Although entry 1 lists him as serving in the 91st Pennsylvania, the rest of the evidence I have reports him as serving in the 90th Pennsylvania.
He served in the 90th Pennsylvania. He was mustered in company D on 12 December 1861. [sources: 1 (91st PA), 3, 4, 5, 6, 7]
He was captured, and held in a prison in Andersonville. [source: 1]
He was seriously wounded twice. [source: 1]
On 26 November 1864, he was transferred, to company D of the 11th Pennsylvania infantry. [sources: 5, 6, 7]
When the 11th Pennsylvania mustered out, he was absent, wounded. [source: 4]
On 28 January 1865, he applied successfully for a pension (certificate 41,118). [sources: 6, 7]
On 5 April 1886, he died, in Philadelphia, Pennsylvania. On 8 April 1886, he was buried, from his residence, 1806 [?] Christian Street, Philadelphia Pennsylvania. Members of the Schuylkill Hose Company were invited to attend his funeral. [sources: 1, 2]
On 11 November 1889, his widow, Margaret, applied successfully from Pennsylvania for a pension (certificate 290,899). [sources: 6, 7]
1 'Mustered out', National Tribune 15 April 1886, page 6 (transcribed 7 February 2013, from the Library of Congress, Chronicling America)
2 death notice, Oliver Reynolds, Philadelphia Inquirer 8 April 1886, page 5; transcribed 7 Feb 2014, from GenealogyBank
3 National Park Service, Soldiers and sailors database (Oliver Reynolds)
4 Bates, Samuel Penniman. History of Pennsylvania volunteers, 1861-5. Harrisburg: B. Singerly, state printer, 1869-71. 5 volumes. 'Eleventh regiment', volume 1, pages 282. available at Making of America (accessed 8 February 2014) (Oliver Reynolds)
5 Bates. History of Pennsylvania volunteers, 1861-5, 'Ninetieth regiment', volume 3 page 168. available at Making of America (accessed 8 February 2014) (Oliver Reynolds)
6 Pension index, by unit (available at Fold3 (accessed 8 February 2014)) (Oliver Reynolds)
7 Pension index, by name (available at Ancestry (accessed 8 February 2014)) (Oliver Reynolds)
REYNOLDS.--In Philadelphia, April 5, Oliver Reynolds, aged 50, from disease contracted while a prisoner in Andersonville. He served in the 91st Pa through the war, and was twice severely wounded.
REYNOLDS--On the 5th inst., OLIVER REYNOLDS
The relatives and friends of the family, also all the organizations of which he was a member, and the surviving members of the Schuylkill Hose Company, are respectfully invited to attend the funeral, this afternoon, at 2 o'clock, from his late residence, No. 1806 [??] Christian street.