In 1895, Marcus Samuel received a concession in the Kutei area of east Borneo, and based on oil seepages in the Mahakam River delta, Mark Abrahams struck oil in February 1897. This was the discovery of the Sanga Sanga Oil Field, a refinery was built in Balikpapan, and discovery of the Samboja Oil Field followed in 1909. In 1901, the Pamusian Oil Field was discovered on Tarakan, and the Bunyu Oil Field in 1929. Royal Dutch Shell discovered the Miri Oil Field in 1910, and the Seria Oil Field in 1929.