TECHNOLOGY Cooperation, logistics critical to well control operation in Irian Jaya jungle

Freddy Gebhardt
Wild Well Control Inc.
Spring, Tex.

Richard Leturno
Atlantic Richfield Indonesia Inc.
Jakarta

Solving a well control problem in remote Irian Jaya, Indonesia, required fast regional and international transportation of both people and equipment.

Methods of mobilization included commercial air carrier, cargo charter, helicopter charter, barge, landing craft, and small boat. The sourcing and mobilization of suitable equipment from within the region proved to be a major facet of the operation, as well as managing the human resources of the operator. Concerns of well stability and crew safety also affected logistics.

The well is approximately 3 km from the coast and 120 km from the nearest large airstrip in Irian Jaya, formerly New Guinea. The well is in a remote jungle location that is accessible only by helicopter.

The staging area normally used to support drilling operations was 5 min away via helicopter. All equipment and material were transported to the staging area via ocean-going barges then airlifted (short-lined) to the well site.

Initial information indicated that the well was experiencing an underground flow with a constant surface pressure because of a shallow hole in the 95/8-in. casing. The surface pressure made pipe movement inadvisable until proper pressure control equipment was in place.

The bottom hole assembly configuration would not allow the drillstring to be stripped to the bottom of the well. An off-bottom kill was not possible at the current depth. Partial circulation was maintained, preventing gas migration to the surface and lowering the wellhead pressure considerably. Numerous cement squeezes were attempted without positive results. Gas analysis and a review of the drilling reports identified the likely source of the flow.

Initial actions

Once the initial well information had been gathered and analyzed, Atlantic Richfield Indonesia Inc. (ARII), the well operator, activated its well control task group. ARII had previously identified various team members from all sectors of its organization who would be called upon to undertake specific duties depending on the nature of the event.

The ARII well control task group compiled all available well data and contacted ARCO International Oil & Gas Co. (Aiogc) headquarters in Plano, Tex. Aiogc implemented the technical support group. After discussing the well condition, Aiogc contacted Wild Well Control Inc. (WWCI).

Well control specialists from WWCI's offices in Spring, Tex., went to Plano to confer with Aiogc's technical support team. Following an initial review of the situation, a decision was made to send two well control specialists to the well site, while an engineer from WWCI's engineering division would remain in Plano and join Aiogc's technical support team.

The well control team was mobilized to Indonesia in approximately 36 hr. While the well control team was in route, the well control task group and technical support group further analyzed the well data. From this work, several possible intervention scenarios were developed prior to the well control team's arrival in Indonesia.

The well control team went to ARII's office where a meeting was held with the ARII well control task group. The previously developed intervention scenarios were discussed along with all other pertinent well data. The meeting was adjourned and the well control team departed Jakarta for Sorong, Irian Jaya, the next morning.

Once on location, the well control team was briefed by the ARII company representative. All safety plans were discussed, and a safety orientation of the rig site was completed.

The well site was a remote jungle location situated near a large river in a swamp-like environment. Well site equipment, such as the drilling rig, cementing unit, living quarters, and all other facilities were elevated approximately 1 m above the surrounding terrain. The well site pad was fabricated of lumber (board-road type) with all load-bearing areas (rig support base and two helipads) supported by structural steel welded onto casing pylons (Fig. 1 [48056 bytes]).

Following the well control team's initial consultation with ARII on site personnel, the following activities were initiated:

• Additional data were obtained by observing the reaction to various pumping activities.

• An additional choke line was installed to be used in case wellhead pressures increased dramatically.

• Two additional helipads were constructed farther away from the well site as a contingency in case the situation deteriorated.

• Additional living quarters and support facilities were added to accommodate the increased activity at the well site.

• Additional communications equipment was in stalled to support planning and intervention activities.

The staging facilities normally used to support drilling operations were evaluated and found to be adequate for the intervention. The staging area was located approximately 5 miles from the well site and was constructed in a manner similar to the load-bearing sites on the location. The staging area could receive all supplies via boat or barge and allow subsequent transportation to the well site by helicopter. Two helicopters were assigned to the support base along with flight and ground crews.

