Pioneer Natural Resources Co. said Thursday that it is trying to sell its properties in the Barnett shale region of Texas to reduce debt and focus operations on more productive areas.

Shares of Pioneer rose $4.12, or 4.3 percent, to $100.14 in afternoon trading.

The company hopes to complete the divestiture in the first quarter of 2013.

Pioneer said it will shift spending to assets in the Spraberry and Wolfcamp shale fields of west Texas and the Eagle Ford shale field of east Texas.

The Dallas company began operating in the Barnett shale in 2007 and has about 155,000 acres, producing the equivalent of about 7,000 barrels of oil per day. Of that, 55 percent is oil and natural gas liquids and 45 percent is so-called dry gas.

Pioneer hired RBC Richardson Barr to market the properties.