* Says pipeline leak was caused by oil theft
* Tracking data suggests delays of at least 2 weeks (Adds quote, detail on delays)
DAKAR, March 25 (Reuters) - Royal Dutch Shell saidon Tuesday it had declared force majeure on exports of theForcados oil grade due to a pipeline leak caused by oil theft.
OPEC member Nigeria is Africa's top oil producer although itrarely pumps at full capacity due to rampant oil theft, costingthe country billions of dollars.
"Unknown persons had installed a crude theft point on theline in water depth of about eight metres," Shell said in thestatement.
A "slight sheen" was visible near the line, it added.
The firm said on March 14 that it had suspended third-partyexports of Nigeria's Forcados grade.
Ship-tracking data showed that one Suezmax tanker has beenin the vicinity of the Forcados terminal since March 9,indicating a waiting period of at least two weeks.
Shell did not give a timeframe for repairs, adding only thatit was seeking to reopen the export line as soon as possible. (Reporting by Emma Farge; editing by Jason Neely)