Harbour and Serica: two deep-value oil stocks for your portfolio

Two oil stocks are amongthe cheapest equities on the London market today.Harbour Energy (LSE: HBR) and Serica Energy (LSE: SQZ) are trading at price-to-earnings (p/e) ratios of 5.3 and 2.7, respectively, for 2026 based on figures compiled by Peel Hunt. On a cash flow basis, the companies look even cheaper. The shares are trading at free cash flow yields of 35% and 29.9%, respectively, and a large chunk of this cash is flowing right back to investors. Harbour is trading with a forward dividend yi