ARDALIN FIELDS FLOWS DESPITE WEATHER, TERRAIN

Oct. 9, 1995
Michael W. Britton , Robert Speirs Conoco Inc. Houston Gordon Pace , Carlton T. Sikes Paragon Engineering Services Houston
Michael W. Britton, Robert Speirs
Conoco Inc.
Houston
Gordon Pace, Carlton T. Sikes
Paragon Engineering Services
Houston

Part of Polar Lights Co.s major development of the Ardalin field in Russia was a 42 mile, 12-in. coated, insulated, and jacketed pipeline of arctic grade X-65 seamless pipe. Leading off this years exclusive Pipeline Report is a detailed look at this important project. An easier way of determining a steels fracture toughness before placing an order is another article by two leading pipeline metallurgy experts. And a third article reports on a major advance in gas pipeline repair that is undergoing extensive U.S. field evaluation.

On Aug. 22, 1994, first oil was produced from the Ardalin field, north of the Arctic Circle in the Timan-Pechora basin, Russia, into the newly constructed central production facility built by Polar Lights Co. (OGJ, Sept. 5, 1994, p. 38).

This company is a joint venture between Conoco Inc., Houston, and Arkhangelskgeologia, a Russian geological enterprise operating in the Nenets Autonomous Okrug, adjacent to the White and Barents seas in northwest Russia.

Included in the project is a 42 mile, 12-in. pipeline of arctic grade X-65 seamless pipe. Coated and insulated, it is also protected by a galvanized metal jacket. Throughput capacity at maximum allowable operating pressure (MAOP) of 1,995 psig at 250 F. is 80,000 bo/d.

Although development of oil fields north of the Arctic Circle is not new, the Ardalin project is the first grassroots development of a major new oil field by a Russian joint venture.

The project posed unique challenges related to an aggressive schedule and budget and to constraints imposed by limited local infrastructure, unfamiliar cultures, unfamiliar regulatory requirements, and significant political uncertainty.

REMOTE AND MARSHY

The Ardalin field (Fig. 1) (52156 bytes) is approximately 1,000 miles northeast of Moscow, 90 miles north of the Arctic Circle, and 70 miles south of the Pechora Sea.

The terrain is marshy tundra covering discontinuous permafrost. Access by land is possible for only 5 winter months on trails provided for truck transportation through the region. The closest railroad is at Usinsk, 120 miles south.

A two-lane blacktop road runs from Usinsk to just north of Kharyaga, 30 miles southwest of the field.

Before the joint venture, Arkhangelskgeologia had drilled seven wells to delineate Ardalin. Three of these were completed by the joint venture in developmental drilling. No other assets were in place before field development work began in December 1992.

Ardalin holds a 37 API, high pour point (45 F.) crude oil which must be produced where temperatures of 50 F. are common.

Because initially the wells were anticipated to flow under their own pressures for only a short time, the design basis incorporates electric submersible pumps for each producing well. Preliminary reservoir studies called for development of three multiwell drill sites.

Despite the Russian practice of transporting produced fluids (both oil and water) long distances before separation, Polar Lights decided to de-water Ardalin production in the field because of capacity limits in the existing Kharyaga to Usinsk, two-phase pipeline.

Treated oil moves from Ardalin 42 miles in the aboveground arctic-quality pipeline to a purpose-built terminal at Kharyaga. Custody transfer to the existing Russian pipeline system occurs at the Kharyaga pipeline terminal.

Paragon Engineering Services, Houston, was engaged in late 1991 to perform the preliminary engineering for the Ardalin field complex and Kharyaga pipeline terminal. Early in 1992, Michael Baker Jr. Inc., Houma, La., was engaged as the engineering contractor for the Ardalin pipeline.

Both companies then joined forces with PechorNIPIneft, the technical design institute in Uktha, Komi Republic, to review Western designs for compliance with Russian codes and standards, to aid with permit requirements, and to complete pipeline routing.

Road and pad construction began at Ardalin in winter 1992-93 with work on the Ardalin pipeline beginning about the same time as well. Both activities continued through the spring thaw in April 1993.

Pile installation and civil work continued on the roads and pads at Ardalin during spring and summer 1993. During this period, upgraded Russian drilling rigs were moved onto the well pads and erected. The first wells were spudded in September-October.

During 1993, 13 shiploads (approximately equivalent to 1,000 shipping containers) of equipment, materials, and prefabricated modules were transported from the U. S. to Arkhangelsk and moved via rail and truck to a marshaling area some 30 miles southwest of Ardalin.

