Conditions for zero value of SIDPP

There are some condition when we don’t have SIDPP (0 or very low value of sidpp) or are unable to see it.
  1. If there is float valve in drill string or casing. Float valve is a NRV (Non return valve) installed in drill string or casing and allows fluid flow in one direction only. In this case there is shut-in pressure but float valve dosent allow it to transmit through itself due to which shut-in drill pipe pressure is not seen at surface. To measure SIDPP in this case, we need to follow a procedure called Float bumping.
    float valve
  2. If drill string or casing is plugged, shut-in drill pipe pressure is not seen at surface. Also as the drill string is plugged it’s not possible to pump drilling fluid through the string. In this case it’s not possible to follow Driller's Method or wait and weight method and we have to go for volumetric method which involves pumping the mud through the annulus using kill line. And the formation pressure and kill mud weight is calculated using shut-in casing pressure (SICP) and hydrostatic pressure on annulus side.
  3. If there is no drill pipe shut-in pressure (DPSIP or SIDPP both are same) which happens when the formation pressure is completely balanced on the drill string side but not on the annulus side. In that case simply circulating Drill string mud through annulus and to surface is going to balance the BHP from annulus side too.
    shut in pressure
In the first two cases we had shut in drill pipe pressure but due to float and plugging that pressure is not felt at surface and the guages will show '0' value. While in third case SIDPP is actually zero.

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