PESGB, CDA & Standards (April 1997)

Data quality deemed major issue at Petroleum Exploration Club of Great Britain (PESGB) Data Management Special Interest Group. Well naming of multi-branch wells has presented near-intractable problems to North Sea operators.

Paras Alan Smith, senior consultant to CDA, had something of a baptism of fire at the last PESGB Data Management Group meeting. The topic of the day was data quality, and Ashley Dunlop listed his pet data quality problem issues as

When is a well not a well, or well, sidetrack and re-entry naming inconsistencies.

Missing meta data such as depth datums (KB, MSL, Log, Driller, TVD etc.)

In the case of TVD data, missing information as to how the method of TVD computation

Inconsistencies in checkshot surveys

The meeting then focussed almost completely on well naming conventions, with various solutions envisaged. Opinions were expressed on the advantages and disadvantages of using various Universal Well Identifiers such as those from Petroconsultants, the American Petroleum Institute, vendors and CDA.

Unique ID required

The problems of the DTI's well naming conventions were also discussed in particular in the case of abandoned well segments which do not merit a separate DTI identifier. The use of the DTI's drilling sequence number (DTN) was mooted and Alan Smith pointed out that many of these issues were under consideration at CDA Indeed, a subsequent visit to the CDA website ( confirmed that this is well trodden ground. CDA's standards page states "The requirement is to have a unique well identifier, recognised by the DTI and understood by all CDA members, and also to allow for wells to be identified differently by individual companies." Specific requirements of the CDA standard are further described as :

To be able to identify wells uniquely prior to spud by target reference and/or slot number.

To maintain aliases

To recognise components of DTI well number

To be able to sort wells efficiently

CDA's answer to this is to adopt the DTI well registration number as "the only official well number." The rest of the CDA standards web page along with the relevant pages of the DTI's website ( read like a summary of the PESGB discussion group leading one to think that the problem is more one of communication that standards.

Smith's baptism of fire which we referred to earlier came when it emerged that CDA did not archive either deviation surveys or checkshots. This cause some howls of anguish from both G&G's who found, if not common ground, at least similar axes to grind. It is indeed hard to see how much use can be made of logging information without one or both of these additional data sets.

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