Production platform in giant Bongkot gas field in the southern Gulf of Thailand is operated by a group led by Total. E&D activity is accelerating in the region, notably in a hot new area jointly administered by Malaysia and Thailand. Photo courtesy Total.
The southern Gulf of Thailand is shaping up as a hot exploration and development play.
Carigali-Triton Operating Co. (CTOC) is moving ahead with plans to begin developing gas discoveries in the Malaysia-Thailand Joint Development Area (JDA) in the southern Gulf of Thailand.
CTOC has deferred further appraisal of Block A-18's Cakerawala field in favor of finishing design by yearend 1996 of the field's development program. Also by yearend, CTOC officials expect to conclude a sales contract for Cakerawala gas output.
In addition, delineating drilling is to proceed at Suriya field, also discovered on the 726,474 acre Block A-18 tract.
CTOC also plans to spud 1 Buma wildcat at a site about 9 miles east of Cakerawala field and adjacent to Suriya (see map, OGJ, Mar. 25, p. 28).
Elsewhere in the southern Gulf of Thailand, the upstream arm of state owned Petroleum Authority of Thailand (PTT), PTT Exploration & Production plc (Pttep), is seeking co-venturers for its recently acquired gas-prospective concession block near Bongkot, one of the largest gas fields in the gulf.
A group led by Total recently hammered out an agreement to boost gas deliveries from Bongkot field, enhancing the attractiveness of the Pttep block.
JDA action
News of CTOC's new plans came in mid-July with release of the company's most recent drilling results on Block A-18, in northern Malay basin about 280 miles from Kuala Lumpur and 465 miles from Bangkok (OGJ, July 22, p. 30).
CTOC said 3 Cakerawala appraisal well confirmed the presence of gas in the southwest part of the field and penetrated a previously unknown oil accumulation. CTOC's 1 Bulan wildcat discovered Block A-18's third gas accumulation, while 3 Cakerawala marked the company's sixth successful gas well on Block A-18.
CTOC plans to use the same semisubmersible drilling rig that drilled 3 Cakerawala to drill 1 Bumi. The company is to drill the Suriya appraisal well with the rig that drilled 1 Bulan.
Early completion in late 1995 of a 237 sq mile 3D seismic survey over the central part of Block A-18 is speeding Cakerawala field's appraisal program and development planning, as well as the drilling of 1 Bulan.
Cakerawala activity update
CTOC's 3 Cakerawala was the second well in a drilling program to define the areal extent of Cakerawala field and evaluate primarily shallow and intermediate zones on the structure.
The well's chief objectives were to evaluate the discovery, including CTOC's ability to produce gas and oil from the southwestern portion of the field.
Officials said 3 Cakerawala in tests of five intervals at 3,960-6,870 ft flowed at a combined rate of 47 MMcfd of gas and 225 b/d of 41-52° gravity condensate through various chokes. CTOC drilled 3 Cakerawala in about 180 ft of water at a site about 2 miles west-northwest of field discovery well 1A Cakerawala.
CTOC must conduct more tests to determine the size of the oil reservoir discovered by 3 Cakerawala. The oil interval in tests flowed 3,002 b/d of 37° gravity oil through a 2 in. choke.
Al Turner, senior vice-president of operations at Triton Energy Ltd., Dallas, said discovering the oil reservoir was a positive surprise.
"We are pleased with the high flow rate and the quality of the oil, which will be a consideration in the field's development program as we move forward," Turner said.
CTOC is owned 50-50 by Triton Oil Co. of Thailand (JDA) Ltd. unit of Triton Energy Ltd., Dallas, and Petronas Carigali (JDA) Sdn. Bhd. unit of Malaysia's state owned Petroliam Nasional Bhd.
Bulan wildcat details
CTOC drilled 1 Bulan to 7,140 ft TD on a previously untested structure to explore normally pressured, shallow zones at about 4,000-6,400 ft and intermediate zones exhibiting increasing pressure and temperature from 6,400 ft to TD.
The 1 Bulan well is in 180 ft of water about 4.5 miles west-northwest of 1A Cakerawala wildcat.
The company gauged a combined flow on 1 Bulan wildcat of 36 MMcfd of gas and 123 b/d of 39-53° gravity condensate through chokes of 56/64-96/64 in. with drill stem tests of three intervals at 4,044-6,842 ft.
"It is gratifying to discover a third gas field on Block A-18," said Nick De'Ath, Triton senior vice-president of exploration. "This hydrocarbon-rich area of the Gulf of Thailand has great potential, and we look forward to working with our partner, Petronas Carigali, and the Malaysia-Thailand Joint Authority (MTJA) on a fast-paced development program."
CTOC earlier this year drilled 1 Cakerawala East wildcat on a separate fault block at a site about 2.5 miles southeast of 1A Cakerawala. The company drilled the well to test deep, high temperature, high pressure sands, but results were inconclusive (OGJ, Mar. 25, p. 27).
JDA gas accord
MTJA and its two production-sharing contractors recently signed a memorandum of understanding to sell natural gas discovered on JDA acreage to the Thai and Malaysian state oil concerns.
The memorandum of understanding lays the guidelines and groundwork for MTJA and its contractors Pttep and Petronas Carigali to negotiate for the sale of natural gas from Blocks B-17 and C-19 to PTT and Petronas.
That followed a letter of intent signed in March that called for PTT and Petronas to purchase gas from several JDA gas-related joint ventures.
