Well Controls and Shutdowns

A down-hole safety valve (DSV) is located underground. This is a self-contained valve that operates on high flow and does not require external signals or power for its operation. The valve is normally open, and closes automatically when its differential pressure reaches a predetermined value. Based on the flowing capabilities of the well, each valve is adjusted to accommodate the fluid, pressure, temperature and flow rate of the well. 

The lower master, upper master, wing, and flow-line valves are hydraulically operated. Loss of hydraulic pressure will cause the valves to close. 

In a proposed design each well has two independent shutdown systems, i.e., ESDI and ESD2. 

Associated with each well are numerous safety instrumented functions. Some of the common functions are  

Prior to carrying out SIL verification calculations for Safety Instrumented Functions (SIF) it is essential and very important that each function and its associated input and output signals be weU defined. The identification of the SIF is part of the analysis phase and the detail requirements for each function are documented in the Safety Requirements Specifications (SRS). 

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