The Logic Behind The Magic. “Production Well"

A well drilled to find and produce oil or gas in an unproven area  to find a new reservoir

Reservoir development process is comprises of 5 phase:

1. Well construction

2. Drilling

3. Casing

4. Cementing

5.  Completion

At the completion phase, well head is installed.
Wellhead is installed at the surface of the well containing an assembly of hangars and seal to support the weight of casing string hang for it and to contain well pressure.
Well head is also used to control liquid flow from inside or outside the well.

 A typical well head composed of 3 controlled valves:

1. SCSSV (Surface Controlled Sub Surface Safety Valve)

2. MV (Master Valve)

3. WV (Wing valve) / Annulus Wing Valve (AWV)

All of these three controlled valve are controlled by Well Head Control Panel (WHCP)
All of these valves are also designed for fail closed i.e,. if there is loss pressure in hydraulic supply line. SCSSV, MV, and WV will be closed.    

The typical logic for WHCP are:
1. If Fire & Gas and ESD alarm occurs, SCSSV shall be closed
2. If Process Shutdown occurs, WV shall be closed.
3. The sequence of opening valve is SCSSV-MV- WV/AWV, while the sequence if closing valve is WV-MV-SCSSV-AWV.
 4. Start-up By pass can override PSD signal
5. If the open and closed signal is not active. SCSSV, MV, and WV is open.

Sample of the logic is shown below: