Three oil and gas stocks are moving up in their overall rating this week, according to the Portfolio Grader database. Every one of these is graded an “A” (“strong buy”) or “B” overall (“buy”).

Chesapeake Midstream Partners (CHKM) is bumping up its rating from a C (“hold”) to a B (“buy”) this week. Chesapeake Midstream Partners owns, operates, develops, and acquires natural gas, natural gas liquids, and oil gathering systems, as well as other midstream energy assets in the United States. For more information, get Portfolio Grader’s complete analysis of CHKM stock.

This week, Miller Energy Resources, Inc. (MILL) is making solid headway. The company’s rating improves to an A (“strong buy”) from last week’s B (“buy”) rating. Miller Petroleum is an oil and gas exploration, production, and drilling firm. For more information, get Portfolio Grader’s complete analysis of MILL stock.

Panhandle Oil and Gas Inc. Class A (PHX) improves from a C to a B rating this week. Panhandle Oil and Gas explores for and develops oil and gas properties, and produces and sells oil and natural gas. The stock price has risen 12.1% over the past month, better than the 1.7% decrease the S&P 500 has seen over the same period of time. For more information, get Portfolio Grader’s complete analysis of PHX stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.