Located offshore approximately 150km from Kota Bharu and 260km from Songkhla in the Gulf of Thailand, the area is approximately 7,250 square kilometers in size. Geologically, this overlapping area, situated in the northern part of the prolific Malay Basin, is known for its hydrocarbon potential.

The MTJA, with its Head Office located in Kuala Lumpur, is governed by a Board with Members consisting of equal representatives of Malaysian and Thai nationals (7 from each side) as appointed by the respective Governments. Under the supervision of MTJA Board, the MTJA Management consists of staff covering technical, legal and financial aspects of the petroleum business.

The MTJA prides itself as being one of the world's first to implement this unique cooperation between two countries. This cooperation has mutually benefitted the people of Malaysia and the Kingdom of Thailand.

The MTJA Management supervises, facilitates, and monitors petroleum exploration, development and production activities of the Production Sharing Contractors (PSC) in Block A-18, Blocks-17 & C-19 and Block B-17-01 of the Joint Development Area.

Geologically, the JDA lies in the northern part of the prolific Malay Basin where thick sediments of Tertiary sandstones, siltstones and shales are abundant which provide source as well as reservoir for oil and gas.

Prior to the signing of the MOU in 1979, a Contractor from Malaysia had drilled one well, the Pilong-1, in 1971 and discovered gas. This area was then relinquished. In the neighbouring area, a concessionaire from Thailand had also drilled one well, the 17-B-1 in 1976 and discovered gas. After the physical formation of MTJA Office and Management in 1992 and the award of production sharing contracts in April 1994, the MTJA's Contractors/Operators have made significant progress in carrying out the petroleum exploration in their respective contract areas (Block A-18 and Blocks B-17 & C-19).

Since the signing of the PSCs in April 1994, a total of 5,800 line km of 2D seismic data and 2,366 square km (1,200 sq.km. from Western Flank in mid 2005) of 3D seismic data was acquired and interpreted by CTOC in Block A-18. CPOC acquired a total of 6,100 lines km of 2D seismic data and 1,938 square km of 3D seismic data in Blocks B-17 & C-19.

In year 2006 to 2007, CPOC acquired a total of 1,154 square km of 3D seismic data in Block B-17-01. Carigali Hess acquired a total of 1,560 square km of seismic data over the Carigali Hess and CSM combined full fold area in 2006.

In 2010, CPOC conducted 3D seismic surveys in the Eastern area covering 491.45 Sq.km. (full fold) and in the South Western Area covering 448.523 Sq.km. This is followed by exploration and appraisal drilling campaign starting in November 2010.

Exploration period for Blocks A-18, B-17 and C-19 has expired since 20 April 2002. Current contractors retain the Gas Holding Areas (GHA) in these blocks.

Those areas that were relinquished to MTJA have been merged as a new block in the JDA with an area of approximately 3,475 square kilometers (refer to the map below).

The Production Sharing Contract (PSC) for new Block B-17-01 was signed between MTJA and Contractors on 30 September 2004 for the right to explore and exploit petroleum in the JDA.

At the end of the exploration period under the PSC contract on September 2009, 7 exploration wells had been drilled and 7 Gas Holding Areas (Tanjung, Jinda, Andalas, Muda South East, Andalas East, Thanthong and Melati) were approved by MTJA with a total area of 512.9 sq.km. A three (3) year exploration extension period from 30 September 2009 to 29 September 2012 was approved by MTJA under the supplementary contract (No.1) of the PSC.
As end of November 2011, a total of sixty-nine (69) exploration and appraisal wells were drilled in the JDA: with thirty-seven (37) wells in Block A-18, and thirty-two (32) wells in Block B-17 / B-17-01.

Twenty-five (25) gas fields were declared in the JDA; 9 fields in Block A-18, namely, Cakerawala, Bulan, Suriya, Bumi, Bumi East, Senja, Samudra, Wira, and Samudra North; 9 fields in Block B-17, namely, Muda, Tapi, Jengka, Amarit, Mali, Jengka South, Jengka West, Jengka East and Muda South; and 7 fields in Block B-17-01, Tanjung, Jinda, Andalas, Muda South East, Andalas East, Thanthong and Melati. Some of these fields also have minor oil accumulations.

There are total of 162 development wells were drilled in JDA with 84 wells in Block A-18 and 78 wells in Block B-17.

As of the end of 2010, approximately 6.7 Trillion Standard Cubic Feet (TSCF) of 2P (Proved + Probable) gas reserves, exclusive of CO2, from twenty-five (25) fields have been discovered, together with 102 million barrels of 2P condensate and approximately 12 million barrels of 2P oil reserves.