Subsurface Logging Methods 



497 



replace the fluid in the drill pipe is calculated, and this time subtracted 

 from the round-trip time will give the sample-lag time at that particular 

 depth. Two clocks are mounted in a panel, one clock showing the correct 

 time, and the other set back to allow for the sample lag. When the hands 

 on the second clock show the time that a certain depth was drilled, cuttings 

 are collected for that interval. Thus all tests and examinations are made 

 from the true depth. 



Figure 233. View of a sample separator within laboratory. Geologist has collected 

 uncontaminated cuttings from predetermined depth preparatory to examination 

 and testing for oil or gas. 



until they are clean. A measured amount of cuttings is put into a con- 

 tainer, which is filled half full with fresh water. The container is con- 

 structed with blades in the bottom, which revolve at a very high speed, 

 pulverizing the cuttings. This has the effect of exposing the pore spaces 

 within each chip. Any gas that might be contained in the pores or might 

 adhere to the sample is released by the agitation and brought to the sur- 

 The cuttings for each two feet are washed and decanted several times 

 face of the water. A measured amount of cuttings is put into a container, 

 which is filled half full with fresh water. The container is constructed with 

 blades in the bottom, which revolve at a very high speed, pulverizing the 

 cuttings. This has the effect of exposing the pore spaces within each chip. 

 Any gas that might be contained in the pores or might adhere to the sample 

 is released by the agitation and brought to the surface of the water. By 



