Marathon Oil has signed agreements to sell certain non-core assets to an undisclosed firm for $950m is a bid to strengthen its balance sheet amid plunging oil price.

Under the terms of the deal, the oil and natural gas producer will sell all of its upstream and midstream assets in Wyoming, US, for $870m. This excludes closing adjustments.

The upstream assets include waterflood developments in the Big Horn and Wind River basins, averaged 16,500 barrels of oil equivalent per day in first quarter 2016.

The assets consider for the sale also include the 570-mile Red Butte pipeline, which is the only export line in the area.

Marathon Oil said that the latest deals bring the total asset sales since August 2015 to approximately $1.3bn, exceeding the targeted range of $750m to $1bn.

Marathon Oil president and CEO Lee Tillman said: "Ongoing portfolio management continues to drive the simplification and concentration of our portfolio to lower risk, higher return US resource plays and support our 2016 objective of balance sheet protection."

Marathon Oil also has signed agreements to divest 10% stake in the outside-operated Shenandoah discovery in the Gulf of Mexico.

The firm will also sell operated natural gas assets in the Piceance basin in Colorado, and certain undeveloped acreage in West Texas for a total of $80m.

In February 2016, Marathon announced $1.4bn in 2016 capital spending program with focus on balance sheet protection and operational flexibility.