

Secondary recovery methods were developed to improve the recovery factor. The most common method involves flooding the reservoir with water. This involves injecting water into the reservoir to artificially increase the reservoir pressure and press the oil into the production wells. This process is "reversible" in that gas can be forced into the top of the reservoir and thus press the oil down to deeper production wells. The recovery factor can be increased to around 45% by employing the water flooding method.

Read more »