(Adds new deferrals of August cargoes.) By Sherry Su Of DOW JONES NEWSWIRES LONDON (Dow Jones)--Supply of North Sea Forties crude is expected to tighten further as more deferrals of cargoes occurred due to unstable production, traders said Friday. Nexen Inc.'s (NXY) two cargoes for July loading have been deferred to August. The cargoes numbered F0722 was deferred to August 2-4 from July 22-24, and the F0727 cargo was deferred to August 1-3 from July 27-29, traders said. ConocoPhillips's (COP) F0729 cargo for July 29-31 loading was dropped, they said. Meanwhile, another three cargoes for August were also deferred, bringing total deferrals of August cargoes to eight. It remains to be seen if there will be more deferrals in the short term. Technical glitches and planned maintenance at some fields and pipeline contributed to these deferrals, traders said. Production at the 200,000-barrel-a-day Buzzard field, the largest in Forties system, hasn't been very stable recently. "Buzzard had a couple minor hiccups over the last week or so, but they were minor and production is up to full rates now," said spokesman Tim Chatten of operator Nexen. There was also a technical glitch on the Forties Pipeline System, operated by BP PLC (BP). Earlier this week, Nexen shut its Scott platform in the North Sea due to "a valve failure on the Forties pipeline system," the company said Thursday in its second-quarter earnings statement. Parcel No. Original Dates Revised Dates Volume(Bbl) Lifters F0722 Jul 22-24 Aug 2-4 600,000 Nexen F0727 Jul 27-29 Aug 1-3 600,000 Nexen F0729 Jul 29-31 dropped 600,000 ConocoPhillips F0802 Aug 4-6 Aug 7-9 600,000 ConocoPhillips F0804 Aug 7-9 Aug 8-10 600,000 Nexen F0806 Aug 10-12 Aug 13-15 600,000 Statoil F0808 Aug 13-15 Aug 16-18 600,000 Nexen F0810 Aug 16-18 Aug 17-19 600,000 Petro-Canada F0813 Aug 20-22 Aug 21-23 600,000 Nexen F0816 Aug 24-26 Aug 26-28 600,000 Nexen F0818 Aug 26-28 Aug 27-29 600,000 ConocoPhillips -By Sherry Su, Dow Jones Newswires; +44(0)20-7842-9329; [email protected] (END) Dow Jones Newswires July 16, 2010 11:12 ET (15:12 GMT)