He joined the Society of Jesus, became a missionary, and as such began about 1701 to travel through the territories of Quillota, Polpaico, Tiltil, Limache, and others.
From 1712 until 1720 he directed the missions of Nahuelhuapi and Calbuco, and in 1730 he was in Concepción during the earthquake of July, which destroyed that city.
His frequent voyages gave him an opportunity to study the archives of the Company of Jesus, and about 1736, in Santiago, he began to compile his history.
He intended to write a complete history of Chile, when a decree of Charles III exiled the Jesuits, and, notwithstanding his advanced age, Olivares had to leave the country.
A complete edition of the work and a "Historia de la Compañía de Jesus en Chile 1593–1736," with notes by the Chilean historian Diego Barros Arana, appeared in Santiago in 1870.