关于may / might well的用法通常有以下几种（你的问题属第2条）：

1. may well“很可能; 有充分理由可以; 完全可以”。如：

This novel may well become a classic. 这本小说很有可能会成为经典作品。

You may well participate with us in our gains. 你们完全可以跟我们共享利益。

▲ 这种结构还可以用倒装句式。如：

She can turn down your request, and well she may (do so). 她可以拒绝你的要求，并且她有充分的理由这么做。

2. may / might as well“最好; 不妨; 还不如”；注意：had better... 最好......(积极心态)；may / might as well ...“还是......好”(消极或无奈)。如：

Since he won’t listen to you, you may as well let him be. 既然他不听你的，那就随他去吧。

Now that you’ve got a chance, you might as well make full use of it. 既然你有一次机会，你还是充分利用它为好。(1999年全国高考11小题)

3. may as well ... as...“完全可以把......像......一样”；如：

You may as well call a bike as a bicycle. 你大可把bike叫做bicycle。

You may as well treat him as your own son. 你完全可以把他当作你的亲生儿子。

4. might as well ... as ...“与其......不如......”；如：

You might as well throw money into the sea as lend it to William. 你与其借钱给威廉，还不如把钱扔到海里。