820 Subsurface Geologic Methods 



The maximum interval during which the hole should he exposed to drilling 

 fluid prior to electric logging should be kept under careful consideration, tak- 

 ing into account all known factors which will affect logging results, such as 

 lithology and mud type and quality. 



Gas Detector- — A gas detector should be used to log gas indications. 



Dipmeter Surveys — Dipmeter surveys should be used wherever practicable. 

 Coring should be reduced to whatever extent dipmeter surveys can be safely 

 relied upon to substitute for structural-control data otherwise obtainable only 

 from cores. 



Penetration. Logging — Penetration rates must be accurately logged. A 

 mechanical device which has proved satisfactory for this purpose by field use 

 should be utilized, the log from which should be checked against drillers' 

 observations. 



Radioactive Logs — Radioactive logs should be run opposite all carbonate 

 sections. Use of these methods opposite sand and shale sections should depend 

 upon estimated value of resulting information. 



Caliper Logging — Caliper logging should be utilized wherever available, 

 and when prospects of useful resulting information are estimated to justify costs 

 of the service. 



Oil and Gas Samples 



Where newly discovered oil- or gas-bearing measures are tested, either by 

 means of a formation test or a conventional production test, representative 

 samples of the oil and gas should be collected in suitable containers so that 

 they may be shipped to the United States for analysis, if the local management 

 deems the productive possibilities to be of sufficient magnitude to justify this 

 expense. 



Facilities for determination of gravity of oil samples should be available 

 at the well, and determination of gravity should be made on all samples 

 immediately upon recovery of these. Observation of the general character of 

 oil and gas should also be made immediately upon recovery from tests, par- 

 ticularly for presence of sulphur. 



An example of the form used in recording data from a wildcat well, 

 as followed by the Richmond Exploration Company, is given on page 821. 

 The use of the form is explained below: 



General 



Purpose — The purpose of "Exploratory Well Summary" is to provide a 

 routine channel for a concise summary, arbitrarily limited to one page, of 

 the most widely used geologic and related well information for the use of all 

 persons properly concerned. 



Preparation Schedule — The form should be completed for each significant 

 exploratory well, whether active, completed, or abandoned. It should be revised 

 for any given well whenever new or better information becomes available for 

 such well. 



Uniformity — Uniformity of usage adhering to the following explanation 

 must be maintained in order to assure continued clear understanding by all 

 readers of data presented. Suggestions for major changes in usage of the form 

 are in order at any time, but these must be agreed on with the head office 

 before implementation. 



