What a difference a week makes. AJ Lucas (ASX: AJL) has gone from last week’s biggest gainer to this morning’s 2nd biggest loser.

Overnight, a shale gas site operated by Caudrilla (in which AJ Lucas has a substantial stake) caused a major tremor.

The government-run Oil and Gas Authority has since ordered the company to suspend fracking pending an investigation.

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Caudrilla said this was a minor setback.

“Caudrilla notes that minor seismic events are not an uncommon by-product of the HF process,” the company said.

It noted this event was an average ground motion of 5mm per second, one third of the limit permitted for construction projects.

But for the locals, all they cared about was that their houses were shaken. Locals asserted that this was the largest fracking-induced earthquake to have happened in the UK.

The Oil and Gas Authority will now consider the appropriateness of the company’s Hydraulic Fracture Plan.

AJ Lucas shareholders sent the stock down 36 per cent. It is the 2nd biggest loser this morning after Ultracharge (ASX:UTR).

In other ASX energy news today…

Shares in junior explorer Warrego Energy (ASX: WGO) rocketed higher after the company announced a significant gas discovery in the North Perth Basin, where WGO is drilling as part of a 50/50 joint venture project with Strike Energy (ASX: STX).

“This exciting discovery has exceeded our pre-drill expectations for the Kingia and substantially upgraded our view of the West Erregulla gas fields as a whole,” CEO Dennis Donald said. Shares in WGO rose more than 50 per cent in morning trade to 28 cents.

Key Petroleum (ASX: KEY) has jumped after identifying new prospects at its Cooper Basin acreage. Key also said one of its projects, Tanbar, is back on track. The access track into Tanbar has been repaired after flood damage and an agreement with the landowner is about to be finalised.

Yesterday we reported Byron Energy (ASX: BYE) surged 28 per cent after encountering hydrocarbons at a well it had only begun drilling three weeks.

This morning, it gained another 14 per cent after it  said casing would be set in the well at its 10,890 measured depth drilled thus far. The company said it was to ensure its protection and optimise the cement job across the entire pay interval. Prior to setting casing the company will conduct logging to evaluate the pay interval.

At Stockhead, we tell it like it is. While Warrego Energy is a Stockhead advertiser, it did not sponsor this article.