Australian law firms Allens Arthur Robinson and Mallesons Stephen Jaques are taking lead roles in Royal Dutch Shell and Petrochina’s $3 billion joint takeover bid for Australian coal seam gas company Arrow Energy Ltd. announced earlier this week.

Shell has long been regarded as a natural suitor for Arrow. Its appearance alongside Chinese state oil giant Petrochina is more of a surprise though, The Wall Street Journal reports, which suggests that ongoing cost-cutting efforts at Shell may have encouraged a joint approach.