All equipment was stored aboard barges on the river. The barges required a mooring and bulkhead system designed to handle the strong outward current on the river.

Equipment selection

A complete evaluation of the situation confirmed that snubbing intervention would be the most expedient means to resolve the well control problem. A decision was made to use regionally available service companies to the extent possible. This decision was based on logistics, cost, and importation considerations.

The first step involved deciding which type of snubbing equipment (conventional or hydraulic) to use. This decision consisted of the following factors:

• Safety and reliability

• Availability of each type of snubbing equipment in the region

• Component weight and transportability (6,000-lb maximum lift)

• Space restrictions (small derrick)

• Day rates and operational time associated with each type.

Hydraulic snubbing equipment was available in the region; however, mobilization of conventional snubbing equipment could be justified based on cost alone. The decision to use hydraulic snubbing equipment was made primarily because of the need to remove the 43/4-in. spiral drill collars. Although this procedure can be accomplished with either type of snubbing equipment, hydraulic snubbing units provide a greater degree of control and safety.

One well control specialist was sent to inspect and test the snubbing and blowout preventer (BOP) equipment available in the region. This inspection was necessary to evaluate the suitability and reliability of the equipment for use on a critical well situation. The second well control specialist remained at the well site and directed preparations for installation of the snubbing and BOP equipment.

A number of BOPs were inspected and evaluated for use on the snubbing operation. Many of these BOPs had not been used regularly, and their condition had deteriorated from a lack of maintenance. A program was developed to transport the BOP equipment to a nearby location for further inspection and testing.

ARII requested and received permission to use Sante Fe Energy Resources' Kasim marine terminal (KMT) for equipment staging and testing. KMT, located 42 miles South of Jefman Airport (near Sorong), had living quarters and testing/repair facilities which proved crucial to the operation. New sealing elements and rebuild kits were ordered from the U.S., as none were locally available. A WWCI BOP technician was sent to KMT to direct the BOP testing and reconditioning.

A Hydra-Rig model 225K hydraulic snubbing unit was available in the region. The snubbing jack and associated equipment were in good working condition and suitable for critical well operations.

The snubbing equipment was flown directly to Jefman Airport for subsequent transport and staging at KMT. Upon arrival at Jefman Airport via C-130 cargo aircraft, all equipment was transported to KMT via an LCT (self-powered barge used for transporting equipment in protected waterways). Four C-130 air-charter equipment loads were required from various points within the region, and one small load was transported via scheduled air freight from the U.S.

A special ramp was constructed at Jefman Airport to facilitate equipment loading onto the LCT. Mobilization from KMT to the well site staging area was done with an ocean-going barge (Fig. 2 [73540 bytes]).

The WWCI BOP technician, one crew member from the snubbing company, and the KMT BOP repair facility crew performed the following tasks:

• Checked and assembled equipment as it arrived

• Prioritized equipment for the ocean-going barge

• Initiated repairs on all BOPs, valves, HCRs, manifolds, and other pressure control equipment

• Pressure/function tested all BOPs to American Petroleum Institute standards

• Disassembled and prioritized the equipment into 6,000-lb loads for the helicopter lift to the well site

• Determined the lift sequence for all equipment, and loaded the barge accordingly.

Staging area

It was critical to remove all nonessential equipment from the rig site and either move it to the staging area or set the pieces to the side of the elevated rig base. There were three areas suitable for equipment placement (Fig. 1 [48056 bytes]):

• Between the pipe rack and the catwalk

• On the small helipad on the pump side of the rig (flare area)

• On top of the pipe rack.

Equipment offloading at the well site staging area had to be done in a specified sequence for operational purposes. This offloading required constant communication and coordination between the well site and KMT where the equipment was loaded onto the ocean-going barge.

Prior to the equipment's arrival at the well site staging area, every lift basket, BOP, and component of the snubbing unit was numbered in sequential order. There were four distinct phases to the airlift operation:

1. Move in initial BOP equipment; reassemble, test, and install the equipment on the well.

2. Move in remaining BOP equipment; reassemble, test, and install the remaining equipment on the well.

3. Move in the snubbing unit jack, power pack, and related equipment; reassemble the snubbing jack, and rig up.

4. Move in miscellaneous support equipment (tongs, valve assemblies, etc.).

The space restrictions imposed by the small well site prevented placing all the equipment on location at once.

