Al-Humaidhi resigned after continuing criticism over his time as Finance Minister, which parliament has been investigating after allegations of financial irregularities.
“We were quite happy that he had been made oil minister because he had a good reputation and we needed the stability after four months with nobody in charge,” says one Kuwait-based oil executive.
“Now with Al-Humaidhi gone, we are back to square one and no one knows exactly what is going to happen next.”
Al-Humaidhi was appointed oil minister after a cabinet reshuffle in early November.
The post had been vacant since the resignation of Sheikh Ali al-Jarrah al-Sabah in May. Al-Humaidhi resigned after pressure from lawmakers who had been investigating financial irregularities.
In late October, they issued a grilling request against him, which the government circumvented by making him oil minister in the reshuffle.
However, MPs argued that this went against the spirit of the constitution and threatened to continue their interrogation efforts against him, ultimately forcing him to resign.
The affair is already seen as a political victory for the National Assembly (parliament) over the government, which seems to be powerless to prevent fierce criticism of its ministers.
It is also another backward step for the oil and gas sector, which has been hit by a series of negative events in 2007.
These include accusations over the true level of proven oil reserves, doubts over its gas claims and a dispute with Saudi Arabia over the use of land for its new refinery project.
Electricity & Water Minister Mohammed al-Olaim takes over as Acting Oil Minister.
It is still unclear when the government will appoint a replacement minister for Al-Humaidhi.