Nakajo Oil and Gas Field

We believe the mission of Japanese energy companies is to secure energy sources in Japan.
We aim to secure a stable energy supply by continuing to explore promising areas of Japan.

Onshore Aomori
Onshore Akita
Nakajo Oil and Gas Field
Nishi Kyushu-oki

Nakajo Oil and Gas Field

The onshore Nakajo oil and gas field in Niigata Prefecture is JX's one and only exploration and production base in Japan.

Our target is to ensure a continuous supply of natural gas as fuel and chemical material to customers including industries and local communities. Discovered in 1957, the Nakajo oil and gas field is composed of three different types of hydrocarbon accumulations: non-associated natural gas, natural gas dissolved in water, and black oil. Because it is rare to find three different kinds of reservoirs in such proximity to each other in Japan, the field serves as a "textbook"-like facility to train engineers who will work overseas.

The Nakajo oil and gas field has produced more than five billion standard cubic meters of natural gas since the first production in 1959, and continues to yield a significant volume of gas and crude oil.

In addition, crude iodine is extracted from kansui, the water in which natural gas is dissolved, and exported as a raw material for the production of pharmaceuticals and chemicals.

Crude Oil and Natural Gas

Natural gas produced from underground reservoirs is gathered at a central processing plant. The gas is processed to sales specifications and delivered to regional customers through pipelines. Crude oil associated with the natural gas is separated, processed and stored in storage tanks, and then delivered to customers in tankers.


Uses of iodine

Iodine has utilized in a broad range of spheres.
Its main areas of use include medical applications such as X-ray contrast media and gargles, sterilizers, fungicides, feed additives, photo-sensitizers and polarizing films for liquid crystal displays. It is also an element necessary for human existence.

X-ray contrast media 22% Sterilizers and fungicides 17% Industrial catalysts 15% Feed additives 9% Pharmaceuticals 9% Stabilizers 8% Added salt 6% Herbicides 4% Photographic chemicals 2% Other uses 8%

Iodine manufacturing

We manufacture iodine using the blow-out method, which takes advantage of iodine's tendency to vaporize easily.

Process outline

An oxidant is added to kansui that was separated from natural gas to extricate iodine.

  1. 1.The iodine is diffused into the air with a blower. It is then reduced with an absorbing agent and turned into an absorbed solution.
  2. 2.The solution is crystallized and impurities are removed through heating and melting. It then undergoes cooling-solidification/crushing before being stored in drums as the final product.

Product specifications

  • Purity: More than 99.7%
  • Non-Volatile Materials: Less than 0.05%
  • Sulfate: Less than 0.02%
  • Chlorine/Bromine: Less than 0.005%

Company History

December 1956 Established Nakajo Oil Field Exploration Office (renamed the Nakajo Oil and Gas Field in 1959)
March 1957 Discovered water-dissolved gas field (R-1)
August 1961 Discovered non-associated gas field (central district, NK-1)
August 1965 Discovered non-associated gas field (northern district, NK-13)
November 1966 Commenced supply of kansui as an iodine raw material (iodine production as a directly controlled business commenced in January 1996)
1969 Natural gas production reached 1 million m3/D and crude oil production reached 150 KL/D
January 1978 Discovered Shiunji Field (NK-53)
September 1998 Acquired ISO 9002 certification (the first certification of an oil and natural gas mine in Japan; upgraded to ISO 9001 in 2001)

Recent development well drilling

July 2018 Drilling of N23-5, 6, 7 (water dissolved gas field, southern district)

Exploration Blocks

Sanriku-oki, Erimo-okiExploration

Project Company JX Nippon Oil & Gas Exploration Corporation
Interest 50%〜100%

Shikoku-oki, Nishi Kyushu-okiExploration

Project Company JX Nippon Oil & Gas Exploration Corporation
Interest 100%

Onshore BlockExploration

Project Company JX Nippon Oil & Gas Exploration Corporation
Interest 100%