Duties and Reports of the Subsurface Geologist 817 



1:40 p. m. 330 Mcf 2:15 p. m. 306 Mcf 



1:45 p. m. 340 Mcf 2:20 p. m. 319 Mcf 



1:50 p. m. 296 Mcf 2:25 p. m. 314 Mcf 



At 4:30 p. m. (16th), increased flow bean setting from 8 to 12/64'". While 



on gauge from 5:25 to 7:45 p.m. (2 hrs. and 20 min.), well produced a total 



of 12.59 bbls. of fluid (5.4 B/H or 129.6 B/D rates). The tubing head flow 



pressure varied between 90 and 110 psi. Trap pressure 50-60 psi. No cut was 



taken during this gauge. 



At 8:00 p. m. on June 16th, pumped 193 cu. ft. of 82-lb. mud into tubing 

 forcing hole fluid in tubing back into formation. Pulled packer loose at 

 9:00 p. m. 



Gas Samples 



Where newly discovered oil- or gas-bearing intervals are evaluated 

 by means of a formation test or a conventional production test, repre- 

 sentative samples of the oil and gas should be collected in suitable con- 

 tainers to be subjected to complete analysis later. 



7^65^5 for Oil 



All sands concerning which there is any question of their possible 

 productivity should be tested for oil and gas. Such tests can be made in 

 various ways. In the case of a core, the sample tested should be taken 

 from the interior to avoid exterior contamination. Chloroform, ether, and 

 carbon bisulphide as solvents of petroleum are used for making these 

 tests. In the procedure a few cubic centimeters of the crushed sample is 

 placed in a test tube, enough solvent is added to cover the sample, and 

 the test tube is shaken. If petroleum is present, the liquid will show various 

 shades of brown, the shade depending on the amount and type of petroleum 

 present. A doubtful or faint test can sometimes be confirmed by slowly 

 dropping the supernatant liquid from the test tube on a piece of filter 

 paper. If the test is positive, a dark ring will form around the periphery 

 of the expanded drop when the paper has dried. 



In the event very light-fraction oils are involved, a more delicate test 

 is made with acetone. This test is carried out by placing about 10 cc. of 

 the sample in a test tube and adding 20 to 30 cc. of acetone. After the 

 mixture is shaken, 20 to 30 cc. of distilled water is added. The presence of 

 oil turns the liquid milky. As this is a delicate test, an oily thumb held 

 over the test tube during the shaking will frequently give a positive test. 

 A positive acetone test cannot be considered as absolute proof of the pres- 

 ence of oil, but a negative one will prove its absence. 



Salinity Test 



A salinity test should be made on the drilling fluid periodically, 

 preferably not less frequently than every 24 hours, and recorded on the 

 daily drilling report. If water is recovered from formation tests, a salinity 

 determination should be made and a properly marked sample retained for 

 possible subsequent analysis. Salinity tests should also be made on core 

 samples of sands. 