When an Alaskan-style snow and ice road was completed in December 1993, all equipment, modules, and containers were trucked to site. Hook-up and commissioning of the utilities, separation modules, and flow lines began in early 1994.

The pipeline was mechanically complete in March and hydrotested in June while the field facilities were mechanically complete in July 1994.

About 30 months after start of engineering, the field began to produce on Aug. 22. Costs for the facilities and pipeline were within 5% of the original estimate.

THE FIELD

Fig. 2 (68478 bytes) shows a plan view of the Ardalin field complex, and Fig. 3 (78728 bytes) presents a simplified process flow. Table 1 (30498 bytes) shows nominal capacities of the installed facilities.

ROADS AND QUARRIES

The in-field roads, well pads, and pad beneath the central production facilities are of gravel from two quarries created for this development.

The roads and pads are elevated 2-5 m above normal grade. Culverts allow surface water to pass freely beneath the roads in low areas, and one permanent steel bridge spans a seasonal river.

The roads provide year-round access to the well pads. During winter, the roads and pads freeze solidly, making travel easier. In summer, when the top 12-18 in. of the roads and pads turn to mud, wood mats are used to facilitate travel.

With oil field operations in Russia, the civil component of the job is much larger than for most onshore developments and it cannot be taken for granted. For Ardalin, two quarries were identified before the start of detail design.

There was, however, insufficient local earth-moving machinery and time in the schedule to allow a proper weathering and compacting cycle between initial pad and road construction and when the first heavy equipment had to begin work.

Consequently, the normal sequential activities of quarry development planning, permitting, excavating, stockpiling, thawing and draining, and construction all took place simultaneously and the desired summer weathering and compacting cycle was for the most part omitted.

Constructing roads with frozen material was difficult, but the gravel also consisted mostly of sand and silt. Furthermore, the lack of detailed topographical data, geotechnical surveys, and soil-strength data delayed quarry development and complicated civil design.

Changing regulations which increased the size of drill sites and the allowable distance between various operations also increased the civil work scope three-fold during the project. This had a significant impact on heavy equipment and personnel requirements given the remote work site.

Use of geotextile material to retain the sand and silt mitigated to some extent the effects of the poor material, but the roads and pads still required considerable maintenance during construction of the facilities.

Selective quarrying, sorting and stockpiling, and placement of gravel also helped solve some of the related problems. The only alternative to a summer weathering and compacting cycle was to build more than 5,000 wooden mats that were leap-frogged around as needed during the summer when the top 18 in. of the roads and pads thaw and turn to a thixotropic mud.

Besides being costly, the use of wooden mats is labor intensive because they must be removed, cleaned, and stored before onset of winter.

DRILL SITES

Each multiwell drill site, of which Drill Site C (Fig. 4) (84313 bytes) is typical, is designed to handle up to 10 wells. Additional wells could be added but the pads and well facilities modules would have to be extended. Directional wells are drilled in a line on 60 ft (18.3 m) centers and are tied back via insulated and heat-traced flow lines to enclosed elevated well modules.

The elevated well module houses the transformers, motor control centers, and variable-speed drives for electric submersible pumps, manifolds (production, test, water supply, and injection), pig launchers and receivers, and facilities for storage and injection of scale and corrosion inhibitors, emulsion breakers, and other production chemicals.

Each well is protected by a purpose-built insulated and heated well enclosure. The enclosures make data collection and well maintenance during the frigid winter months easier. Wireline operations can be performed through the roof, and the enclosure can be removed for rig access.

Each drill site has its own dedicated diesel-fuel storage tanks, solids-handling system, temporary living quarters for the drilling crew, and drilling office. The 3D-86 Uralmash Russian rigs have been upgraded with western pipe handling, solids control, and other safety equipment, and the mud tanks, chemical storage, and solids-handling equipment are enclosed.

The single well sites for the three existing appraisal wells are scaled-down versions of the multiwell drill site with the major exception being that they have no drilling rig.

FLOW LINES

All flow lines are elevated on vertical support members, which for the most part consist of 8-in. piles and I-beam cross supports. The members also support the 6-kv power cable that runs from the utility modules at the central production facility to each of the drill sites. Separate bulk production and test lines flow from each well pad to the production facility.

All flow lines are insulated with polyurethane foam. The water supply and injection lines are also protected by a combination of conventional resistance and heat tracing.

Production and test lines from the multiwell pads are not heat-traced their full lengths because warm fluids can readily be circulated through these lines if production is temporarily interrupted.

CENTRAL FACILITIES

The central production facilities consist of living quarters, utility modules, process modules, tank battery, and waterflood plant. Fig. 5 (83988 bytes) shows the pad. To protect the permafrost, all modules and tanks rest at least 2 m above the gravel pad.

