Total has been operating the Maharaja Lela Jamalulalam (MLJ) field in Brunei for the last 20 years. In 2015, we installed a third well platform to produce new, deeply buried, ultra-high pressure/high temperature (HP/HT) reservoirs. With a pressure in excess of 17,000 psi and a downhole temperature of 165°C, the MLJ3-03 well was the most challenging ever drilled. With the help of our service companies, we leveraged our HP/HT expertise to overcome these hurdles.
We’ve been dealing with extreme field conditions — a low condensate-gas ratio, ultra-high wellhead pressure and interbedded reservoirs with more than 50 different layers — since the beginning of the Maharaja Lela Jamalulalam South (ML South) campaign in 2015. Thanks to the experience gained on the Elgin field, we’ve solved many of the well architecture design challenges historically faced on HP/HT projects.
For the MLJ3-03 well, our first ultra-high-pressure development well in the country, we chose a selective perforation strategy based on effective vertical isolation. However, after considering the possibility of using an Elgin-Franklin-type two-string (10¾-inch VM110SS-11ksi thick pipe and 10-inch VM140CY-140ksi production casing) well design during the pre-project phase, we realized that another solution would be needed to ensure safe implementation. The production casing string weight as used in the U.K. was not capable of withstanding such high pressure. It also was of paramount importance to ensure zonal isolation between the water-bearing layers and the productive intervals.
Pushing the Industry's Technical Limits
We led a global team of service companies to engineer dedicated solutions that would ensure the integrity of the production column. Taking the time to listen to the various experts involved — who came from different companies and countries — and leverage their know-how, we worked closely together to develop technically challenging innovations.
- We developed and qualified a new 10½” (270.9 mm) casing diameter size compliant with our strict casing design rules. The design paradigm was very specific: withstand the extreme loads, optimize the string weight, maintain a minimum clearance similar to that of a 10-inch (258.0 mm) casing in a 12¼-inch (316 mm) hole.
- An HP/HT flexible cement system (FlexSTONE) was specially designed and rigorously qualified, ensuring zonal isolation, which is critical not only to well integrity but also to production throughout the well’s lifetime. After more than 90 tests carried out in six international cement labs, we developed a resilient formulation with optimized cement mechanical properties. Due to the reservoir pressure, a FlexSTONE cement slurry with a specific gravity of 2.48 was used, the highest density ever developed.
- On the completion side, the latest generation of premium connections was intensively tested for the production tubing, according to the most rigorous protocol applied in the industry (ISO 13679 FDIS:2011 CAL IV).
A Successful Campaign Thanks to Teamwork
The suite of technologies used to drill through the hard formations and high temperatures encountered set several records, such as the first use of a coiled tubing (CT) gun snapshot deployment system on 15,000 psi wells and the first single-run installation of a wear sleeve in a downhole safety valve (DHSV) on coiled tubing using piggyback while running perforation guns. Overall, we shortened the time needed by 35% (six wells were delivered about a year ahead of schedule) and reduced the cost by 55% versus the initial estimate. Our HSE performance was also excellent, with no lost time injuries recorded.
This performance can largely be attributed to efficient and active collaboration with our service companies and the preparation time, both of which were paramount to achieving these results. By developing a relationship based on mutual trust, we were able to build an open, no-blame culture. The partnership allowed us to find the best possible solutions to all challenges, in the best interests of the project.
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