Comparison of user class objects is not supported in LINQ to entities

The LINQ expression is:
VaR query = from P in _ dB. logprojects
Where p. Well = Well
Select P;
(Well is a user class)

An exception will be thrown:
Unable to create a constant value of Type 'Closure type'. Only primitive types (for instance int32, string and guid) are supported in this context.

So, you can change the LINQ expression:
VaR query = from P in _ dB. logprojects
Where p. Well. wellid = well. wellid
Select P;

Reference:
ADO. NET Entity Framework comparison frustration
Entity Framework comparison frustration: explained