Fig. 3.33 Division of reserve growth stages in 48 states of the United States (excluding deepwater areas).
3.3.2. 1 initial stage (1900 ~ 19 19)
At the beginning of the 20th century, the United States began to enter the "gasoline age" from the "kerosene age", and the rise of internal combustion engines promoted the increasing demand for petroleum products, especially after World War I (1914 ~1918). All these have prompted oil companies to start looking for more crude oil and promoted the exploration work.
During the period of 1900 ~ 19 19, the recoverable reserves of 48 states in the United States (excluding deepwater areas) increased by an average of 56 million tons per year. The recoverable reserves of new crude oil increased by 4.7 1% annually, but the absolute increase was not large, from 63 million tons in 1900 to 654.38+20 million tons in 19 19.
From the indicator of proven resource rate, the annual proven resource rate has increased from 0. 19% to 0.36%, and the annual proven resource rate is 0. 17%. Up to 19 19, the cumulative proven rate of resources in 48 local states (excluding deep water areas) is 4.42%.
Judging from the exploration workload, this stage is the initial stage of American petroleum industry, and the density of exploration wells is not large. By 19 19, the density of exploration wells is about 3.34 wells/10,000 square kilometers. At this stage, a series of large oil fields were discovered in 48 States of the United States, mainly in California, Ohio and Oklahoma. According to the statistical results of EIA, in 2004, 65,438+00 oilfields with the largest remaining crude oil reserves were discovered in 48 states (excluding deepwater areas) [28].
Theoretically and technically, this stage was dominated by ground geological work, and anticline theory was the main geological theory at that time. With the accumulation of practical exploration experience, petroleum geology has become a branch of geology.
Judging from the national energy policy of the United States, the government recognizes the importance of oil resources and implements the policy of "deduction of hidden drilling development cost" to promote exploration reinvestment.
3.3.2.2's rapid growth stage (1920 ~ 1945)
During the period of 1920 ~ 1945, the average annual recoverable reserves of crude oil in 48 states in the United States (excluding deep water areas) increased by 2130,000 tons. The newly-increased recoverable reserves increased from 1.920 to/.29 million tons to 1.945 to 285 million tons, and the growth rate of newly-increased recoverable reserves reached 4.84%. From 1929 to 1935, a serious economic crisis occurred in the United States, which was the most serious during the period of 193 1 ~ 1933, and the oil price was even lower than 1. Under the condition that Oklahoma City Oilfield and East Texas Oilfield are discovered continuously in 1928 ~ 1930, the newly-increased recoverable reserves in 1932 are only 0.1200 million tons, which indicates that the exploration activities have decreased sharply due to the influence of economic and market environment. If the data of newly-increased recoverable reserves in 193 1 ~ 1933 are not included, the newly-increased recoverable reserves in this stage will reach 235 million tons.
At this stage, the annual proven rate of resources jumped from 0.39% to 0.85%, among which 1929, 1937 and 1938 all exceeded 1.20%. The annual average proven rate of resources at this stage is 0.64%. If the data of 193 1 ~ 1933, which is most affected by the economic crisis, are excluded, the annual average proven rate of resources at this stage is 0.7 1%. By 1945, the cumulative proven rate of crude oil resources in 48 local states (excluding deep water areas) reached 2 1.40%. The rapid growth of new recoverable reserves at this stage benefits from the rapid growth of exploration workload. The density of exploration wells in 48 local states has increased from 3.79 wells/10,000 square kilometers in 1920 to 70 wells/10,000 square kilometers in 1945.
From the perspective of exploration theory and technology, since the 1930s, the concept of modern petroleum geology has basically taken shape, the theory of trap oil exploration has become the main theory, and the basic concepts of oil generation, migration and accumulation have been clarified. Geophysical method is the main exploration method at present. 1923, experimental new scale and refraction seismographs began to appear in the United States, and they were successfully applied in the Gulf of Mexico. Since 1925, these exploration methods have been rapidly popularized in American oil exploration. After 1930s, seismic reflection method was successfully applied in Oklahoma, Gulf of Mexico, Texas and California. Since the 1940s, the seismic technology has been continuously improved, and the exploration ability in complex areas and deep layers has been improved.
At this stage, the number of newly discovered oil fields in 48 local States (excluding deepwater areas) has also increased significantly. During the 26 years in this stage, 27 large oil fields with remaining proven reserves were discovered in 48 states (excluding deep water areas), and they were still in front of the United States in 2004 100.
In order to promote the development of petroleum industry, the United States government began to implement the policy of "consumption percentage allowance" from 1924. This preferential measure has maintained a large number of exploration risk funds for the US oil industry. 1935 "Connaught Petroleum Act" effectively prevented oil-producing states from selling oil exceeding the quota at low prices, stopped the chaotic situation of oilfield development, protected the oilfield and stabilized the domestic oil price in the United States.
