AT ADCO: "Drilling the Limit™ is a unique process and has helped us to change the way we approach our drilling and to develop more sophisticated drilling priorities," says Abdul Munim Al-Kindy, Deputy General Manager, Operations, Abu Dhabi Company for Onshore Oil Operations (ADCO).
"Some time ago at ADCO, we decided to see how we could improve our drilling performance and we approached our shareholders to see if they had any processes which could help us.
One of those shareholders was Shell [with a 9.5 percent shareholding in ADCO], and they had a system called Drilling the Limit™, which we decided to pursue.
"In the beginning, there were some skeptics, but the results of Drilling the Limit™ have spoken for themselves, and we are now under pressure from all our shareholders to expand the process into all our operations.
"During our first experience with Drilling the Limit™, we obtained a 45 per cent improvement in the time it took to drill a well and this, of course, also represented enormous cost savings.
"This success has continued. We started planning for Drilling the Limit™ in 1999, and by the end of 2000 we had saved more than 200 drilling days and in excess of US $6 million.
The greatest improvement we have seen is in the drilling of vertical oil wells, where we have cut drilling time from 30 days to less than 15, generating a saving in time of 51 per cent and a cost saving of 23 percent.
"In ADCO, we have nine drilling rigs and previously we have been able to drill eight wells a year with each rig. Now that we have introduced Drilling the Limit™ we will be able to drill three more wells a year with each rig, which is a massive increase of 27 wells throughout the year.
"Shell have been very supportive by providing us with experts from Shell Technology E&P to implement the process. They have also provided training for our staff.
"We hope that we can maintain the momentum that we have generated so far, and I have no doubt that Drilling the Limit™ will be used in other ADNOC [Abu Dhabi National Oil Company] operating units.
Indeed, ADNOC has backed this initiative and has made it all possible. "So, all in all, we are very happy with Drilling the Limit™ and with Shell for their help and technology transfer.
We are looking forward to the next phase and to implementing Drilling the Limit™ throughout all our drilling operations.
We are now in the process of identifying additional resources required to carry this out and are examining the impact that Drilling the Limit™ will have on our overall business plan," he concludes.
Expandable Tubular Technology:"Expandable Tubular Technology was first developed by Shell researchers for use in the oil and gas industry in the late 1980s," says Roger van Noort, STEP's Implementation Engineer for the technology.
Roger is currently working for Petroleum Development Oman (a company that is 60 percent owned by the Government, in which Shell, with a shareholding of 34 percent, is one of three foreign shareholders.
"To understand what this technology means to the well construction industry, you have to understand how a well is drilled.
To construct a well, you first drill a hole of a certain diameter to an acceptable depth, say 500 meters. You line this hole with steel piping, called casing.
Once this is done, you then drill through the casing, which means that the next part of the hole that you drill is of a smaller diameter than the first.
Once the second length of the well has been drilled, this again has to be lined, but with a smaller diameter casing as it has to pass through the first section of the well.
This continues, with the diameter of the well reducing as it gets deeper until the oil or gas reservoir is reached.
Normally, we start drilling with something like a 26-inch drill bit and can end up with a hole as small as six inches.
"So, apart from the fact that there are limits to the depths to which a well can be drilled as access gets narrower, the final gauge of the well casing may be narrower than required when the oil or gas reservoir is finally reached."
He goes on to explain, "When a well is drilled it is not just depth that causes problems, but the various geological formations which may be encountered during drilling, such as a water table, unstable clay and shale formations, salt deposits and strata containing high or low pressure fluids.
At the well's penetration of each of these formations, an additional casing may have to be set to permit drilling to continue safely, and this can reduce the diameter of the well earlier than desired - and lead to a situation where the well could run out of 'hole size' and the reservoir cannot be reached.
"Where Expandable Tubular Technology comes into its own is that it can enable well engineers to drill slimmer wells, which will in the future lead to mono-diameter wells becoming a possibility.
In terms of well engineering this has tremendous advantages. It works by drawing a cone-shaped steel mandrel through a length of casing of a certain diameter, which has already been inserted into a well.
The drawing of the mandrel through the casing down the well expands the diameter of the casing. Because you can expand the diameter of a length of casing down hole in the well, it is possible to insert a length of casing of the same diameter as the expanded casing, and then expand that.
This exercise is repeatable time and again, which means that depth becomes almost unlimited. "Furthermore, in oil bearing reservoirs we often find water and oil together.
Sometimes the water leaks into the oil-producing layers through fractures.
Another application of Expandable Tubular Technology could be to expand casing across fractured formations down the well to prevent water entering the well bore.
This would be a major technological advance for PDO as most of its reservoirs in the northern fields have this problem.
"All of this is very interesting for PDO.
In the long term, it will allow us to drill a mono- diameter well, a goal which we hope to achieve in 2003, and we will be able to reach oil reserves which have hitherto been uneconomical to drill.
"With mono-diameter wells, we expect the costs of drilling a well to be significantly reduced in PDO. These savings will be achieved because less rock will have to be removed from the hole, we will be able to use only a single-sized bit instead of several different-sized bits, the casing will be of a single size and narrower than currently used, the drilling rigs can be smaller as they will not be required to lift so much weight, and less steel and cement will be used to develop a well.
"It's a major step forward in well construction technology," says Roger.
...at PDO
"What horizontal wells did for PDO over the last few years, I believe that Expandable Tubular Technology will do for us in the next few years," says Saif Al-Hinai, Director of PDO's Technical Support Directorate.
"Horizontal well technology has increased our production and lowered our production costs by minimizing the number of wells that we would have had to drill had we been drilling vertical wells.
The same thing will happen with Expandable Tubular Technology, and we will be able to develop fields which we could not have developed before.
"Some of our existing wells produce water, and this technology will allow us to effectively shut off those water zones so we can produce more oil.
In new wells, it will be cheaper, in terms of hardware and consumables, in the rigs themselves and in all the materials we use.
"At the moment, we are drilling and maintaining over 2,500 active wells and this technology gives us the opportunity to achieve more cost-effective, quality well delivery.
"We are proud to be one of the companies conducting trials with this innovative process, and we look forward to a satisfactory transfer of this technology to PDO staff.
"We believe new technology in general will help us to attain our ultimate aspiration at PDO of producing one million barrels of crude oil per day by the year 2005, from the 850,000 bpd which we are producing today," he concludes.
Source: Shell in the Middle East.com
© 2001 Mena Report (www.menareport.com)