LIVING QUARTERS; UTILITY MODULES

The permanent living quarters consist of roughly 40, 100-person prefabricated modules that were transported by helicopter to site in October 1993. This was done to accelerate the construction effort and increase the total number of beds available for construction personnel.

A long insulated and enclosed utilidor connects the living quarters with the maintenance shop and helps reduce workers exposure to winter elements.

The utility complex consists of 32 modules that provide primary and emergency power generation, potable water and firewater systems, sewage treatment, space and process heating, N2 generation, solid-waste incineration, and instrument air.

Primary power generation consists of three identical 3.8 mw dual-fuel, turbine-generator sets and backup power of two 1,000-kw diesel engine-driven generator sets.

Two, duel-fuel, direct-fired heaters, each rated at 28 MMBTU/hr, provide space and process heat.

Potable water comes from Jurassic source water via two reverse-osmosis units each capable of processing 6,000 gpd.

Firewater is supplied by two 40-hp diesel engine-driven pumps.

Sewage and similar wastes are processed in two 5,000 gpd sewage units. The process is carefully controlled to produce a solid sludge which is mixed with diesel and burned in two solid-waste incinerators.

A selective membrane generates nitrogen from air. The unit is driven by a 220 hp screw-type compressor. Nitrogen is used as purge gas within the modules and flare and to blanket the crude oil and diesel tanks.

Instrument and utility air are generated by two, 100%, instrument-air compressors, each sized to supply 130 cfm at 150 psig. Air is dried to 2100 F. dew point.

PROCESS MODULES

Twenty-nine process modules provide oil, gas, and water separation. Fluids from the various well pads enter a three-phase, high-pressure separator which operates at roughly 240 psig. Gas is used for turbine fuel. Oil is heated to 180 F. and flows on to the three-phase, low-pressure (15 psig) separator, and water flows to the hydrocyclone units for de-oiling.

Well tests are performed via a test separator that can also operate in parallel to the high-pressure separator. Excess fuel gas goes to a smokeless flare designed to burn all the hydrocarbons vented from the process facilities in an emergency or process upset at low enough radiation levels so there is no effect on the permafrost.

From the produced-water hydrocyclone, the oil phase is directed to the low-pressure separator and the water stream to a horizontal flash vessel which operates at 3 psig.

Produced water from the flash vessel is filtered via two, 100% cartridge filters which remove solids greater than 25 . The water then can either be reinjected directly or sent to the waterflood plant for further filtration.

The Ardalin process safety systems are based on the requirements of API RP 14C, except where inappropriate for a shore facility. Fire and gas detectors are provided in the process area and the water flood area.

The process area is isolated from the utility area by an open walkway to provide a noncommunicating air break. A similar air break is provided between the utility area and the living quarters and between the production area and the water flood area.

Upon detection of gas or fire, all incoming hydrocarbon sources are shut in, and the separators are depressured. Fire suppression is provided in the living quarters and generator set enclosures.

For safety and control, all chemical storage and injection are performed centrally in three purpose-built modules located side by side.

The tank battery consists of four crude tanks and one diesel tank. Combined volume of the crude-oil storage tanks is purposely designed to be 1.3 times that of the Ardalin pipeline so that warm crude can be shuttled back and forth between Ardalin and Kharyaga if the Russian pipeline system is shut-in south of Kharyaga during the winter months.

The waterflood plant consists of 12 dedicated modules located at the south end of the central production pad. The plant contains equipment to strain and filter low-salinity source water produced from the Jurassic water-supply wells; filter, de-oil, and polish produced water; add chemicals as required; and raise the pressure of the injected water to approximately 2,700 psig.

MODULE DESIGN, FABRICATION

Procurement and construction for the facilities were set by the weather window for ice-road transportation to site. Furthermore, since road transportation was impossible until early winter, site construction was forced into the worst weather period.

Design was therefore affected by the need for minimum transportation risk, coupled with minimum site erection work. To satisfy these two conditions, three alternative construction and installation strategies were considered:

  • Fabrication of a minimum number of large modules (as common on the North Slope)
  • Site-erected buildings with skids erected and hooked-up inside
  • Prefabricated minimodules hooked-up to form large, single-story buildings

Transportation and constructability studies showed the third alternative offered the least risk and maximum flexibility of transportation modes, and the minimum site hook-up work.

Efforts were made to utilize Russian materials such as concrete slabs, structural steel, wood, diesel fuel, and various vehicles. These efforts were for the most part successful.

