Proven
Success: Conoco’s Magnolia #3
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An application of fit-for-purpose
extended reach drilling techniques yielded 30%
performance improvement on a challenging high
angle directional well. |
In less than two days per 1,000
feet below the mud line, Conoco Phillips successfully
drilled appraisal well Number 3 on its deepwater Magnolia
discovery using specially designed extended reach
drilling practices from K&M Technology Group.
The better-than-expected performance surpassed the
2.4-day estimation for drilling and casing, resulting
in a 30 percent performance improvement and approximately
$4.7 million savings based on previous appraisal drilling
for Conoco’s multi-well program.
The 1.83-day record was reached
in 4,674 feet of water, drilling nearly a 60-degree
angle to total depth of 24,200 feet (measured depth)
and 19,253 feet true vertical depth. The development
proved the commercial value of the Magnolia field,
with potential reserves estimating at more than 150
million gross barrels of oil equivalent (BOE).
Directional wells in deep water
are recognized as one of the more challenging drilling
environments, particularly with the soft shale typically
found in the Gulf of Mexico. High angle directional
wells such as the Magnolia Number 3 are even more
difficult to drill.
To support Conoco’s program,
the professionals of K&M Technology Group, recognized
for their expertise in extended reach drilling and
complex well design, engineered and designed drilling
practices purposely suited for high angle wellbores.
To ensure successful implementation, the group of
engineering experts provided detailed training to
all field and office personnel, often challenging
conventional thinking associated with traditional
stuck pipe instruction and experience.
With a deeper understanding for
drilling high angle wells, the drilling team developed
a detailed well plan using a conscious and disciplined
approach, which K&M Technology has mastered over
the past 15 years. Some of the techniques for this
particular project included hole cleaning, directional
drilling and tripping practices uncommon to most ERD
projects. These practices and planning techniques
have been integral to the step-change in performance.
Considering the success of the appraisal directional
wells, Conoco and K&M Technology have designed
a more aggressive development plan for the production
wells. The expected savings for the Magnolia development
could be significant if the initial performance is
repeated.
Development of the Magnolia field
is expected to commence as early as the end of 2002.
It is believed that practices similar to those used
in developing the Magnolia discovery can lead to step-improvement
in drilling performance on other deepwater projects.
ATP Case Study
A Gulf of Mexico well was in trouble. Working off a very small platform and a fit–for-purpose drilling rig, a 80 degree+ well was drilling under a ship channel. A 11 7 / 8 ” long string had been run and was set several thousand feet off bottom. Drilling continued and cleaning the large amount of rathole became a problem. The operator had a choice of cementing back to the shoe and sidetracking or running casing. The well looked impossible to case.
K&M designed a 9 5 / 8 ” liner that would be floated and rotated.
That liner was run off the boat and successfully floated and rotated to bottom. Rotation was necessary due the predicted buckling problem.
The 9 5 / 8 ” liner was successfully floated and rotated to bottom with near impossible hole conditions. The larger rat hole (14 1 / 2 ”+) was difficult to work thru because of the excessive amounts of gumbo.
The well is completed and producing.
ATP supervisor comments were: “I didn't think anyone could get casing in that well. Thank You K&M!!”
ExxonMobil Ringhorne Case Study
Initially became involved to critique previous feasibility study and preliminary well designs. K&M review found the initial designs were destined for failure, due to inability to run casing to TD and ECD management problems. This project turned out to be very complex with the well designs truly an example of "systems design".
In the end K&M designed three types of wells depending upon the reach and reservoir being targeted.
The first of the key wells (C18) was drilled and completed in 2003. This involved floated 9 5 / 8 " liner, with complex drillstring design, fluid rheologies and practices designed for minimizing ECD's.
Esso Norway are currently progressing this project using K&M well planning software.
ExxonMobil Sakhalin Island - Chayvo Case Study
With the assistance of detailed engineering planning and operational support from K&M engineers, ExxonMobil were able to successfully drill several world-class ERD wells in a remote location, with little relevant offset data, no learning curve, and a new-build rig.
K&M has been involved in the engineering design of the ExxonMobil Sakhalin Island development project for the last 7-8 years. K&M's involvement in the planning phase for the Chayvo development wells has included the following:
- Early well feasibility and rig design studies (scoping stage)
- Preliminary Offset Well Review and Mechanical Feasibility Study
- Site visits to collect offset data from Russian ERD wells
- Preliminary Well Design to further define rig and equipment specification
- Detailed Well Design (directional strategy and tool specification, T&D analysis, hydraulics and hole cleaning, casing installation, operational guidelines etc).
- ERD training for office based engineering staff
- Preparation of Detailed Drilling Programs for the first two ERD wells
In addition, K&M has also been involved in the design of other areas of the Sakhalin project, including the Odoptu development, and offshore Orlan development. Again, the scope of this involvement has included engineering of the ERD well designs and rig specifications.
With a commitment to extensive upfront engineering as detailed above, the first two ERD wells were drilled successfully, with no significant drilling problems encountered in either well and the wells drilled in the budgeted time. The first ERD well, the Chayvo Z6 was drilled to a measured depth of 9375m MD (8420m stepout), making it the 7 th longest well in the world. The second well, the Chayvo Z4, was drilled to a measured depth of 10183m MD (9246m stepout), making it the 4 th longest well in the world. K&M's involvement during the operational phase of these wells included the following:
- ERD training for onsite operations personnel.
- Onsite K&M advisor present throughout the first two wells. Roles included data collection, interpretation, and guidance related to ERD drilling and casing running practices.
- Office based engineering support with roles including daily surveillance, data capture, forward planning on the current well, and optimization for future ERD well designs.
Statoil Gulfaks B-42 E/T@ Case Study
Sidetracking a 13 3 / 8 “ x 9 5 / 8 “ wellbore, a pack off situation developed in the longest 8 1 / 2 ” ERD section attempted in the field. As circulation and rotation reached critical levels activating the viscous coupling, packing off intensified. Drilling near parallel to the formation layers resulted with an enlarged well bore. That enlarged well bore became a depository for cutting and pack off frequently increased.
After drilling stringers of coal, packing off and lost circulating became worse. With successive pack offs, the wellbore irretrievably enlarged.
Ultimately, the original well bore was squeezed at the shoe and the well restarted. The same ‘symptoms' occurred on the second penetration and a down hole stalemate resulted. Drilling parameters brought the cutting out of the caverns. When those cuttings came out, they packed off in the in gauge section of the well, fracturing the formation and generating a larger cavern. Those cavities filled with more cutting, which subsequently pack off again and again.
K&M diagnosed the well bore stability problem and designed a 7” liner to save the well. This liner was run and purged with nitrogen for down hole safety concerns and floated in. As buckling began (as predicted) the liner was rotated thru the unstable lower hole sections to total depth.
The 7” liner was successfully floated and rotated to bottom with near impossibly hole conditions. The well has been completed and production is better than expected.
Statoil's comments are “I imagine that the success of floating in the liner will have a great value for Statoil in the years to come, stretching the limits for well design. I have great respect for the work K&M did, recognizing that it would not have been possible without you.”
