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In case the bottomhole pressure data is not available it is considered constant over time.

Motivation

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Production rate in producing well depends on its productivity index 

q^q_1^{\uparrow}(t)=J \cdot \left( p_e(t) - p_{wf}(t) \right)

and as such depends on lift settings 

It keeps declining due to to the offtakes:

p_e(t) = p_e[q^q_1^{\uparrow}(t), q_2^{\uparrow}(t), q_3^{\uparrow}(t), \dots]

and maintained by either aquifer or Fluid Injection and in the latter case depends on injection rates:

p_e(t) = p_e[q^q_1^{\downarrow}(t),q_2^{\downarrow}(t),q_3^{\downarrow}(t),\dots ]

The combination of 

The ultimate purpose of CRM is to correlate the long-term (few months or longer) flowrate history andinjection rates history with production rates history and BHP history (recorded by PDG).

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