Sirikit Oil Field It is an oil source located in Amphoe Lan Krabu under the Thai Shell Exploration & Production Company, the concessionaire. The company started its drill for oil and natural gas for commercial purposes in 1982. The raw oil from this source is called "Namman Phet" (Diamond Oil). The wording "Chot Chuang Chat Chawan" (splendid) has its origin from this oil sources it represents the first hope of Thailand's energy source.