(Adds analyst, shares, details) May 12 (Reuters) - SBM Offshore reported a 15% drop in first-quarter revenues as its turnkey business continued to suffer from tough energy markets, sending it shares as much as 4.6% lower on Wednesday. The Dutch-based company’s turnkey division builds and sells floating production and storage vessels to oil and gas firms and so is highly sensitive to their investment plans. These customers slashed spending last year as oil demand plunged in the pandemic, but a recovery in energy prices has since buoyed their earnings. “We believe SBM’s trading update was reasonable, albeit revenues ended (...) lower than we could expect based on its 2021 guidance of $2.6 billion,” ING analyst Quirijn Mulder said in a note to clients. SBM pointed to four floating production storage and offloading (FPSO) units under construction, saying they would contribute to earnings in future as the vessels commence production. “Despite the continuing challenging environment due to the pandemic, our operating performance was strong and our major projects under construction are progressing as expected,” Chief Executive Bruno Chabas said in a statement. First-quarter revenues came in at $513 million, against $607 million a year earlier, including a 24% drop in the turnkey business and a 12% decline in the lease and operate division, which runs and leases vessels later sold to customers after an initial lease period and relies on multi-year contracts. For the full year, SBM expects the lease and operate business to generate around $1.6 billion in revenues and turnkey operations to bring in about $1 billion. “The outlook for this niche within the oil services industry is excellent with high likelihood of more contracts arriving,” Mulder said, adding the deep water projects that SBM works on offer good prospects for high returns for oil companies. (Reporting by Juliette Portala. Editing by Mark Potter)