Miscellaneous Subsurface Methods 



683 



trate the permeability surveys compared with drilling-time and core- 

 analysis data. 



In those wells where it is undesirable to use two fluids for the injected- 

 fluid-type survey or in those wells where it is desired to measure, the rate 

 of produced rather than injected fluids, either liquids or gas, an instru- 

 ment known as the "spinner" is used instead of the electrode assembly. 

 The spinner consists essentially of a housing in which a freely rotating 

 propeller is mounted on pivots. As the propeller is rotated by the flow of 

 fluids past the instrument assembly, each rotation is recorded at the sur- 

 face by means of an electric counting mechanism contained in the spinner 



504P 



-WELL NO. 

 4822 



^imif> 



m-\ 



40 00010 



SATURATION SPEC CAR INOCX 



•/.OIL ClPM/FT/PSI OIFF 



40 



SATURATON 

 %OIL 



00010 

 SPEC CAP INDEX 

 C.PM/FT/PSI DIFF. 



40 ao 



SATURATION 

 •/.OIL 



00010 

 SPEC CAP INDEX 

 0PM /FT/PS.I. DiFF 



40 60 

 SATURATION 

 % OIL 



00010 

 SPEC CAP INDEX 

 CPM/FT./PSI. DIFF 



Figure 369. Record of a pilot survey and core analysis. 



housing. The electric-pilot surface equipment and cable are used, the 

 only difference being in the data-recording meters. 



It is seen that knowledge of the variations in bore-hole size is essen- 

 tial to the accuracy of the spinner survey. This knowledge can best be 

 obtained through use of a caliper, another instrument run in conjunction 

 with the electric-pilot unit. This caliper is highly accurate, automatically 

 recording on a chart at the surface the irregularities in the bore hole. 

 Uses for the caliper other than to provide data for permeability and other 

 types of surveys are the following: (1) to locate packer seats in correct- 

 ing high gas-oil ratios or controlling water intrusion, (2) to gain informa- 

 tion for plastic plug-back work, (3) to determine the size of shot holes, 



