Although there are numerous studies on collocation in English writing by L2 university students, little is known about the problems encountered by mature researchers writing authentic L2 English texts in their fields. This study investigates collocation issues in L2 English research papers in Brazil. Its starting point was the compilation of the Brazilian Academic Corpus of English (BrACE), a 906,035-word multidisciplinary corpus of journal articles written in English that have been published in Brazilian journals. The most frequent noun collocations in this corpus were contrasted with the expert writing lexical database underlying the ColloCaid academic writing assistant. No evidence of systematic miscollocation was found in the published papers represented in BrACE. However, many general academic English collocations were conspicuous by their absence from BrACE, including collocations with L1 Portuguese cognates. We also observed that the collocations in BrACE were less diverse and tended to score higher in terms of strength of association than their equivalents in the reference data. In addition to feedback on miscollocations which might arise in unedited manuscripts, our findings to conclude that Brazilian (and other English L2) research writers can benefit from suggestions to expand their collocation repertoire, enhance their perceptions of collocation strength, and offset collocation avoidance.