NEW YORK ( TheStreet) -- Key Energy Services ( KEG), EV Energy Partners ( EVEP), Tesoro ( TSO) and Complete Production Services ( CPX) were top performers last week, while J.A. Solar ( JASO), Forest Oil ( FST) and Trina Solar ( TSL) eroded substantial value.Among the advancers the past week, Key Energy Services and EV Energy Partners topped the charts, gaining 10.9% and 10.8%, respectively. Tesoro rose 10.7% over the week, as Barclays Capital has raised the stock's rating to overweight from equal weight with a target price of $37 per share. Tesoro's Los Angeles refinery, temporarily shutdown, is ramping up towards normal operations. Complete Production Services rose 10.1% after J.P. Morgan rated the stock overweight with a target price of $42 per share. InterOil ( IOC) and SunPower ( SPWRA) gained 9.8% and 9.5%, respectively. Oil States International ( OIS) moved up 9.3% as CLSA has raised the stock's rating to buy from outperform. The brokerage has raised the target price to $95 per share from $94. Halliburton advanced 9% this week. G.T. Solar ( SOLR) rose 8.7% after receiving equipment orders worth $81.7 million from two customers in Asia. The orders were for equipment to produce poly-silicon used in the manufacture of solar cells. Among other movers, Patterson-UTI Energy ( PTEN) advanced 8.6%, RPC Inc ( RES) rose 7.7%, Superior Energy Services ( SPN) grew 7.7% and Seacor Holdings ( CKH) added 7.4%, Helmerich & Payne ( HP) moved up 7.4% last week after signing agreements to build and operate 12 FlexRigs, for delivery to eight exploration and production companies during fiscal 2012. Oceaneering International ( OII) gained 7.1% during the week. National-Oilwell Varco ( NOV) piled 6.8% on plans to acquire Ameron International, a manufacturer of fiberglass-composite pipes for a consideration of $85 per share in all an all-cash transaction valuing Ameron at $772 million, or 7.1 times its estimated 2012 EBITDA. Other winners included Whiting Petroleum ( WLL) up 6.6%, while Continental Resources ( CLR) gained 6.3%. Atlas Energy ( ATLS) rose 6.2%, whereas Anadarko Petroleum ( APC) and Schlumberger ( SLB) gained 6.1% each. Nexen ( NXY) improved 6.0%, Concho Resources ( CXO) piled 5.8% and YPF ( YPF) advanced 5.8%. J.A. Solar Holdings was the top lagger, shedding 8.2% as a drop in polysilicon prices could affect the company's competitiveness. The company has signed long-term purchase contracts with producers like GCL-Poly Energy Holdings and Wacker Chemie. Forest Oil Corporation shed 7.5%. Trina Solar declined 5.6% as Zacks has maintained a sell on the stock.