Petrochina (NYSE:PTR) is the largest oil and gas company in Asia and fifth largest in the world. Capital expenditures increased 27.6% for the 24 months ended December 31, 2012. Onshore operations in Bohai Bay and Daquing oil fields and the construction of Zhongwei-Guiyang pipeline remain focal points with PTR’s expenditure into each business segment domestically. With acquisitions and developments in Canada, Iraq and other offshore oil and gas fields, capital expenditure will increase to sustain these exploration projects. Alongside the Depreciation & Amortization of the capital assets required for large scale oil companies, depletion of their current reserves is a cost which will eventually be recognised unless attended to.