Kashagan has become an infamous name in the world of oil and gas. Why? Well Kashagan is the world's largest oil discovery in the past four decades and, as you would expect, oil companies are fighting to get their hands on the discovery.

But Kashagan has not been an easy 'drill and produce' field. The project is huge -- so huge in fact that is taking a consortium of the world's largest oil companies to develop it.

The project is currently being led by Italy's Eni (NYSE:E), France's Total (NYSE:TOT), Anglo-Dutch Royal Dutch Shell (NYSE:RDS-B), and the world's largest publicly traded oil company, ExxonMobil (NYSE:XOM).

Kashagan's infamy stems from the fact that the field has become one of the most complex oil projects ever undertaken.

In total, the project is expected to cost $136 billion over its lifetime, which is about 140% more than originally planned. And the cost could be about to jump again.

The project commenced production late last year, but a gas leak rapidly shut production down. It is believed that the gas leak was caused by high levels of sulphide, which have caused hairline fractures in the project's pipelines.

Now, it is believed that these pipelines will have to be replaced with a different metal alloy, an alloy that is expected to cost 10 to 15 times more than the current pipeline system.

Losing patience
In an attempt to stop the delays and get the project back on track, ExxonMobil is now in line to take over as the field's operator.

Italy's Eni is currently the project's operator, a job it was given back during 2001. But since taking over, Eni has lost its sole right to run and control the project. Unsurprising, considering the crippling cost overruns and major delays the project has now run into.

Indeed, it is estimated that after the pipeline replacements, the project won't restart until early 2016 -- a far cry from the initial estimates of later this year, which were originally given following the most recent disaster.

Talks are currently ongoing, but Exxon could be appointed as soon as the end of June and hopefully the world's largest oil company will be able to put its skills, experience, and global reputation to work, getting things in place to start up the project as fast as possible while minimizing additional cost overruns.

But even with Exxon running the show it is likely that the project will take up to three years from start-up to reach its targeted plateau output of 370,00 barrels per day.

It will be worth it
If Exxon can sort things out, the start-up of Kashagan will be a boon for the oil and gas industry.

It is expected that 38 billion barrels of oil are contained within the Kashagan field -- in other words, with oil trading at $109 per barrel, the reserves are in theory worth $4.2 trillion. Just to put that into some perspective, Exxon owns around 17% of the project, so its stake is arguably worth around $700 billion over the lifetime of the field, nearly double the company's current market capitalization.

Foolish summary
Overall, Kashagan has been a trouble child for the oil and gas industry, but in the end it should pay off. Eni has been in charge for the past decade and things have not gone to plan. Now, ExxonMobil is in charge; the world's largest oil company will be able to use its size and connections to drive Kashagan forward and ramp up production.