Having written for a while now about various national data repositories as an outsider, I could hardly refuse an invitation to attend a meeting of the Common Data Access Ltd. (CDA) board of directors. So I dusted off my old boardroom Armani and hailed a cab. The invitation was a no strings attached affair, and the CDA presented their activity in a very open way, with a free discussion of both the successes and the inevitable teething troubles associated with such an such ambitious project. The initial business driver behind CDA was the multiplicity of paper and tape copies of well logs generated by partnerships and trades. Dave Overton, CDA's chairman, has estimated the number of tapes associated with modern well as around 10 with an additional 40 or so sepias. This is just for starters, and in the UK North Sea there are about 300 wells drilled per year at the present.
Immediately after a well has been drilled, copies of all this data are made for partners, and over the next five years, before the well is made public, further copies are made each time the well is traded. An irony of all this is that frequently, individual oil companies may share the same storage contractor who dutifully stores and indexes all these multiple tapes and logs in boxes in the same warehouse. Clearly a situation crying out for a cooperative solution. Tacked on to these practical objectives were a few further looking business drivers, in the first (well log) phase this was the provision of on line access to archived data, and also the provision of "added value data" in the form of edited, depth matched quality controlled curves. The first two data types are controlled by the CDA consortium, while the added value data is supplied by third party vendors such as PI/Erico and Robertson. The first consortium meeting was hosted by Amoco in 1993 and was an immediate success, with great interest from the industry. The Common Data Access Initiative was founded, headed by Amerada Hess and the decision was taken to form a joint company, Common Data Access Ltd. to handle the first phase of the project.
The UK Department of Trade and Industry (DTI) has been a sponsor of the project from the outset and also an enthusiastic partner. Operations began in March 1996 and the CDA archive was initially populated with wells donated from Shell, BP and Conoco. The first surprise was that although these datasets were large, they was also a lot of overlap between them, so that there was a shortfall of around 3000 wells from the overall target of the 6500 wells drilled to date on the UKCS. Other problems such as well naming conventions, or rather the lack of them, and a poor historical record of entitlements threw more spanners in the works. These naming convention issues have largely been dealt with now with input from the DTI (see the other articles in this issue). When Isobel Emslie (Conoco) presented her paper "CDA, the Pain, Process and Progress" at the Stephenson conference back in September, the entitlements issue was proving rather intractable.
The onus was on member companies to supply entitlements on diskette for the wells that they owned. Members tended to rate this activity rather low in their priorities until a policy of fining recalcitrants £500 per day for late delivery was introduced by CDA. This has worked wonders, and the entitlements database is now fully up to date. Today the CDA has 32 oil company members, the two aforementioned contractors, plus the Department of Trade and Industry (DTI). QC Data manage the CDA project under a service agreement from offices in Aberdeen and on Canary Wharf (London). Their data server environment is a three tiered affair, with the archive built around GeoQuest's LogDB product. This essentially is a repository for bulk data in native format, as delivered by the members (i.e. field logs with multiple runs, ancillary curves and measurements and backup sections). The lowest level access provided to members is to an FTP buffer site, which can be pre-loaded with required data on a member's request. This currently offers access to the whole archive of some 3500 wells. The next tier in the structure consists of the online datastore. This is provided using QC Data's Information Hub. This level contains the critical entitlements index as well as a subset of the Archive data in the form of a standardized suite of well logs. These offer the users a quick route to the curves which are most likely to be used, but does not yet constitute the added value data.
This is supplied by third parties, and is also stored in the Information Hub. The third tier resides at the user's site and is made up of QC Data's Axxses product, a forms based browser allowing for look up by line name etc. or areal search by input of geographical co-ordinates. Between the two top tiers is the network, currently either modem or ISDN lines.
The current status of CDA is that all currently drilled wells are entered into the Archive in real time, i.e. at a rate of about 35 wells per month. If we just consider the initial business driver-the desire to avoid multiple paper and tape copies then CDA is already a demonstrable success. No longer do operators have the overhead of supplying multiple copies of data to partners, and trades are likewise simplified. The position regarding on-line access to historical data is not so rosy. The overlapping initial datasets means that only about 3500 of the 6500 are actually in the archive.
This leaves QC Data with two background tasks, loading the 2000 or so historical wells, and subsetting the curves from the Archive to the online Information Hub. Currently this is done in response to members' requests at a rate of around 25 wells per month. At this rate it will be some time before the ultimate goal of populating the archive with all the 6500 wells has been achieved. CDA are faced with the problem of managing their available resources to the satisfaction of their members whose needs are not all quite the same. A larger company with an established system for handling raw log data may be quite happy with an FTP link to the archive site. A smaller company, or a larger company with a different philosophy of data management may be looking for more selection at the source, and may be concerned with the relatively slow progress in populating the on-line database. In the meantime, the commercial vendors are waiting to leap into the breach with the added value data, effectively creating a third category of user who requires, and is prepared to pay a premium for, both selection and processing of data before retrieval.
CDA is very aware that the management of CDA by committee, while a fine example of inter-oil company cooperation, is proving less than optimal now that this major project is up and running. The board of directors are currently looking to appoint a third party to perform the day to day management of the operation and to improve communications with members and the outside world. CDA is a going concern today with 685 curves ordered and retrieved during December 1996, and 366 logins by members during the same period. The project is gathering steam with the capture of paper data through scanning to bitmap, and soon, there will be a tender out for the seismic phase of the project. CDA members are aware that they have a "product" which may be of considerable interest to other countries, and Stewart Robinson of the DTI is very active in promoting inter-country cooperation in National Data Repositories. No firm location has been selected for the next implementation of a CDA modelled repository, but the ideal location has been described as a new exploration area - with little or no existing infrastructure to complicate the issue. The actively explored virgin territory of the offshore Falklands has been mooted as a likely candidate.
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