"You aren't starting another of your adventures are you? Why don't we retire?" asks Snowy at the start of the story. Was this a sign of Hergé's exhaustion with the series, hence the recycling of an abandoned story? If so it may explain some of the problems. The result is that the final version is an awkward hybrid of the political commentary and comedy of the early Adventures with the pulp escapist action of the 1940s tales. It doesn't always conceal the joins very well, as seen most obviously with Captain Haddock's involvement. At the start, he phones up Tintin to explain he's been mobilised because of the international situation, then he suddenly appears towards the end to rescue Tintin. Rather than give an explanation for his arrival, this is instead turned into a running gag whereby every time he starts to tell Tintin something happens to interrupt him. Calculus is notably absent from the story, just sending a letter at the end explaining his experiments which have now found an antidote for Formula Fourteen. These are awkward inclusions, doubtlessly intended to match up to the current cast status quo, but it feels odd given the wider backdrop.
One of the dated aspects of the story that hasn't been filtered out in subsequent revisions is the deteriorating international situation with widespread expectations of war and the armed forces being mobilised. This aspect is noted repeatedly in the first half of the story but then the first time Tintin is able to access the news in the second half he discovers that tensions have eased with an international summit. The original serialisation of the story began in late September 1939, just four weeks after Germany invaded Poland, starting the European theatre of the Second World War, and barely eleven days after Russia also invaded. During the eight months of the adventure's serialisation there was an uneasy calm on the Western Front, known as the "Phoney War", in which neither of Belgium's big neighbours undertook significant land action against the other. In such circumstances the prospect of war by economic sabotage rather than direct military action would have been highly topical. And the presence of an agent with a German name, Dr Müller (previously seen in The Black Island), would have reflected the audience's fears - as well as making it impossible to continue the story once the Germans had occupied the country. However, by the late 1940s the world was a very different place with the immediate threat of war receding and so this aspect of the tale is downplayed with the contamination of the petrol ceasing and the story shifting to one of rival oil companies intervening in the politics of the Middle East to secure concessions. Only at the end of the story is the original contamination addresses, with Müller revealed to be an agent of an unnamed "major foreign power" - perhaps the 1950 audience would have interpreted this as meaning the Soviet Union and Müller himself as being from the by-now established East Germany.
The contamination itself drives a lot of the early humour as petrol spontaneously explodes, causing especial problems for Thompson and Thomson who proceed to investigate the most prominent repair company with hilarious results. Once in the Middle East they spend most of the story driving around the desert in a jeep, encountering trouble with mirages and people who aren't mirages, sandstorms and following their own tracks. Such is their usefulness that when Tintin secures their release for crashing into a mosque, he insists that they are not allowed to leave the Emir's palace as they will not be helpful. Despite this they do show up for the final showdown where they discover pills disguised as aspirin and ingest them - only to find it's the chemical used to contaminate the petrol and it results in their hair rapidly growing in multiple colours. This story features the Thom(p)sons more than most, even giving them their only cover appearance, and it shows how their presence in the stories was growing until they were displaced by the arrival of Haddock, thus again highlighting the story's convoluted development.
The current version of the story sets the main action in Khemed, a fictional Arab kingdom where the Emir Ben Kalish Ezab is facing a rebellion by Sheik Bab El Ehr. Initially this seems to be the backdrop for a story of sabotage but then it appears that Bab El Ehr is a puppet of Skoil Petroleum who are trying to replace their rivals, Arabex, as the holders of the oil concession in the country. But Müller at other times seems to be operating independently of Bab El Ehr, trying to stir up tensions between the rival Arabs to secure the concession for Skoil. This mix of corporate saboteur and foreign agent again reflects a tale of two halves but just muddies the waters as to Müller's actual motivations. It leads to the main slapstick in the latter part of the story as the Emir's spoilt brat son Abdullah is kidnapped and Tintin goes to rescue him with the help of returning trader Oliveira da Figueira. But Abdullah treats the whole thing as a game, often disrupting the rescue and thus he's eventually taken by Müller in flight through the desert, with Tintin and the now-arrived Haddock in pursuit. Abdullah is a very irritating child and it's little surprise that even Tintin loses his temper.
The setting of Khemed means that the tale now takes place in a fictional generic Arab oil state, which actually makes more sense than British Palestine. What little we see of the country is generally a respectful portrayal, though the Emir is implied to dispense brutal justice to the point that Müller prefers to attempt suicide instead of being arrested. When this fails, it takes Tintin to insist upon a trial, with the Emir muttering "How you Westerners complicate things! We men of the East are far more expeditious!" Even without the colonial setting (although where an Emirate was supposed to be in the mandate is a question that the revision thankfully sweeps away) there's still a sense of western European superiority that was notable in the earliest tales, showing something of a reversion to those days.
Ultimately this is a mess of a story, with each half trying to remain true to whichever end of the 1940s it originally appeared in. Thus what starts out as a tale of international espionage as preparation for war turns into a tale of corporate struggles, with character motivations shifting all over the place. The final revision hasn't cleaned up the confusion and so it leaves this awkward hodgepodge that ranges all over the place. It's a sign of how trying to pick up and finish off incomplete stories isn't always the best course of action.