PetroChina Co, Asia’s largest oil and gas producer, said on Thursday first half 2019 net profit rose 3.6% from a year earlier, driven up by increasing crude oil and natural gas sales.

“Looking forward, we will focus more on the Belt & Road Initiative, such as Russia, Central Asian and Middle East countries…and will increase the natural gas percentage in our overseas portfolio to optimise the asset structure,” PetroChina Executive Director and President Hou Qijun said.

For the first six months of 2019, the company earned 28.42 billion yuan ($4.01 billion), up from 27.44 trillion for the same period last year, PetroChina said in a filing to the Hong Kong stock exchange. Total revenue for the state-backed company was 1.12 trillion yuan, up 6.8% from the same period in 2018.

Profit for the April to June quarter was 18.17 billion yuan, the highest since the third quarter last year, according to calculations by Reuters based on the earnings filing. That compares with 16.94 billion yuan in the same period a year earlier and 10.25 billion yuan in the first quarter of this year.

Over the first six months of 2019, PetroChina produced a total of 451.9 million barrels, or 2.5 million barrels per day, up 3.2% from the same period in 2018. While natural gas output increased 9.7% to 1.96 trillion cubic feet, or 55.5 billion cubic metres.

It also reported a 3.1% increase in crude oil throughput at its refineries to 597.4 million barrels, or 3.3 million barrels per day.

With Beijing’s push to boost domestic energy production, PetroChina invested 12.27 billion yuan in upstream exploration in the first half of 2019, 14% more compared to the same period last year.

Chinese energy companies have said they plan to raise spending on domestic drilling this year to the highest since 2016 to safeguard the country’s energy security.

PetroChina earlier this month started to drill its first shale oil well in China’s southwestern province of Sichuan and vowed to double natural gas output in the region to 50 billion cubic metres by 2025.

“In the second half of the year, the company will vigorously implement centralised exploration in key regions…deepen the stable production of old oilfields…and focus on shale gas production to increase production,” it said in the statement.

The company also addressed the risk of an economic downturn, excessive domestic oil refining capacity and the restructuring of oil and gas pipelines system.