This week, the overall grades of 17 oil and gas stocks are lower, according to the Portfolio Grader database. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

PDC Energy (PETD) is on the decline this week, earning a D (“sell”) after receiving a C (“hold”) last week. PDC is an oil and gas company with drilling and production operations in the Rocky Mountains, the Appalachian Basin, and Michigan. In Portfolio Grader’s specific subcategories of Earnings Revisions and Cash Flow, PETD also gets F’s. As of Nov. 29, 2013, 12.5% of outstanding PDC Energy shares were held short. To get an in-depth look at PETD, get Portfolio Grader’s complete analysis of PETD stock.

EOG Resources, Inc. (EOG) earns a D this week, moving down from last week’s grade of C. EOG Resources is in the business of the exploration, development, production, and marketing of natural gas and crude oil. The stock gets F’s in Earnings Growth, Earnings Momentum, and Margin Growth. The stock price has dropped 5.2% over the past month, worse than the 1.7% decrease the S&P 500 has seen over the same period of time. The stock currently has a trailing PE Ratio of 41.10. For a full analysis of EOG stock, visit Portfolio Grader.

Suncor Energy (SU) earns an F (“strong sell”) this week, moving down from last week’s grade of D (“sell”). Suncor Energy is an integrated energy company in Canada. The stock gets F’s in Earnings Momentum and Earnings Surprise. For more information, get Portfolio Grader’s complete analysis of SU stock.

Enbridge Energy Partners, L.P. Class A (EEP) experiences a ratings drop this week, going from last week’s D to an F. Enbridge Energy Partners transports crude oil and natural gas liquids to refineries in the midwestern United States and eastern Canada. The stock receives F’s in Earnings Growth, Earnings Revisions, and Earnings Surprise. Cash Flow and Sales Growth also get F’s. The trailing PE Ratio for the stock is 50.50. To get an in-depth look at EEP, get Portfolio Grader’s complete analysis of EEP stock.

PVR Partners, L.P. (PVR) gets weaker ratings this week as last week’s C drops to a D. Penn Virginia Resource Partners owns and operates a network of natural gas pipelines and processing plants which provide gathering, transportation, compression, processing, dehydration and related services to natural gas producers. The stock rates an F in Earnings Growth, Earnings Revisions, and Equity. Cash Flow, Margin Growth, and Sales Growth also get F’s. The stock has a trailing PE Ratio of 79.60. For a full analysis of PVR stock, visit Portfolio Grader.

This week, Midstates Petroleum Company, Inc.’s (MPO) rating worsens to an F from the company’s D rating a week ago. Macau Property Opportunities Fund Ltd. is a closed-end investment fund/investment trust. Its investment objective is to provide shareholders with an attractive total return, which is intended to comprise capital growth but with the potential for dividends over the medium to long term. The Fund aims … The stock gets F’s in Earnings Revisions and Cash Flow. To get an in-depth look at MPO, get Portfolio Grader’s complete analysis of MPO stock.

Green Plains Renewable Energy, Inc. (GPRE) earns a D this week, falling from last week’s grade of C. Green Plains Renewable Energy constructs and operates dry mill, fuel-grade ethanol production facilities. The stock gets F’s in Earnings Growth, Earnings Revisions, and Margin Growth. As of Nov. 29, 2013, 16.7% of outstanding Green Plains Renewable Energy, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of GPRE stock.

Chevron Corporation (CVX) is having a tough week. The company’s rating falls from a C to a D. Chevron gives management and technological support to international subsidiaries that operate petroleum, chemicals, mining, power generation, and energy services. The stock also gets an F in Sales Growth. To get an in-depth look at CVX, get Portfolio Grader’s complete analysis of CVX stock.

Slipping from a C to a D rating, ONEOK Partners, L.P. (OKS) takes a hit this week. ONEOK Partners is engaged in the gathering, processing, storage, and transportation of natural gas in the United States. The stock also gets an F in Sales Growth. For more information, get Portfolio Grader’s complete analysis of OKS stock.

This week, Continental Resources, Inc. (CLR) drops from a D to an F rating. Continental Resources explores for, develops, and produces oil and natural gas properties in the United States. The stock gets F’s in Earnings Growth, Earnings Momentum, Cash Flow, and Sales Growth. For a full analysis of CLR stock, visit Portfolio Grader.

The rating of Teekay Corporation (TK) slips from a C to a D. Teekay is a provider of international crude oil and petroleum product transportation services. The stock gets F’s in Earnings Momentum, Earnings Revisions, and Earnings Surprise. Equity and Cash Flow also get F’s. To get an in-depth look at TK, get Portfolio Grader’s complete analysis of TK stock.

Frontline’s (FRO) rating weakens this week, dropping to an F versus last week’s D. Frontline owns a fleet of very large crude carriers and Suezmax tankers that transport crude oil and oil products between ports. In Earnings Revisions, Equity, Cash Flow, and Sales Growth the stock gets F’s. As of Nov. 29, 2013, 12.9% of outstanding Frontline shares were held short. For a full analysis of FRO stock, visit Portfolio Grader.

Endeavour International Corporation (END) earns an F this week, moving down from last week’s grade of D. Endeavour International is an international oil and gas exploration and production company that acquires, explores, and develops energy reserves. The stock gets F’s in Equity and Cash Flow. As of Nov. 29, 2013, 20.2% of outstanding Endeavour International Corporation shares were held short. For more information, get Portfolio Grader’s complete analysis of END stock.

This is a rough week for North European Oil Royalty Trust (NRT). The company’s rating falls to F from the previous week’s D. North European Oil Royalty Trust is involved in gas and oil production, and it holds overriding royalty rights in certain concessions or leases in the Federal Republic of Germany. The stock also rates an F in Sales Growth. For a full analysis of NRT stock, visit Portfolio Grader.

The rating of SandRidge Energy, Inc. (SD) declines this week from a D to an F. SandRidge Energy explores and produces natural gas and crude oil. The stock receives F’s in Earnings Growth, Earnings Momentum, and Equity. Cash Flow and Margin Growth also get F’s. As of Nov. 29, 2013, 12.8% of outstanding SandRidge Energy, Inc. shares were held short. For more information, get Portfolio Grader’s complete analysis of SD stock.

Slipping from a D to an F rating, Gevo (GEVO) takes a hit this week. Gevo operates as a technology development company for biobutanol. The stock gets F’s in Equity, Cash Flow, and Sales Growth. As of Nov. 29, 2013, 17.1% of outstanding Gevo shares were held short. To get an in-depth look at GEVO, get Portfolio Grader’s complete analysis of GEVO stock.

This week, Teekay Offshore Partners L.P.’s (TOO) rating worsens to a D from the company’s C rating a week ago. Teekay Offshore Partners LP provides marine transportation and storage services to the offshore oil industry. The stock also gets an F in Sales Growth. For a full analysis of TOO stock, visit Portfolio Grader.

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.