An annulment is not a Church divorce. Annulment and divorce are two entirely different entities. Each has a different process, different grounds, and a different focus; consequently, each one has different effects.
A civil divorce declares that a marriage did occur but, for some reason the marriage is no longer a civil entity. Often there is a blame attributed, such as adultery, mental cruelty, abandonment, and so forth. Simple incompatibility between husband and wife after thirty years of marriage would also qualify as a ground for divorce. The focus of a civil divorce is either what had occurred during the marriage, or that the parties simply no longer wish to be married. As a result of the civil divorce process, the parties who had once been married are now declared by the State as no longer married.
A church annulment also declares that a marriage did occur, but for a particular and proven reason, was not binding. There is no blame attributed to either party since the grounds established would be solely to determine the basis upon which the marriage lacked validity at the time it was contracted. Canonical grounds for an annulment are entirely different from civil grounds for a divorce.
The focus of the annulment process is not the marriage but the actual contractants of the marriage and the relationship of each to the other at the time they gave their consent to marry.
A civil divorce concerns the circumstances of a marriage. A Church annulment concerns the circumstances of the relationship of the parties who had given their consent to enter that marriage. Only when a clear and accurate picture of the courtship and early years of the marriage has been established could there be a possibility of establishing grounds upon which the case can proceed to a definitive conclusion.