Major equipment, however, was largely Western due to schedule constraints which did not allow time to search and assess the Russian market. Title/ownership, payment, warranty, lack of design/performance data, delivery guarantees were all obstacles to incorporating more Russian equipment into the design.

Even construction equipment was difficult to come by for similar reasons.

Over the past 2 years, more Russian suppliers have become aware of Western quality-control requirements and methods of doing business. In addition, there are now more joint-venture agreements between Western suppliers and fabrication companies and their Russian counterparts which might allow greater Russian supply.

A transportation study was performed to establish the largest module size which could be shipped by any available method. The possible methods identified were road, rail, river barge, freight aircraft, and helicopter.

The maximum dimensions selected were 39 x 11 x 12 ft high, set by the size of routinely available rail cars and clearances along the possible routes. The shipping weight was set at 30 tons by the capacity of locally available trucks and the weight limits of some roads and bridges.

Of approximately 100 facility modules, only 15 weighed more than 30 tons. The heaviest was 52 tons. It was impractical to reduce the shipping weight of these modules, and special precautions had to be taken during their transportation.

To facilitate assembly-line fabrication, the basic structural design of each module was kept the same. All modules were provided with top-mounted lifting eyes for single point lifts during shipment at harbors and Russian rail sidings. As much of the outfitting work as possible was performed before the deadline for trans-Atlantic shipment to Russia.

ARDALIN PIPELINE

The Ardalin pipeline is 42 miles of 12 in. x 0.375-in. W.T. arctic grade X-65 seamless pipe. It is coated with 15 mils of fusion-bonded epoxy (FBE), 3 in. of dense (112 kg/sq m) durable polyurethane foam insulation, and a 30-gauge (1-mm) galvanized metal jacket.

The result is a low overall heat-transfer coefficient of 0.05 BTU/hr-sq ft-F. The pipeline is rated for a maximum allowable working pressure (MAOP) of 1,995 psig at 250 F.

Although design throughput at MAOP is 80,000 bo/d, current throughput is limited to a nominal 25,000 bo/d by the size of the export pump at Ardalin. At this rate, the normal discharge pressure at Ardalin is about 200 psig.

The pipeline runs from Ardalin to Kharyaga along high ground. Along its length, the pipeline negotiates 4 purpose-built animal crossings, 9 stream crossings, 12 road crossings (11 buried and 1 overhead), and a major river crossing.

The animal crossings are sections roughly 100 m long where the pipeline has been run through a 30-in. casing.

At the Kolva River, the pipeline is attached to specially designed supports which are fastened to the steel I beam which runs along the underside of the Kolva River bridge so that it is completely protected from vehicles.

The pipeline is equipped with four fullbore block valves; one at each end and two at the Kolva River to minimize spill potential should a problem arise. The two valves at the Kolva River are designed to shut automatically on low pressure.

Thermal expansion in the pipeline is dealt with via 151 rectangular expansion loops that measure roughly 39 x 90 ft. The expansion loops are spaced 1,500 ft apart, and the pipeline is rigidly anchored midway between expansion joints to ensure that linear changes are uniformly distributed.

The pipeline is supported aboveground by 4,820 vertical support members which are spaced roughly 55 ft apart.

The T cross-beams are designed so that a second pipeline can be run in parallel if needed.

In general, the pipeline elevation runs 1-3 ft above the ground and only occasionally reaches a maximum elevation of 10 ft when necessary to adjust to rapid fluctuations in ground elevation.

KHARYAGA TERMINAL

The main functions performed by the Kharyaga pipeline terminal include crude-oil storage (4 x 10,000 bbl), fiscal metering and product export (25,000 b/d), heat addition (2 x 15 MMBTU/hr), crude shuttling operations between Ardalin and the terminal, chemical injection (drag reducing agent), and pipeline maintenance (pig launching and receiving).

Fig. 6 (78860 bytes) shows the arrangement of the 328 x 500 ft terminal pad. The tank battery consists of five tanks: four 10,000 bbl tanks for oil storage and one 1,200 bbl tank for arctic diesel storage.

The construction of the crude-oil storage tanks is identical to those at Ardalin. Normally, three of the crude-oil storage tanks are kept full should the need arise to shuttle crude back and forth between Ardalin and the terminal to keep the pipeline warm.

Crude is pumped from the tanks through a shell-and-tube heat exchanger which heats the oil to roughly 180 F. Heat is supplied by two dual-fueled, 15 MMBTU/hr heaters and glycol circulation.

During export, the oil first flows through a fully automated lease automatic custody transfer (LACT) and prover unit after which a single 550-hp sales pump raises the pressure to 900 psig.

