Note I am not educated in legal issues. But I wil give this a try. All I write here is as far as I know and heard.
Humanity do not have rules for this that are automatic accepted for the whole world.
Trademarks can be registered or not registered. The registration can be for Europe USA or other area's. What the registration means is dependant of the registrar's rules.
If you register a domainname in which a part of the name is openerp it is yours and you can do anything with it what you want. If you miss use (e.g with a porn site) in the opinion of Open ERP SA, they can try to sue you but it depends on the law in the country they sue you.
The same as the name OpenERP, the logo can be registrered. This can be done at the same registrars. But a logo falls also often under rules for creative property so it is more protected.
In most countries it is not allowed to use a logo or other intellectual properties including text (e.g. books or small parts of it) from others.
There is another important thing. OpenERP SA has stated rules for the use of there software and documentation. I haven't studied this.
Note: Rules about what is allowed or not is not the same as how to end the mis-use. This is more complicated.
If you want to use the logo of openERP and the name sec or in a part of an other name I think it is best to ask OpenERP SA if they will accept the use you want to make of it.
Good question, a summary of licensing policy is welcome.