Two helicopters supported the project: a Super Puma with a maximum lift of 6,000 lb (2,722 kg) and a Sikorsky with a maximum lift of 2,800 lb (1,270 kg). To use the lifting capacity of the helicopters efficiently, the equipment was broken down into small loads (Table 1 [24236 bytes]).

While assembly and testing were under way at the KMT facility, the well site personnel prepared to handle the snubbing equipment. A sufficient crane was not available to set components onto the rig floor, and it was impractical to have one mobilized to the site.

A snub/lift system was devised to use the rig blocks to lift and install all BOP and snubbing components safely. A 10,000-lb capacity hy draulic winch was ordered for use with this system. This system permitted the snubbing equipment to be raised and lowered without pulling the rig blocks off center. The hydraulic winch snubbed each component while it was moving up or down the V-door.

The following activities prepared the rig for installation of the snubbing equipment:

• Installation of the hydraulic winch at the end of the catwalk

• Removal of the bell nipple from rig annular preventer

• Installation of a 3/4-in. static line from the crown to rig floor

• Installation of sling/sheave system on the rig blocks to ride on static line.

Snubbing well control

Snubbing operations began once all equipment was installed and properly tested. Freshwater was injected down the annulus during snubbing operations to minimize wellhead pressure and prevent gas migration to the surface.

The following is a brief synopsis of the snubbing operations:

• The drillstring, consisting of 31/2-in. drill pipe and 43/4-in. spiral drill collars, was removed under pressure. The spiral drill collars were successfully stripped out using a tandem annular configuration.

• A 7-in. cement retainer was run and set in the bottom section of the 7-in. liner. This retainer isolated the flow source from the hole in the 95/8-in. casing.

• A 95/8-in. retrievable test packer was set above the hole in the 95/8-in. casing. A successful test of the 95/8-in. casing above the packer was conducted. This procedure confirmed the pressure integrity of the 95/8-in. casing above the hole.

• A 95/8-in. squeeze packer was run, and a cement squeeze job was performed. The 95/8-in. casing was successfully pressure tested following the cement squeeze.

• A bit and scraper run was completed, and again the casing was successfully tested.

• The well was monitored at zero pressure, and the snubbing equipment was rigged down.

• A 7-in. liner was run with a 95/8-in. external casing packer to isolate the 95/8-in. casing section. The cement job and setting of the external casing packer were completed. The cement was allowed to set up for 24 hr and was then tested successfully.

• The snubbing unit and related equipment were demobilized.

Results

Several factors contributed to the overall success of this well control project.

ARII's commitment to blowout contingency planning and well control team made it possible to institute a predetermined organizational structure. This organizational structure provided a means to gather and evaluate data quickly. Thus, crucial decisions could be made without delay, and proper personnel and equipment were mobilized.

The seamless cooperation between ARII and Aiogc allowed crucial technical support to be provided in the most useful fashion.

A strong working relationship had been previously developed between ARCO and WWCI, primarily through contingency exercises and pre-event planning. These exercises established a relationship which allowed a smooth interface between the operator and the well control company.

The cooperation of other operators within the region was crucial to the timely success of the project. In particular, Santa Fe Resources provided access and use of the KMT facility, which proved to be instrumental in the success of the operation. In addition, Unocal-Thailand released the snubbing unit from a scheduled multiwell workover program. This cooperation minimized mobilization times and costs tremendously.

The commendable efforts of several local service companies were key aspects in the massive mobilization project.

Acknowledgment

The authors wish to thank ARCO International Oil & Gas Co. and Atlantic Richfield Indonesia Inc. for permission to publish this article. The authors also thank Atlantic Richfield Wiriager, KG Wiriager Petroleum Ltd., Pertamina, and David Barnett with Wild Well Control Inc.'s engineering division.

Based on a presentation at the International Association of Drilling Contractors Well Control Conference for the Asia/Pacific Region, Nov. 29-Dec. 1, 1995.

The Authors