Combining keyword phrases

[drillingtrader]

http://www.drillingtrader.com

I am wanting to combine;

oilfield classifieds
drilling classifieds
oilfield services classifieds

A keyword phrase generator reflected;

oilfield classifieds drilling classifieds oilfield services classifieds

[oilfield classifieds drilling classifieds oilfield services classifieds]

or

oilfield classifieds drilling classifieds oilfield services classifieds

"oilfield classifieds drilling classifieds oilfield services classifieds"

or

oilfield classifieds drilling classifieds oilfield services classifieds

+oilfield +classifieds +drilling +classifieds +oilfield +services +classifieds

I don't know which keyword phrase would be most effective, nor do I understand if I am to combine the two lines, utilized in a keyword phrase or just one.

[drillingtrader]

I'm creating the page for optimization.

My top four contenders are usiing the word 'classifieds' in their key word phraes.  If you do a Google search you will see what I am talking about.

I'm confused now, could you please help.

What about the appropriate way to create the keyword phrase.

Thanks, b

[EGOL]

Are you preparing this for page optimization or adwords targeting?

btw.... oilfield is two words....

...and nobody is searchin' for classifieds.... maybe you want to consider terms that target a commodity - for example:  "oil field supplies" or "drilling equipment"