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l3v1ck
Well after months of pressure from friends I’ve finally joined facebook. I was resisting a bit as I don’t like the idea that strangers (friends of friends) can post stuff on your profile, but I’ve been through and tweaked as many security settings as I can find.
My Facebook profile isn’t for every Tom, Dick and Harry, but if any of the regulars on these forums want in, send me a PM.
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l3v1ck
I should just point out for those who are used to my dinosaur avatar on the Custom PC forums, it simply wasn’t big enough to use as an avatar on these blogs. Instead I’ve used a photo of a band from Doncaster called Stafford Galli. The photo is eight or nine years old now and was taken when they played The Dome in Doncaster. They split up a few years later, but I’ve have heard a rumour that they’ve got back together, albeit with an almost totally different line up. Their albums are:
1st - Phrygian Knights
2nd - Stafford Galli
3rd - Bring It Back Home
Back then I ran their website, though it was fairly basic as my web skills aren’t that great. (it doesn’t exist anymore). On their last ever gig together the band signed some of my album covers, which was nice of them.
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Loading ...My work for the next three years
l3v1ck
In oil rig news today:
I’ve just been assigned permanently to the Sedco 712 (see below; it’s the one on the right). A bit of an old rust bucket, but it has two man cabins and internet access, so I can’t complain. It’ll be nice not to shift from rig to rig all the time.
Although this rig was built in 1983, the design (711 class) is just a slightly updated version (2 man on-suite cabins rather than 4 man cabins with communal bogs and showers) of a design (700 class) first used in the early 1970’s (The Sedco 700 was launched in 1973). There’s nothing modern about this rig at all.
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Loading ...The use of PC’s offshore
l3v1ck
Introduction
The are some tasks in life where computer equipment becomes more and more complicated year after year, but with other tasks the use of PC’s has replaced expensive specifically built hardware and software. Both of these statements are true offshore on the rigs that drill for oil in the North Sea. While the rigs themselves have become more and more complex and technical, the means by which data is acquired and stored has become more and more mainstream. This blog entry is going to cover the use of PC’s and networks in the field of SDL (Surface Data Logging).
Overview
Surface data logging is a service provided to oil companies by 3rd party companies. It’s the recording of time based and depth based data recorded from a variety of sensors at the surface of the oil well (ie, on the rig itself). In recent years it has become common practice to have sensors down the well as part of the drill string. This is known as M/LWD (Measurement/Logging while drilling). This data is often stored on a combined database with the SDL data. SDL data includes the following type of measurements: lengths, weights, volumes, flow rates, pressures, fluid densities, temperatures and (most importantly) gas levels.
The introduction of PC’s in SDL units.
Before PC’s became common and relatively cheap in the mid 90’s, logging units used banks of Chessel Charts to record real time data. This data was only recorded in graphical form, no database of numbers was created. All the depth base logs were drawn by hand. This system was replaced by highly specialised computer systems where each function was performed by a dedicated add in card. The main bonus over the charts system was that the actual numerical data could be stored as a database. The problem with this system was that there was not enough storage capacity to keep all the data from one well on one system. The data had to be backed up to removable media and then wiped off the main system several times a day. In the mid 90’s these specialised systems were phased out in favour of PC’s which processed the data using software rather than dedicated hardware. This made recording the data much more cost effective.
How the PC’s are used today.
Today most SDL sensors work on a range of 4-20mA. These signals are processed by a device called a Datascan which converts all the separate signals into 2-10v signals that are passed down one RS232 (serial) cable into the PC. The PC then has dedicated software that converts these signals into numerical values and then stores them in a database. By the early 21st century improved networking bandwidth means that this data was no longer confined to the logging unit. On most rigs today there are often several remote screens in key areas on the rig, these are controlled remotely over the network using VNC as most people who need to access the data aren’t familiar with the software. Some oil companies also pay extra for the data to be transmitted via satellite to their offices, though the amount of data that can be sent is sometimes limited by the amount of bandwidth available.
SDL PC design.
You might think that a PC is a PC, and as long as it is capable of running the software that’s required then there should be a problem. The selection of components is slightly more complex than that. In each unit there are two database PC’s, one main PC and one backup. Although these PC’s can have different components, that make it much slower to switch from the main PC to this backup if the PC fails. This might not sound like a big deal but most oil companies stop drilling if they can’t record gas levels. Given that the rent for a mobile offshore drilling rig can be several hundred thousand pounds a day, time is a big issue. If the PC’s have the same components, all the setting can be copied to the backup PC and it can be up and running very quickly. Non standard components that are in these PC’s are a second network card and a four port RS232 card. Other design considerations include cooling and noise levels. In a modern SDL/MWD combo unit there are up to five PC’s, ten TFT’s and a whole host of other electrical components that produce heat. In the summer (even with air con) it can reach over thirty degrees in the unit. Because of this cool running components are often selected along with large HSF’s if possible. No (Halliburton) unit ever had any PC’s using Pentium 4 CPU’s. Water cooling is not used because of it’s potential problems. Sound levels are not as important as cooling, but they are still considered. Logging unit do have have a large amount of background noise, this mainly comes from the large fans that pressurise the unit and from the air con unit. Although it’s very hard to pick out PC fan noise over these (unless you’re sat right next to them), the overall noise levels needs to be kept as low as possible. Once the noise reaches a certain limit ear plugs must be worn which it not a desirable thing in an SDL unit. Data storage is another consideration. Modern hard drives are easily capable of storing all the data from a well, however backups are very important. Up to 2004 MO drives were used due to their reliability, but they were replaced by CD and DVD writers due to their larger capacity. Having experienced two hard drive failures in three days myself, I can’t point out strongly enough the need to make regular backups of any work/data you have.