Since 1966, the American Petroleum Institute has set the standards for numbering the more than three million oil and gas wells in the United States, with regulatory agencies typically being the creator of the actual numbers assigned.
This well numbering standard has not been officially updated since 1979, despite the many technology changes that have occurred.
In this standard, the API D12A Committee laid out a 10- or 12-digit number (called API number), which included the state and county code, a well identifier number within the country, and a direction sidetrack code (if applicable).
In setting this standard, it was anticipated that each well/wellbore drilled in the United States could be recognized uniquely with a number that would not change – and that the many different well data types (logs, cores, directional surveys, tops, production, etc.) could be successfully linked or integrated in a digital mode.
The problem is this: The way the API number is used by different groups has evolved since the late 1970s, and the variability in the number assignment is a key issue.
During that time three efforts were organized to close that gap.
The latest is happening now.
AAPG member James Stolle, business development manager for TGS Geological Products, Houston, is among those spearheading th/e new numbering schema, which he says is long overdue.
The initiative is coming from the Professional Petroleum Data Management Association(PPDM), a member-driven, international organization dedicated to providing data management standards for the petroleum industry.
PPDM’s work “supports the growing data management needs of a diverse worldwide membership” that includes oil and gas companies of all sizes, national and international oil companies, software and data vendors and oilfield service companies.
Stolle said the API number is still following numbering practices and procedures from the 1970s onshore and it affects the efforts of all trying to do interpretation efforts – particularly in areas with lots of historic well data.
“I personally believe that was a bit too restrictive in what received an API number,” he said. “Virtually every well drilled, regardless of its purposes, has subsurface information that can be utilized by those doing interpretation. Where the well/wellbore does not get ‘officially’ recognized with at least a 12 character API number, the presence of the wellbore, its well path and all the associated well data is essentially lost in today’s computer driven efforts.”
To put it another way, he says, “The API number is like the Social Security Number to Americans – it is the one common way across the U.S. of identifying uniquely the wells drilled in the U.S. and the various states. Revenues and royalties are tracked using the API number.”
The number also is used by those looking for new fields and exploiting older discovered fields, and as the primary way of integrating all the digital types of well information
“When I started in the industry in the mid-1970s, data integration was a manual effort,” Stolle said. “It was slow, manual and, because of the slowness, less subject to linking the different well data types incorrectly.”
Granted, the “old” system worked. But like a city that runs out of exchanges for its one area code, the demand was putting strains on the system.
“Jump forward 20-plus years, and the digital data with our collection of G&G interpretation applications can be linked together data on thousands of wells in seconds,” he said. “That linkage assumes that all the different sources of well data are uniform in the reference number associated with the data (the API number).”
And that’s the key.
“Therein is the fundamental problem and the need today,” he said. “How the API number is implemented has varied between regulatory agencies, operators and vendors and has evolved over the last 20-plus years. Data gets incorrectly linked because of minor differences in the API number assigned by the different data.”
Other problems, too, were evident.
“Another area of concern to me,” Stolle said, “is that all drilled wellbores, even those drilled for oil and gas purposes, do not get officially designated with an API number, which includes 12 characters or more. From the research that I have been involved with over the years, there are at least 10-20 percent more well bores drilled (onshore and offshore) than have been ‘officially’ recognized with API_12 length numbers.”
He cites an “absurd” example of a well in Cameron Parish, Louisiana, which shows a 5,900-foot producing well that became the well/wellbore of record and received the “official” API number – it happen to be the sidetrack 1. The original hole that went to 10,750 feet and logged to TD, but was not assigned an API_12 – meaning, he said, it was forgotten and essentially lost to the industry.
“A few years back I had the experience of finding a big, black mark on my credit report and a serious charge,” he said. “As it ended up, a minor mistake in a social security number from another person in another state who was passing bad checks was linked to my credit data through the social security number.
“Now consider how we link well data with the API number … very much like the social security number,” he said. “And any minor differences will cause data to be linked incorrectly.”
Stolle says it is not a rare problem, either.
“It is too common, and it can cause very expensive mistakes in interpretation. This is ‘Why the need?’”
Try, Try Again
That need, he says, has been around for 20 years.
“In the early 1990s, efforts to renumber the system were about 90 percent complete,” Stolle recalled. “Then the then-leader of the D12A committee passed away unexpectedly, and there was confusion as to the whereabouts of the unpublished manuscript.”
The program languished for 10 years, but around the year 2000 the API was approached again on the idea of updating the D12A standard.
There were several responses, Stolle recalled, including someone from the API saying, “We do not perceive the API number as much of a problem, as none of the board members are complaining, so it must not be much of a problem.’”
Nevertheless, he was told if he wanted to pursue it, API would publish his findings.
There was a caveat: no funding.
Stolle said he demurred, because, “I did not have the time, being self-employed, to devote six months to the rewrite.”
The project died again.
Then, in 2008, while under the employ of P2ES, Stolle found the time and re-approached API on updating the standard.
There were challenges: Once he was able to determine who was in charge of the original project – not an easy task – he was told API might consider transferring the standard to another organization.
“A number of potential alternatives to taking over the standard were reviewed,” he said, “and in the end I was impressed most with PPDM’s approach, thoughtfulness and recognition of the effort they were going to have to perform.”
But PPDM, according to Stolle, had to address:
♦Addressing all the wells.
"What and how the standard was written to be used 30 years ago has evolved,” he said, “and our data management practices today require some different approaches.”
♦Wells had to be assigned numbers from one source and not, as was the case, from various regulatory agencies, operators and vendors.
"Without an absolute standard that all users of well data can ‘sync’ to, there will always be differences in what API numbers get assigned and used."
To succeed, he and his team – which includes AAPG members Steve Cooper, PPDM project coordinator, and Bruce Smith, vice president at IHS in Denver – worked with the Interstate Oil and Gas Compact Commission (IOGCC) and various state regulatory groups to number new wells with at least an API_12-like number and in the manner prescribed by the current and PPDM’s new version of the D12A.
Paying the Price
Stolle wants to make clear that a guiding principle is to avoid changing an API number once assigned.
“The unique identity (API Number) must be fixed and unchangeable throughout time,” he said. “Thus for the U.S., I do not see a new well identity number being assigned to existing wells that already have API numbers.”
Cases where incorrectly assigned API numbers are noted, however, would be better handled with a change.
He says that clarification on how wells are assigned numbers (and what designates a well) will benefit all.
“There have been many drilling technology improvements over the last 30 years with horizontal drilling, for one,” he said. “Today, with I believe over 60 percent of our new wells in the U.S. as deviated or horizontal, we need to recognize any and every well and wellbore and their well paths and be able to number them consistently.”
Successful completion of the project will require industry funding to support the participation of some key experts, communication, technical and administrative costs.
“At this time, we estimate that the total cost of the project will be approximately $250,000 (US). The PPDM Association is presently soliciting this sponsorship, so that the project can be launched and completed in a timely and efficient manner.”
To date, sponsors include Anadarko, BP, Chesapeake Energy, Chevron, ConocoPhillips, ExxonMobil, geoLogic, Hess, IHS, Marathon and TGS.
According to the PPDM website, the new standards have been adopted – inconsistently – by most of the United States, but not by Canada or Mexico.
“Our API effort will not be free,” Stolle said, “but it will work and cause the data management and interpretation efforts for the whole industry to be far more comfortable and beneficial than they currently are.”