Duties and Reports of the Subsurface Geologist 837 



separate in order to permit individual reproduction of heading 

 and log, which normally are of varying densities and require dif- 

 ferent velocity and light to reproduce. Prints of heading and log 

 are later joined together. 



.04 Log 



.041 Geological Data 



a. All geological period, formation, member, zone, and sand names 

 are drafted in accordance with the draftsman's guide. Variations 

 from the standard guide are made only when the characteristics of 

 the log are such as to require change. Only faunal zone tops will 

 be shown. Well depth and zone are shown by using inclined 

 Wrico Guide 90, Pen No. 7. 



b. Conformable formation contacts are represented by a solid line, 

 and unconformable formation contacts by a wavy line which 

 passes completely across the log. These lines do not interrupt the 

 graphic representation of cores or perforations if they are in- 

 cluded in the log. 



c. Sand tops and bottoms are represented by a solid line passing 

 from the S. P. curve through the center of the log to the normal 

 resistivity log (without interrupting the graphic representation of 



, core or perforations) . 



d. Depths of formation tops, sand tops, and base of sands are drafted 

 in vertical numbers with Wrico Lettering Guide 90, Pen No. 7. 

 Subsea depths are indicated in parenthesis opposite the well depth 

 with a minus sign opposite the depth. 



e. When the thicknesses of sand bodies permit, sand names are writ- 

 ten vertically from bottom to top on one line, unabbreviated in 

 accordance with the draftsman's guide. When necessary, the sand 

 names are abbreviated and/or written on two lines. Occasionally, 

 when necessary, sand and formation names are written hori- 

 zontally to fit within their limits. 



f. Net sand thicknesses determined by log and/or cores are drafted 

 freehand. They are slightly inclined opposite the sand body on 

 the resistivity side of the log in accordance with the draftsman's 

 guide. Net oil sand open to production may be shown in paren- 

 thesis to the right of the net-sand figure. 



g. To facilitate the addition of net oil-sand figures (or, oil sand- 

 stone) in any one sand or formation containing numerous sand 

 bodies, the sum of all net oil sands (or oil sandstones) is drafted 

 at the base of the sand, group, zone or formation on the resistivity 

 side of the log in accordance with the draftsman's guide. Whenever 

 the total net-oil sand for any sand or formation can be readily 

 determined without considerable addition, the sum is omitted. 



h. Whenever a sand, such as the Lower Lagunillas sand, is broken 

 down into zones, each zone is bracketed and the zone title is 



