It is well known that the series $\sum_{p\in \mathbb{P}} \frac{1}{p}$ diverges where $\mathbb{P}$ denotes the set of primes.  Brun proved that $\sum_{p\in \mathbb{P_2}} \frac{1}{p}$ converges where $ \mathbb{P_2}$ denotes the set of twin primes.  Now for an even integer $k$ let $\mathbb{P}_k = \{ p, q \in \mathbb{P}: |p-q| \leq k\}$.  By Zhang's result we know that $\mathbb{P}_k$ is infinite for $k$ larger than some threshold $N$.  My question is what is the smallest value of $k$ for which $\sum_{p\in \mathbb{P}_k} \frac{1}{p} = \infty$?  Or does no such finite value exist?  Moreover, what are the asymptotics for these sums as $k \to \infty$?

<b>Edit (S.K.):</b> Since the question has more or less been answered in the comments and has already 2 close votes, let me try to turn this into a more on-topic question:
does the series still converge if we take the sum over all reciprocals of primes $p$ whose distance to the next prime is less than $\frac{\log p}{\log \log p}$?