This week, 4 Energy Equipment & Services stocks are improving their overall rating on Portfolio Grader. Each of these rates an “A” (“strong buy”) or “B” overall (“buy”).

The rating of Core Laboratories NV (CLB) moves up this week, rising from a C to a B. Core Laboratories NV serves the oil and gas industry by providing it with proprietary and patented reservoir description, production enhancement, and reservoir management services. For more information, get Portfolio Grader’s complete analysis of CLB stock.

RPC, Inc. (RES) earns a B this week, jumping up from last week’s grade of C. RPC, Inc. provides specialized oilfield services and equipment to independent and major oilfield companies. The company also gets A’s in earnings surprise. For more information, get Portfolio Grader’s complete analysis of RES stock.

This is a strong week for Transocean Partners LLC (RIGP). The company’s rating climbs to B from the previous week’s C. The company also gets A’s in earnings revisions, earnings momentum, and return on equity. For more information, get Portfolio Grader’s complete analysis of RIGP stock.

North Atlantic Drilling Ltd. (NADL) boosts its rating from a C to a B this week. The company also gets A’s in earnings revisions, earnings surprise, earnings momentum, and free cash flow. For more information, get Portfolio Grader’s complete analysis of NADL 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.