DUBAI, May 30 (Reuters) - Saudi Arabia may announce a landmark secondary share offering in oil giant Aramco later on Thursday, pending final approval from Crown Prince Mohammed bin Salman, people with knowledge of the matter said.

The landmark sale follows Aramco's record IPO nearly five years ago, as the kingdom pushes ahead plans to diversify its economy away from oil.

Below are key facts about Aramco:

HISTORY

Explorers from the Rockefeller family's Standard Oil Company struck oil in Saudi Arabia in 1938. The venture became known as the Arabia American Oil Company and crude oil production hit 500,000 barrels per day in 1949.

By 1980, the Saudi government had bought out all the original shareholders and owned 100% of the company. Eight years later, the Saudi Arabian Oil Company (Saudi Aramco) was officially established.

Aramco has fuelled decades of prosperity in Saudi Arabia. The kingdom is the de facto leader of the Organization of the Petroleum Exporting Countries, or OPEC, helping engineer price moves on world oil markets.

The crown prince, known as MbS, wants to diversify the Saudi economy away from oil. Announcing plans for an Aramco IPO in 2016, he said the kingdom must end its "oil addiction" to ensure it was no longer at the mercy of commodity price volatility.

OIL RESERVES AND OUTPUT

Aramco had 251.2 billion barrels of oil equivalent (boe) in 2023, larger than the combined reserves of ExxonMobil, Chevron, Shell, BP and TotalEnergies. That includes, as of end-December 2023, 191.35 billion barrels of crude and condensate and 33.8 billion boe of natural gas.

The oil giant produced just over 9 million barrels per day (mbpd) in April, according to secondary sources used by OPEC, down from an average of 9.6 mbpd in 2023. Its average upstream lifting cost was $3.19 per boe in 2023, with upstream capital expenditure averaging $6.3 per boe.

Just over two thirds of Aramco's crude oil was exported last year, as it shipped 6.6 mbpd, down from 7.1 mbpd in 2022. Asian customers bought 82% of Aramco's crude exports last year, up from 79% in 2022.

DOWNSTREAM

To diversify its oil business - and secure offtake of its crude - Aramco is expanding in refining and petrochemicals.

Last year, Aramco bought Valvoline Inc's global products business for $2.76 billion. It also began construction of several petrochemical complexes: a $7 billion one in South Korea with S-Oil, an $11.8 billion project in China, via HAPCO, a joint venture with North Huajin and Xincheng, and an $11 billion one through its joint venture with TotalEnergies in the kingdom.

It also bought a 10% stake in Chinese refiner Rongsheng Petrochemical for $3.4 billion. In 2020, it bought a majority stake in Saudi Basic Industries Corp (SABIC), one of the world's biggest petrochemical firms.

Aramco produces, refines and exports oil from Saudi Arabia, but also has refining operations across the globe. Aramco's U.S. oil refining subsidiary Motiva Enterprises owns the 640,000 bpd Port Arthur refinery in Texas, the largest in the United States.

It is looking to further expand its downstream business in "key high-growth geographies such as China, India and Southeast Asia," as well as other markets, it said in its annual report. Aramco had a net refining capacity of 4.1 mbpd last year.

GAS

Aramco aims to boost its gas production by 60% by 2030 from 2021 levels.

Last year, it brought online an expansion to its Hawiyah Gas Plant and began producing at its unconventional field in South Ghawar. It also continues work on its giant Jafurah field, expected to begin producing gas next year.

It also made its first investment abroad in liquefied natural gas, buying a minority stake in MidOcean Energy for $500 million, subject to approvals.

Aramco also discovered two new natural gas fields in the kingdom's Empty Quarter.

The company had 207.5 trillion cubic feet of gas reserves at the end of 2023. It produced 10.67 billion cubic feet of gas last year.

SCALE

The state-owned firm is one of the world's largest oil producers and top exporter, pumping nearly 10% of the world's supply. It is also among the globe's most profitable companies, raking in $27.3 billion in net profit in the first quarter, slightly more than oil majors ExxonMobil, Shell, Chevron and TotalEnergies made combined in the same quarter.

Last year, Aramco made an annual net profit of $121.3 billion, its second-highest on record after it hauled $161.1 billion in 2022.

In late 2019, Aramco raised $25.6 billion from its initial public offering, the world's biggest ever. It then sold more shares through an over-allotment option in January 2020 that boosted the IPO further to a total of $29.4 billion.

With more than 73,000 employees in 2023, Aramco has energy industry operations, research facilities and offices scattered across the globe, in Asia, Europe and the Americas. It has offices in Beijing, Houston, London, New Delhi, New York, Seoul, Shanghai, Singapore, Tokyo, and elsewhere.

(Reporting by Yousef Saba; Editing by Michael Georgy)