Mr Dave O'Reilly, the Irishman behind Chevron's revived takeover bid for nearest rival Texaco, has spent his entire career with the US number two oil company, having risen rapidly through the ranks since he joined the company in 1968.

Originally from Ballsbridge in Dublin, Mr O'Reilly went to school in Blackrock before studying chemical engineering in UCD. He joined Chevron as a graduate engineer from UCD.

Mr O'Reilly worked in a variety of the company's plants in New Jersey, Utah and Texas before being posted to Chevron's headquarters in San Francisco in the early 1990s.

The charismatic Irishman, who began his career as a process engineer, was handpicked to succeed the older, Mr Ken Derr last year.

Despite his heavy workload, Mr O'Reilly is still a regular visitor to Ireland and has delivered a number of talks at the UCD engineering faculty over the years. A keen golfer, he is married with two daughters. He recently became a grandfather.

The revived deal would place the Dublin man at the head of the merged organisation, but keep Texaco chairman Mr Peter Bijur in top management, according to sources. A similar deal failed 16 months ago when Texaco reportedly balked over Mr O'Reilly leading a combined company.

Analysts give Mr O'Reilly much of the credit for reviving the deal. Since taking office this year, O'Reilly has expanded Chevron's reach and showed the world that even Big Oil can be technological savvy, all the while keeping his sights on his closest rival.

Since the failed deal last year, the company has focused on its operations overseas, such as in West Africa, Argentina and the Caspian Sea. It divested less profitable US assets, met cost-cutting targets of $500 million (€589 million), and mostly deserted San Francisco skyscrapers to more modest offices.

Located in the heart of the high-tech industry, Chevron joined the fray, leading the industry in initiatives to utilise the Internet for energy-related commerce. It even created a venture capitalist division to back new high-tech companies, that may or may not be related to the oil business.

After Chevron's larger rivals took over smaller companies - Exxon with Mobil and BP Amoco with Atlantic Richfield - a sizeable merger was seen as the only way San Francisco-based Chevron could compete with the new supermajors and increase its market share and stock price.