For the current week, the overall ratings of 15 oil and gas stocks are worse, according to the Portfolio Graderdatabase. Each of these rates a “D” (“sell”) or “F” overall (“strong sell”).

Crescent Point Energy Corp.’s (CPG) rating falls this week to an F (“strong sell”), down from last week’s D (“sell”). In Portfolio Grader’s specific subcategories of Earnings Revisions, Earnings Surprise, Cash Flow and Margin Growth, CPG also gets F’s. The stock currently has a trailing PE Ratio of 254.70. For more information, get Portfolio Grader’s complete analysis of CPG stock.

Golar LNG Partners’ (GMLP) rating falls to a D (“sell”) this week, down from C (“hold”) the week prior. Golar LNG Partners owns floating storage and regasification units and liquefied natural gas carriers. To get an in-depth look at GMLP, get Portfolio Grader’s complete analysis of GMLP stock.

This week, Kinder Morgan, Inc. Class P’s (KMI) rating worsens to an F from the company’s D rating a week ago. Kinder Morgan Energy Partners is a pipeline transportation and energy storage company. The stock price has fallen 10.6% over the past month, worse than the 1.7% decrease the S&P 500 has seen over the same period of time. The trailing PE Ratio for the stock is 28.10. For a full analysis of KMI stock, visit Portfolio Grader.

This is a rough week for Cosan Limited Class A (CZZ). The company’s rating falls to F from the previous week’s D. Cosan is a global ethanol and sugar company in terms of production with low-cost, large-scale and integrated operations in Brazil. The stock gets F’s in Cash Flow and Margin Growth. For more information, get Portfolio Grader’s complete analysis of CZZ stock.

The rating of Goodrich Petroleum Corporation (GDP) slips from a C to a D. Goodrich Petroleum explores, develops, produces, and acquires oil and natural gas properties. The stock receives F’s in Earnings Growth, Earnings Revisions, Equity and Cash Flow. Share prices fell 18.5% over the past month. As of Feb. 28, 2014, 20.6% of outstanding Goodrich Petroleum Corporation shares were held short. In the past week, the volume of trades plummeted to half the previous rate. To get an in-depth look at GDP, get Portfolio Grader’s complete analysis of GDP stock.

EXCO Resources, Inc. (XCO) is having a tough week. The company’s rating falls from a D to an F. EXCO Resources is an oil and natural gas company involved in the exploration, exploitation, development and production of onshore North American oil and natural gas properties. The stock gets F’s in Earnings Surprise, Equity and Cash Flow. Wall Street appears to agree with the stock downgrade, with share prices dropping 5.1% over the past month. As of Feb. 28, 2014, 12.4% of outstanding EXCO Resources, Inc. shares were held short. The stock has a trailing PE Ratio of 46.00. For more information, get Portfolio Grader’s complete analysis of XCO stock.

This week, Calumet Specialty Products Partners, L.P. (CLMT) drops from a D to an F rating. Calumet Specialty Products produces hydrocarbon products in North America. The stock gets F’s in Earnings Growth, Earnings Momentum and Earnings Revisions. Cash Flow and Margin Growth also get F’s. To get an in-depth look at CLMT, get Portfolio Grader’s complete analysis of CLMT stock.

The rating of Chevron Corporation (CVX) slips from a D to an F. Chevron is an integrated energy company with operations in countries located around the world. For a full analysis of CVX stock, visit Portfolio Grader.

This week, Plains All American Pipeline, L.P.’s (PAA) rating worsens to a D from the company’s C rating a week ago. Plains All American Pipeline is involved in interstate and intrastate crude oil pipeline transportation and crude oil terminalling storage activities. For more information, get Portfolio Grader’s complete analysis of PAA stock.

TransCanada Corporation (TRP) experiences a ratings drop this week, going from last week’s D to an F. TransCanada develops and operates energy infrastructures, including natural gas pipelines. The stock’s trailing PE Ratio is 37.50. To get an in-depth look at TRP, get Portfolio Grader’s complete analysis of TRP stock.

Enbridge’s (ENB) rating weakens this week, dropping to an F versus last week’s D. Enbridge is in the business of transportation and distribution of crude oil and natural gas primarily in Canada and the United States. The stock gets F’s in Earnings Growth, Earnings Momentum and Cash Flow. The stock currently has a trailing PE Ratio of 75.90. For a full analysis of ENB stock, visit Portfolio Grader.

Slipping from a C to a D rating, StealthGas (GASS) takes a hit this week. StealthGas offers marine transport services for liquefied petroleum gas producers and users. In Earnings Growth, Earnings Revisions, Earnings Surprise and Cash Flow the stock gets F’s. For more information, get Portfolio Grader’s complete analysis of GASS stock.

Ultrapar Participacoes S.A. Sponsored ADR (UGP) earns an F this week, moving down from last week’s grade of D. Ultrapar Holdings operates in the segment of liquefied petroleum gas (LPG) distribution, light fuel & lubricant distribution, and related business in Southern and Southeastern Brazil, production and marketing of chemicals, and provision of integrated logistics solution services for special bulk cargo. To get an in-depth look at UGP, get Portfolio Grader’s complete analysis of UGP stock.

Gevo (GEVO) earns an F this week, falling from last week’s grade of D. Gevo operates as a technology development company for biobutanol. The stock gets F’s in Equity, Cash Flow and Sales Growth. Shares of the stock have been trading at an exceptionally rapid pace, up fourfold from the week prior. For a full analysis of GEVO stock, visit Portfolio Grader.

PDC Energy (PETD) gets weaker ratings this week as last week’s C drops to a D. PDC Energy is an oil and gas company with drilling and production operations in the Rocky Mountains, the Appalachian Basin and Michigan. The stock gets F’s in Earnings Revisions and Cash Flow. As of Feb. 28, 2014, 11.3% of outstanding PDC Energy shares were held short. For more information, get Portfolio Grader’s complete analysis of PETD 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.