Lagos pipeline blast

Once again, people have been killed in an oil pipeline explosion. There's been fuel shortage in Lagos recently, so people did what they always do, steal from a pipeline. And someone probably did something to spark an explosion as always inevitably happens. This incident begs the same two question which always arise: why does the world's sixth largest exporter of oil have fuel shortage? And why do people keep stealing from oil pipelines given the well documented tragedies that always happen?