Flow control Valve (FCV)
Stepping up, the next option is to employ a downhole Flow Control Valve (FCV) that can be either manually or automatically (via PLC) controlled from surface by means of the surface control system (SCS).
This system allows the user to control the injection pressures and flow rates to desired levels and alarm when the injection system is at fault. Typically the system is configured by means of a PLC that will allow the user to specify the desired injection flowrate provided the injection pressure remains within a set band of allowable pressures. The valve will modulate open and closed by way of surface pumps, valves and controls within the SCS trying to achieve the desired injection flow rate.
If the system falls outside of the desired injection pressures, the system can be configured to alarm such that the required action can be taken. Such faults may be:
1. FCV modulated fully open with injection pressures above maximum set pressure and desired injection flow rate not obtained. This fault would be caused by a blocked or fouled bore that is not taking the desired flow rate.
2. Injection pressure falling below minimum set point. This fault signals a problem with either the FCV, SCS or PLC controls resulting in injection water possibly cascading into the bore and entraining air which can result in subsequent air-fouling, bio-fouling or calcite formation.
All water bore equipment is manufactured from stainless steel materials and potable water grade rubber compounds compliant to AS/NZS:4020.