But the latter memorandum deals specifically with gas from B-17 and C-19, two of three blocks lying in the JDA. The other is Block A-18.
According to Pttep, the memorandum sets forth 2000 as the target date for bringing natural gas from Blocks B-17 and C-19 into production. The gas delivery rate has not been specified and depends on further confirmation of gas reserves on the blocks.
So far, Pttep-Petronas Carigali joint venture has discovered two gas fields on Block B17, Muda and Tapi. The 1 Muda wildcat, about 290 km east of Thailand's Songkhla coast, is the most productive exploratory well drilled to date in the JDA. It flowed on test natural gas from a number of zones at a combined rate of about 70 MMcfd and 726 b/d of condensate.
Early this year, Pttep-Petronas Carigali completed an additional 3D seismic campaign of 1,100 sq km. As part of its continuing exploration program, the venture also plans to drill one wildcat and two appraisal wells on its tracts this year.
Although PTT and Petronas were described as "potential buyers" of the B-17 and C-19 gas in the memorandum, PTT appears keener to purchase the gas and transport it via pipeline to Thailand to meet soaring domestic gas demand, especially for power generation.
Gas supply hunt
PTT has been looking for additional natural gas supplies from neighboring countries including Myanmar, Malay- sia, Cambodia, and Viet Nam, as well as domestic fields to meet Thailand's burgeoning gas demand.
Gas discovered in the JDA is split equally between Thailand and Malaysia through MTJA. MTJA is vested with the exclusive rights of exploring and developing petroleum resources in the JDA under a memorandum of understanding the Thai and Malaysian governments signed in 1979. That agreement ended decades of disputes over which nation owned petroleum deposits underlying the territorial claims.
Malaysia and Thailand are becoming optimistic of a gas development boom in the JDA, following what appeared to be promising gas finds. Through the latest appraisal drilling, about 6-7 tcf of gas reserves are believed to be contained in the once-disputed waters.
That led the two to signed the letter of intent Mar. 5 to establish a gas supply deal and principles for other joint venture projects involving the utilization of JDA gas, such as power generation and petrochemicals, subject to approval from their respective governments.
These "strategic alliances" will not be restricted to Thailand but can expand to Malaysia and other countries in Southeast Asia.
While exploration is continuing in JDA, PTT and Petronas officials have estimated discoveries made to date could support gas production at the rate of 300-500 MMcfd.
Block partners sought
A company source said Pttep's current partners in the Bongkot development project-Total, British Gas plc, and Norway's state owned Den norske stats oljeselskap (Statoil)-are the most likely candidates for partnership in Block B-13/38, now wholly owned by Pttep.
Although other international candidates for partnership are not ruled out at this stage, Pttep is focusing on this trio because of their current working and equity relationships in Bongkot as well as their experience and knowledge of the geological condition in the general area of Bongkot, the source said.
For now, Pttep has not decided on the size of stake in the 655 sq km tract it wants to allocate to its potential partners, depending on negotiations still to come.
But one possibility is to follow the same arrangement as in the Bongkot scheme. That called for Pttep to reduce its stake in B-13/38 to 40% while allowing Total to retain a 30% share and assume the operatorship, with interests for British Gas of 20% and Statoil 10%.
The idea is to ensure that exploration and development of gas reserves on B-13/38, south of Bongkot, is carried out in concert with Bongkot development, whose facilities could accommodate the new production.
Based on previous geological studies and exploration work undertaken in Bongkot, now producing 350 MMcfd, Pttep believes there is good potential for hydrocarbon accumulation on Block B-13/38.
Under the terms Pttep entered into with Thailand's Industry Ministry June 27, the company is committed to a minimum outlay of $2.68 million in the first 3 year obligation period for exploration work on the block. Pttep is required to spend at least $2.4 million for further exploration in the subsequent 3 years, if it opts to extend.
Bongkot sales accord
The Total group recently reached an accord to boost natural gas delivery from Bongkot to PTT by 57% from the current contract level.
The agreement followed tough negotiations in which the concessionaire group has demanded a higher gas tariff to justify millions of dollars in additional investment required for increasing gas production under Phase III development. The agreed new wellhead price was not disclosed.
According to PTT, the group is due to increase Bongkot gas delivery from 350 MMcfd in the current contract year to 550 MMcfd in mid-1998.
Pttep, which has a 40% interest in Bongkot, said the increase in gas production results from another gas discovery on the block, south of Bongkot, and the Ion Suk structure east of Bongkot.
The agreement sets the stage for further development of Bongkot, by far the country's single largest gas field.
But Jean Paul Azalbert, general manager of Bongkot operator Total Exploration & Production Thailand, said it is too early to discuss details of the Phase III development, as the agreement with PTT has yet to be endorsed by the boards of the Bongkot partners and the project has not been given a formal go-ahead by the joint venture.
However, PTT and Pttep have already approved the new gas supply accord.
Azalbert noted Phase II development of Bongkot, officially inaugurated in April at a cost of $200 million, has boosted the field's production capacity to more than 400 MMcfd of gas and 7,000 b/d of condensate.
Phase II development included installation of three new wellhead platforms, a riser platform, and a remote flare near the existing production facilities as well as drilling of 23 new development wells.
Since the inception of Bongkot's production in July 1993, the field has produced 222 bcf of gas and 4 million bbl of condensate.
Copyright 1996 Oil & Gas Journal. All Rights Reserved.
