PRODUCTION PROBLEMS 



1139 



pump being set too high in the well, while the pounding due to gas-locking 

 may occur when a high fluid level exists above the pump. 



For the maximum rate of recovery, the bottom-hole pressure usually 

 should be reduced as much as possible, and this can be achieved by main- 

 taining the lowest practical fluid level. In actual pumping operations, 

 it is not possible to obtain the full theoretical production rate due to the 



40 60 



Shut-in time.hr 



Fig. 706. — Plot oi p^ — p versus shut-in time. 

 The data for this semilogarithmic plot were obtained 

 from Figure 410. (Muskat, A.I.M.E. Petroleum 

 Technology.) 



hydrostatic head that must be maintained in order to feed the oil into 

 the pump. The factors on which this head depends must be determined 

 for each field and include viscosity of the oil, pump speed and capacity, 

 valve design on pump intake, etc. 



After making changes in pump speed or capacity, it is advisable to 

 run a subsequent fluid-level measurement to be certain that the proper 

 draw-down is being obtained. 



OTHER APPLICATIONS OF FLUID-LEVEL MEASUREMENTS 



Field Development Studies. — Shut-in reservoir-pressure data are often presented 

 on maps showing lines of equal bottom-hole pressure, generally expressed with refer- 



