Blockchain technology has been developed for more than ten years and has become a trend in various industries. As the oil and gas industry is gradually shifting toward intelligence and digitalization, many large oil and gas companies have been working on blockchain technology in the past two years because it can significantly improve the management level, efficiency and data security of the oil and gas industry. This paper aims to let more people in the oil and gas industry understand the blockchain and lead more thinking about how to apply the blockchain technology. To the best of author’s knowledge, this is one of the earliest papers on the review of the blockchain system in the oil and gas industry. This paper first presents the relevant theories and core technologies of blockchain, and then describes how the blockchain is applied to the oil and gas industry from four aspects: trading, management and decision making, supervision and cyber security. Finally, the application status, the understanding level of the blockchain in the oil and gas industry, opportunities, challenges, risks and development trends are analyzed. The main conclusions are as follows: (1) At present, Europe and Asia have the fastest pace of developing the application of blockchain in oil and gas industry, but there are still few oil and gas blockchain projects in operation or testing worldwide. (2) Nowadays, the understanding of blockchain in the oil and gas industry is not sufficiently enough, the application is still in the experimental stage, and the investment is not enough. (3) Blockchain can bring many opportunities to the oil and gas industry, such as reducing transaction costs and improving transparency and efficiency. However, since it is still in the early stage of the application, there are still many challenges, primarily technological, regulatory and system transformation. (4) The development of blockchains in the oil and gas industry will move towards hybrid blockchain architecture, multi-technology combination, cross-chain, hybrid consensus mechanisms, and more interdisciplinary professionals.