* H1 results due Aug 31, after the market
* Net profit seen up 11.2 percent
* Order book seen reaching 5.5 billion euros
* Focus on signs of renewed investments in energy sector
MADRID, Aug 28 (Reuters) - Spanish engineering firm Tecnicas Reunidas is expected to post an 11.2 percent rise in first-half net profit on Monday as it shielded its margins from contract prices that fell with the drop in oil prices.
Net profit at the company, which specialises in the construction of onshore oil refineries, is seen rising 11.2 percent to 69.18 million euros ($99.34 million), according to a Reuters survey of seven analysts.
"We believe Tecnicas Reunidas has negotiated prices for new contracts as a way of protecting its margins versus last year despite the reduction in prices for the overall project cost," Ca Cheuvreux analysts said in a note.
Analysts are forecasting an order book of about 5.5 billion euros, an all-time high for the company, boosted by a major contract for the Al-Jubail refinery in Saudi Arabia awarded in June.
Tecnicas Reunidas' management will host a conference call on Sept 1 at 1400 GMT, where investors will focus on any signs of a reactivation of projects in the energy sector, where investments have tracked oil prices lower.
Following are the results of the survey in simple averages in millions of euros:
H109E H108 PERCENT CHANGE RANGE SALES 1,259 1,172 7.4 1,25-1,276 EBITDA 74.58 68.7 8.5 73.7-76.0 NET PROFIT 69.18 62.2 11.2 68.5-71.0
CONTRIBUTORS - Ahorro, Banesto, CA Cheuvreux, Venture Finanzas, Ibersecurities, Caja Madrid and one bank that asked not to be named. (Reporting by Tomas Gonzalez and Tracy Rucinski; Editing by Rupert Winchester) ($1=.6964 Euro)