Two world records for completions have been achieved - one in a horizontal well, and one in an extended-reach well.

Halliburton Energy Services recently set a world record with the successful completion of the longest deepwater horizontal gravel pack, placing 75,000 lb of gravel for an operator offshore Brazil. The horizontal gravel pack was completed in a 2,730-ft (832-m) open-hole section in 2,621 ft (799 m) of water. Despite the long slant section (6,562 ft at 60°) and open-hole length, installation of the sand- control completion was smooth, never reaching more than 10,000 lb of drag.
"Increasing net reserves through extended-reach horizontal wells can present many challenges to operators in deep water," said Jody Powers, president of Halliburton Energy Services. "The successful completion in this long horizontal section was due to collaborative job planning and execution between Halliburton and the operator. Matching computer simulation, using HzGPSim software, to actual job design was instrumental in the successful execution of the gravel-pack placement."
A strikingly consistent model
The HzGPSim program is designed to predict and model horizontal gravel packing in open holes and cased-hole sections. Based on equations for transport of particulates in horizontal pipes published by Oroskar and Turian in 19801, and expanded by Shah and Lord in 19892, HzGPSim models the alpha and beta wave mechanism for horizontal gravel packing. The program calculates:
• required injection and return rates;
• expected bottomhole treating pressures;
• heights of alpha and beta waves;
• predicted time for the end of alpha and beta waves; and
• minimum rate below which a premature screen-out will occur.
Nick Gardiner, senior global account leader, and David Lord, a senior research engineer specializing in rheology at Halliburton's Duncan facility, wrote the program in 1995. "A great deal of testing was conducted at the Duncan test facility to measure the effect of screen assembly geometry on fluid friction and how it partitioned fluid flow between the different pathways it could take," said Harvey Fitzpatrick, global sand-control product champion at Halliburton. Once the model was calibrated to match the theory and flow tests, it was taken to a deepwater offshore field and calibrated in the actual well.
"First you have to calibrate the friction factors through the workstring above the gravel pack," Fitzpatrick said. "The second step is to calibrate friction factors through the actual flow path that the gravel will take (Figure 1).
"Then you have to measure the returns to see how much fluid leaks off into the formation." After the three-step calibration procedure is complete, the HzGPSim model is ready to be used for the actual completion job.
The first time the program was used for a deepwater Gulf of Mexico operator, the simulated pressures matched the actual pressures observed surprisingly well. "They were close enough that I can confidently say they nearly overlaid," Fitzpatrick said. "HzGPSim predicted the end of the alpha wave and the beginning of the beta wave very closely, and if the height of the alpha wave is kept in the optimal region, you have the best chance of getting a complete gravel pack."
Fitzpatrick said using HzGPSim is standard procedure on all horizontal wells being gravel-packed, including some in Brunei and the world's longest horizontal gravel pack in Brazil. "I'm very impressed with what they've done (in Brazil)," he said. "This program really has worked. It has helped us put a lot of good gravel packs in place."
Halliburton is beta-testing a new version of the software called Wave, which not only simulates Newtonian fluids like brines but also viscoelastic gels.
Record-setting components
The record-setting horizontal gravel pack in Brazil used Halliburton's Versa-Trieve packer technology, as well as the company's multiposition weight-down tool with pressure maintenance assembly and Poroplus sand-control screens from Purolator Facet Inc. The proprietary pressure maintenance assembly provided a continuous flow path through the packer assembly to maintain a constant hydrostatic pressure on the wellbore while running the completion, which controlled the integrity of the borehole.
Spiral centralizers were used to reduce drag during installation and lift the long horizontal screen section off the low side of the hole, thus enabling uniform placement of the gravel pack over the entire interval. After the gravel packing was completed, the lower end screen section was isolated by a proprietary plug assembly, which prevents sand production from this part of the screen assembly, which is at the highest risk of damage during installation and gravel-packing.
"Halliburton's planning and successful execution of the horizontal gravel pack has paved the way for future completions in longer horizontal wells," said Roberto Muñoz, Halliburton's division vice president in Brazil. "This technological achievement demonstrated the ability to increase long-term production reliability and net reserves through the uniform placement of a highly permeable sand filter around a mechanical mesh filter over a long horizontal section."
Halliburton recently developed a new type of screen system called CAPS, which stands for Concentric Annular Packing System. This new system was designed especially for pay zones where the permeability is not the same over the entire interval. Fitzpatrick said his team of completion specialists is looking for an operator who has such a well and is willing to be a pioneer for the first field test.
Nonfloated casing record
In the North Atlantic Ocean on the Grand Banks off the coast of St. John's, Newfoundland, icebergs may be seen floating by, but not well casing. The crew of the Hibernia M-71 rig landed 23,095 ft (7,044 m) of casing in the B-16-26 well June 23, and this set a world record for directional or extended-reach wells. Other extended-reach wells like Wytch Farm in the United Kingdom may have set a longer string of casing, but they used special running techniques like floating the casing into the well by capping the end and filling the casing tube with air.
Mike Wylie, a well construction engineer at ExxonMobil, reported that the Hibernia casing string included 1,312 ft (400 m) of 10 3/4-in. pipe and 21,783 ft (6,639 m) of 9 5/8-in. pipe, for a total weight in air of 1.13 million lb. The maximum hole angle in this extended-reach well was 85°. At press time, the well had not yet been finished, as they had 2,000 ft (610 m) more to drill. The well's measured depth is expected to be 27,066 ft (8,249 m), with a 11,570-ft (3,526-m) TVD. The water depth at Hibernia is 260 ft (80 m), and the operator, Hibernia Management and Development Co., is a consortium comprising ExxonMobil (33.125%), Chevron Canada Resources (26.875%), Petro-Canada (20%), Canada Hibernia Holding Corp. (8.5%), Murphy Oil (6.5%), and Norsk Hydro (5%).
Software for Hibernia
In 1995, RWD Technologies developed an electronic document management solution called the Hibernia Technical Document Management System (TDMS), which catalogs, searches, retrieves, assembles and distributes electronic documentation for the entire Hibernia offshore oil production platform (Figure 2).
Because Hibernia's technical documents come from many different sources, are packaged in many different formats and contain many complex interdependencies, the TDMS applies a conversion methodology to each document and publishes it through Interleaf's WorldView.
The TDMS includes:
• a full-text search capability across all documents in the system;
• graphical navigation aids to guide the user through the layers of information; and
• hyperlinked tables of contents for automatic access to linked information.
References
1. Oroskar, A.R. and R.M. Turian: "The critical velocity in pipeline flow of slurries," AIChE, Vol. 26, No. 4, pp. 550-558, 1980.
2. Shah, S.N. and Lord, D.L.: "Hydraulic Fracturing Slurry Transport in Horizontal Pipes," SPE Drilling Engineering, pp. 225-232, September 1990.

Editor's note: For more world records, watch for the annual Drilling & Production Yearbook, scheduled for publication in the March 2002 issue of Hart's E&P.