Oil major Royal Dutch Shell's earnings more than doubled in the second quarter, even when including a $1bn net charge due to impairments.Earnings, on a current cost of supplies (CCS) basis, surged to $5.1bn in the three months to June 30th, up from $2.4bn the year before, helped by higher liquids production volumes and prices.A strengthening Australian dollar on a deferred tax liability and higher contributions from manufacturing were also behind the better bottom line, the Anglo-Dutch group said.Earnings included a net charge of $979m.The upstream division recorded a net charge of $902m, as $1.23bn of divestment gains was offset by impairments of $1.94bn related to dry gas properties in the US. Downstream took a net charge of $76m.Excluding these so-called "identified items", second-quarter earnings totalled $6.1bn, up from $4.6bn the year before, an increase of 33%.The company said it would pay a second-quarter dividend of $0.47 a share, up 4% on last year."We are making progress with the priorities I set out at the start of 2014: to balance growth and returns by focusing on better financial performance, enhanced capital efficiency, and continued strong project delivery," said chief executive Ben van Beurden. "Our financial performance for the second quarter of 2014 was more robust than year-ago levels but I want to see stronger, more competitive results right across the company, particularly in Oil Products and North America resources plays. Improvement of financial performance in these two parts of the business will take time, but I see early momentum, which we must maintain."BC