The oil leaves the terminal and travels 0.5 mile before it enters the Komineft pipeline network which originates in Kharyaga and transports oil 88 miles south to Usinsk.

The terminal is hooked to local electric-power distribution at two points, and gas is purchased from Arkhangelskneftigas for both heating and tank blanketing. Three 400-kw, diesel engine-driven generators provide electrical back-up at 380 v.

DESIGN PHILOSOPHY

The emphasis during design was to achieve the earliest possible production start-up, keep operations simple, minimize capital costs, and maximize safety for operating personnel and protection of the environment.

Another goal was to maximize local content of materials and construction labor. But it was recognized that the fast-track nature of the project and lack of knowledge of the availability of goods and services in Russia would make this goal difficult.

To hold down capital costs, it was decided to phase-in production capacity pending a better understanding of the reservoir, of other potential reservoirs nearby, and of the economics of doing business in this frontier.

The facilities were designed to be expandable to 50,000 bo/d, but only those necessary for 25,000 bo/d were installed initially. Additional throughput can be achieved by adding pipeline pumps and parallel process modules, with minor additions to utility and life-support modules.

This approach has proven wise because the reservoir characterization changed several times during the course of the project thanks to new seismic data and interpretations.

WORKING IN RUSSIA

Using Russian workers and negotiating the Russian permitting process taught some valuable lessons for future projects.

RUSSIAN LABOR

Mostly Russian workers were used for site preparation, in-land transportation, module installation, hook-up, and commissioning. During the winters, more than 1,000 people worked on the project each day at several sites from Usinsk to Ardalin, with 90% being Russian.

For the pipeline, a highly competent Russian contractor provided most of the pipeline construction personnel. He was not local to the region and lacked sufficient equipment to do the job to Western standards.

But he had the required expertise and agreed to receive Western pile driving, welding, and safety equipment as partial compensation. A small team of Conoco pipeline experts provided direction and quality assurance and control.

Although our experience with Russian labor has been very favorable, local supervisors were unaccustomed to monitoring work routinely for cost and productivity and to making adjustments when necessary.

This had to be done by Western site superintendents and construction managers. In time, some Russian craftsmen were promoted to foremen and replaced Westerners.

The need for permanent full-time translators diminished as Western foremen and Russian craftsmen learned to communicate.

PERMITTING

The feasibility study which formed the basis of the AFE was utilized for the first round of approvals in Moscow, but the level of detail proved to be more than the Russians required at that stage.

This caused confusion, especially when subsequent documents conflicted with the original submittals.

Westerners proceed with commitments to projects without detailed definition, modify original concepts to get on stream as quickly as possible, and feel comfortable with mid-project design changes if they enhance the value of the project.

The practice in Russia, however, is to proceed in a series of steps, completing each one before the start of the next. As the design evolves, Russians tend to be uncomfortable changing previous decisions in light of new technical knowledge or to maintain the project schedule.

The decision to use PechnorNIPIneft, the technical design institute for the Komi Republic in Ukhta, to review the design and aid in the permit process proved wise. Both Conoco and Paragon personnel worked in Ukhta on a 28-day on 28-day off rotation.

The steps required to obtain local permits for the design, construction, and operation of an oil and gas production facility were explained by the institute. But it remained unclear what permit information was to be submitted, what the preferred format was, and at what time in the project schedule the permit documentation was to be submitted.

Kulish has offered additional comments on working with design institutes.1

ACKNOWLEDGEMENT

The authors wish to thank Polar Lights Joint Venture for approving release of this article.

REFERENCE

  1. Kulish, Kevin, Designing Oil and Gas Facilities for Russia, 1994 SPE Annual Technical Conference and Exhibition.

THE AUTHORS

Michael W. Britton was overall project manager (pipeline and facilities) for the Ardalin project and is currently assigned to Conoco Inc.s project with Maraven in Venezuela. He holds BS and MS degrees in chemical engineering from the University of Michigan and is a member of SPE.
Robert Speirs was facilities project manager for Ardalin and is currently leader of the project development group in exploration production for Conoco Inc., Houston. He holds a BS in engineering science from the University of Edinburgh. Speirs is a chartered engineer and a member of the Institute for Electrical Engineers.
Gordon Pace is a project manager for Paragon Engineering Services, Houston, a firm he joined in 1988. He holds a BS in fuel science from the University of Leeds, England.
Carlton T. Sikes is engineering manager for Paragon Engineering Services where he has held various positions since joining the firm in 1984. He holds a BS in chemical engineering from Texas A&M University.

Copyright 1995 Oil & Gas Journal. All Rights Reserved.