Yeah, I know this is a piece of very specific domain knowledge, and probably if you are not involved with the Oil & Gas industry, it’s not gonna make any sense for you. However, it’s interesting to know that Oil & Gas operations have a very large mass of data of all kind, transmitted in real time, to make it possible to monitor the well construction process and mainly to mitigate the risks of failures, that sometimes cause fatal accidents or huge damages to the environment …
In this article, I will provide a little understanding of the Wits protocol. There are other transmission protocols, like WitsML that is newer, more powerful in some ways, but much more complex and dependent on good infrastructure. WitsML might be subject of other posts in the future, but keep in mind that Wits and WitsML are totally different protocols for the same purpose.
Wits
The WELLSITE INFORMATION TRANSFER SPECIFICATION (WITS) is a communications format used for the transfer of a wide variety of wellsite data from one computer system to another. It is a recommended format by which Operating and Service companies involved in the Exploration and Production areas of the Petroleum Industry may exchange data in either an online or batch transfer mode.
In other terms, Wits (Wellsite Information Transfer Specification) is a specification used in the Oil & Gas industry to provide real-time data transmission. Its structure is quite simple: items within records within blocks; transmission over raw TCP socket or Serial.
Simply, it works based on an agreement between transmitter and receptor to consider record X item Y to be specific data in a specific unit.
Blocks are delimited by the && and !! lines and always refer to a single record. Records are identified by a numeric string containing the 1st and 2nd characters of the data line; items are identified by the numeric string containing the 3rd and 4th characters, and the data itself is identified by the rest of the line.
{% highlight text %} && 01082319.024 01103152.102 011221.31 !! {% endhighlight %}
Considering the example above, we have one block, with 3 data lines, in which the line 01082319.024 refers to:
- Record:
01 - Item:
08 - Value:
2319.024
Both sides of the transmission need to be aligned about what record 01 item 08 means. Suppose, for example, it’s the Bit Depth (measured) in meters. If both sides are aware of it, the transmission will be just fine. However, if there is a misunderstanding of one side, expecting Bit Depth in feet, the data will make no sense any longer.
All the mapping needs to be known and well aligned between both sides, so as to prevent these kinds of mistakes. And that’s what turns Wits to be a little weak in terms of consistency but in other hands very efficient in terms of flexibility.
Consistency and Flexibility
Time is money! The Oil & Gas operations are still very expensive, and operators push the service companies to be very optimized… One of the results of this pressure is seen in the lack of time and effort to make data transmission to be correct from the beginning. And, of course, first thing’s first. Making sure the rig doesn’t have a risky scenario is uncomparable more important than making transmission aligned.
In the end, it causes the transmission to be the last concern of the companies at the rigs, and this is where the consistency not enforced by the protocol appears.
However, being simple as 1 2 3 makes configuration of Wits a simple setup, as well as makes it easier to create new software to transmit it. Having this fact, associated with the protocol’s maturity, the compatibility of the protocol with the industry is huge.
Versions
There are some different versions of Wits but as per my experience, the most widely used are Level 0 and Level 1. A big difference between these two is that Level 1 has twenty-five predefined records and items identified, covering drilling, geology, directional work, MWD, cementing and testing. Having these pre-defined records makes a little easier to maintain an agreement between the sides.