Why did the shale gas revolution take place in the United States? Which oil and gas fields in China have similar revolutionary breakthrough prospects? What is the mission and dream of the new generation of petroleum geologists in China? At the beginning of the 21st century, these problems deserve serious consideration by Chinese petroleum geologists.

Shale gas development in the United States can be divided into accidental discovery stage (1821 ~ 1976), development exploration and technology R & D stage (1976 ~ 2005) and rapid oil and gas development stage (since 2006). By 2012, shale gas production in the United States had exceeded 230 billion cubic meters, greatly alleviating the pressure of conventional oil and gas exploration and making up for the oil and gas demand gap formed by rapid economic development. There are five main reasons why this revolution took place in the United States.

First, demand driven. In the early 1970s, the energy crisis and the decline after the peak of U.S. oil and gas production triggered concerns about the security of U.S. oil and gas energy supply. The U.S. government decided to start exploring unconventional oil and gas resources to ensure oil and gas supply. Second, there are abundant shale gas resources as the basis. In 2012, according to the statistics of the U.S. Energy Information Administration (EIA), the technically recoverable resources of shale gas in 48 states in the United States were 750 trillion cubic feet. Third, technical support. The breakthrough of core technologies such as staged fracturing in horizontal wells has paved the way for its development. Fourth, institutional guarantee. Around the shale gas revolution, the U.S. government, multinational energy giants, small and medium-sized enterprise companies and technical service companies play their respective roles, and have perfect systems and mechanisms in financing basic scientific research projects, formulating tax policies, promoting the large-scale shale gas industry, technology commercialization, resource capitalization and technical service specialization. Fifth, the role of innovative culture. In recent five years, I participated in the annual meeting of American Petroleum Geologists (AAPG) twice. From the micro earthquake reported in 2009 to the research on the relationship between lightning and oil and gas proposed in 2013, they all reflected a strong sense of innovation.

In China's oil and gas geological research, which fields also have the same revolutionary breakthrough space as American shale gas? What are the opportunities and challenges for Chinese petroleum geologists? Combined with China's actual geological background and the distribution characteristics of oil and gas resources, it can be summarized as the following five fields worthy of consideration and in-depth study by China's petroleum geologists.

One is the superimposed basin field. The basic characteristics of China's geotectonics are small stable blocks, strong activity, and the superposition of marine facies, marine continental transitional facies and continental facies, forming a unique superimposed basin in China. Oil and gas superimposed basins have experienced multi-stage tectonic activities, development of multiple sets of source rocks, multi-stage reservoir formation and multi-stage oil and gas accumulation and dispersion processes. Important scientific issues such as basin forming dynamic mechanism, lithofacies paleogeography reconstruction, coupling relationship between burial history and hydrocarbon generation history, recovery of oil and gas accumulation and dispersion process, analysis of reservoir forming system and recovery of denudation amount need to be deeply studied by petroleum geologists.

The second is the field of marine carbonate rocks. China's land facies covers an area of about 3.3 million square kilometers. The national marine oil and gas resources are 35.9 billion tons (oil equivalent), including 13.5 billion tons of crude oil and 22.4 trillion cubic meters of natural gas. The oil exploration rate is about 17% and the gas is about 10%, and the remaining resources are large. However, because marine carbonate rocks in China are mainly distributed in superimposed basins, formed early and buried deeply, the development of marine carbonate oil and gas still faces many problems, such as oil and gas source correlation and tracing, high-quality reservoir development mechanism, preservation and caprock dynamic evaluation, migration characterization and description, selection evaluation method and so on.

Third, deep oil and gas field. With the increasing difficulty of medium and shallow oil and gas exploration, deep oil and gas exploration has attracted great attention of petroleum geologists all over the world. The theme of 2013 AAPG annual meeting is "go deep", which is enough to show the importance of deep oil and gas field. Recently, academician Qiu Zhongjian pointed out at the deep and unconventional International Seminar: "deep oil and gas will make important contributions to mankind like shale gas." According to relevant asset evaluation results, China's deep oil resources are 30.4 billion tons, natural gas is 26.88 trillion cubic meters, the proved reserves are only 1.793 billion tons and 1.64 trillion cubic meters, and the remaining resources are extremely rich. However, due to the deep burial of deep oil and gas, petroleum geological problems such as hydrocarbon phase behavior and reservoir forming dynamic mechanism still need to be studied.

Fourth, shale gas and shale oil. There have been many studies related to shale gas, which will not be repeated here. However, lacustrine shale rich in organic matter is widely distributed in China, with relatively young geological age, high total organic carbon content, large thickness, shallow burial and low thermal maturity, showing good shale oil resource potential. However, there are still problems in the field of shale oil, such as occurrence mechanism and resource evaluation, shale oil flow mechanism and optimization design