3.3.2.3's stable growth stage (1946 ~ 1970)
After World War II 1946 ~ 1970, the rapid economic growth in the United States continued to drive the development of the petroleum industry, and the newly-increased recoverable reserves in 48 local states (excluding deep water areas) maintained a high and stable growth trend during these 25 years. 1946 increased recoverable reserves by 363 million tons, 1970 increased recoverable reserves by 41900 million tons, of which the newly increased recoverable reserves reached the peak in 195 1 year, reaching 602 million tons. At this stage, the recoverable reserves increase by 388 million tons annually, and the average annual growth rate of new recoverable reserves is 0.64%.
Judging from the proven rate of resources, the proven rate of resources in this stage is mostly above 1%, with an average annual proven rate of 1. 16%. It is precisely because of the high and steady growth of newly-increased recoverable reserves that the proven rate of accumulated resources has also greatly increased during this period, from 22. 1% in 1946 to 50.79% in 1970. At this stage, the exploration workload increased rapidly, and the density of exploration wells increased from 79 wells/10,000 square kilometers in 1946 to 456 wells/10,000 square kilometers in 1970. The rapid growth of exploration well density is an important basis for the steady growth of newly-increased recoverable reserves. During this period, the remaining proven reserves of the newly discovered 16 oilfields are still before the United States in 2004 100.
At this stage, the development of oil and gas exploration theory and technology has made great progress. Theoretically, trough platform theory, biostratigraphy and marine oil generation theory were put forward in 1950s. Revolutionary plate tectonics and chronostratigraphy were born in the 1960s. Technically speaking, the digitalization of seismic technology in the early 1960s increased the density of underground coverage and improved the accuracy of seismic exploration. All these provide a solid theoretical and technical foundation for the stability of newly-increased recoverable reserves at a high level.
Judging from the national energy policy, the United States continues to implement a proactive oil policy at this stage, and the domestic oil price in the United States is always higher than the international oil price at this stage. The high oil price policy protected the domestic oil industry from the international oil price downturn at that time and promoted the rapid development of oil exploration in the United States.
3.3.2.4 decline stage (197 1 ~ 2004)
197 1 During the period from 2004 to 2004, the recoverable reserves of crude oil in 48 states in the United States (excluding deepwater areas) increased by 2130,000 tons annually. The newly-increased recoverable reserves showed a downward trend, from 3 197 1 year to 0/60,000 tons in 2004. The annual decline rate of new recoverable reserves in this stage is 1.6%.
Judging from the proven rate of resources, the annual proven rate of resources at this stage is 0.64%. It is precisely because the newly-increased recoverable reserves began to decline that the cumulative proven rate of resources began to slow down during this period, with 197 1 year being 5 1.80% and 75.63% in 2004.
At present, the exploration workload is still relatively large, and the density of exploration well pattern has increased from 466 wells/10,000 square kilometers per year in197/kloc-0 to 796 wells/10,000 square kilometers in 2004. Due to the maturity of exploration in 48 States (excluding deep water areas) in the United States, although the exploration workload has increased greatly, the number of newly discovered large oil fields has decreased significantly compared with the previous three stages. During this period, by 2004, only two newly discovered oil fields in the United States had the remaining proven reserves of the first 65,438+000.
At this stage, the theory and technology of oil and gas exploration have been further developed. Theoretically speaking, since 1970s, the global tectonic theory with plate tectonics as the core has developed rapidly, which has deepened the understanding of the close relationship between oil and gas and sedimentary basins, and can dynamically evaluate the oil and gas prospects of sedimentary basins as a whole through the classification of basins. After 1990s, the general trend of theoretical research on oil and gas geology is to develop in the direction of refinement, quantification, multidisciplinary integration and mutual penetration. The theory of petroleum system is further improved, and high-resolution sequence stratigraphy and holographic stratigraphy are developed. Technically speaking, since 1970s, the development and application of multi-channel seismic acquisition system, various longitudinal-wave vibroseis and the improvement of other non-explosive sources have greatly improved the seismic exploration capability. The application of 3D seismic technology improves the success rate of exploration. Since 1990s, enhancing oil recovery has become an important field of geophysical activities in the United States. High-resolution seismic and cross-well tomography technology has become the focus of research and development.
Since 197 1, the United States has experienced two oil crises. In order to protect the American economy, during the two oil crises, the government adopted the policy that the domestic oil price was lower than the international oil price. Since the 1980s, some exploited oil fields in the United States have gradually entered a recession stage, and the American government has taken some preferential measures to stimulate the development of the oil industry, such as canceling the oil price control, exempting low-yield oil and gas operators and royalty owners from the crude oil windfall tax, and encouraging the exploration and development of new oil fields and unconventional crude oil.
With the decrease of new recoverable reserves of crude oil, the US government began to pay attention to the development of unconventional oil and gas resources and deepwater oil and gas resources, and formulated corresponding tax credit policies. Since the mid-1980s, deepwater oil and gas resources have become the focus of oil and gas exploration and development in the United States. Especially after the promulgation of 1995 "deep water mining royalty exemption law" (DWRRA), the newly-increased recoverable reserves in deep water are huge. According to the report of us energy information administration in 2004, during the period of 197 1 ~ 2004, the United States discovered 28 large oil fields with remaining proven reserves, of which 26 were located on the outer continental shelf.