Fine Exploration of Nanpu Oilfield in Jidong

The discovery of Nanpu Oilfield is the result of adhering to the theory of oil-rich sag in eastern continental basin and strengthening the fine exploration of structural oil and gas reservoirs. This is what they call "one theory and four techniques".

Specifically, the so-called "one theory" refers to the theory of fine exploration of oil-rich depressions in eastern continental basins, that is, fine exploration of oil-rich depressions with resources of more than 200,000 tons/square kilometer. "Four technologies" refer to three-dimensional seismic exploration accurate description technology, rapid drilling and reservoir protection technology, directional drilling technology and wellbore reservoir and oil and gas reservoir evaluation technology.

In Jidong Oilfield, the implementation of fine exploration is reflected in all aspects of the work. However, everyone is emphasizing one point: second, three-dimensional seismic exploration is a key point.

What is 3D seismic exploration? It's underground information fed back by artificial seismic waves. Experts say that doing three-dimensional seismic exploration is equivalent to doing CT for the earth. Oil prospectors describe seismic exploration as follows: If drilling is compared to a pair of hands of geological discovery, then seismic exploration is a pair of eyes of geological discovery. In eastern Hebei, improving the quality of seismic exploration is regarded by decision makers as the key point to break through the bottleneck of exploration.

The second 3D seismic exploration was actually only three years after the completion of the first 3D seismic exploration. Three-dimensional seismic exploration technology is costly and difficult. Can the second 3D seismic exploration solve the problem? The result is unpredictable, and everyone's mood is very heavy.

From 65438 to 0997, Jidong Oilfield decided to conduct the second 3D seismic exploration in the main body of Laoyemiao structural belt in the old exploration area, and the result was an instant hit. The seismic exploration map taken out is much clearer than the first image. This key experiment makes people's geological understanding of Laoyemiao structural belt gradually clear. According to the evaluation, the success rate of a batch of exploration wells deployed on this basis reached 82%, and the newly proven petroleum geological reserves were13.6 million tons.

This success is a milestone in the history of oil and gas exploration in eastern Hebei. Because it shows that the second 3D seismic exploration is not only necessary, but also very effective. Since then, they have conducted the second 3D seismic exploration in Gaoshangbao, Liuzan and other areas, and also received unexpected surprises.

The biggest function of the second 3D seismic exploration is to improve people's understanding of underground geological conditions. Various underground geological targets have become a huge database through three-dimensional seismic exploration technology, which enables geologists to fully understand the underground geological situation from different angles on the computer, and the understanding degree is greatly improved.

Three-dimensional seismic exploration not only brings accurate information description, but also has direct guiding significance for oil exploration in this area.

After the second 3D seismic exploration in Liubei area, great changes have taken place compared with the original understanding. In the original drawing, according to the working idea of complex fault block oilfield, many reservoir changes are mistaken for faults. However, after the second 3D seismic exploration data came out, through re-understanding the reservoir characteristics, it was found that the original single well formation loss was caused by reservoir changes, and the original thought fault block reservoir became a fault nose reservoir. The oil and gas reserves in this area have jumped from 4 million tons to more than 30 million tons.

The second 3D seismic exploration is like a golden key to the underground maze. Since then, the exploration situation in Jidong Oilfield has turned for the better.

However, can the exploration experience on land also be applied to the sea?

The exploration of Nanbaotan in Jidong Oilfield began in 1980s, during which it went through the stages of self-management and medium-term foreign cooperation. As a risk exploration partner of PetroChina, an American company drilled two wells in the coastal area of eastern Hebei, costing tens of millions of dollars, but found nothing. Since then, an Italian company has also drilled in this area and found no industrial oil flow.

In 2002, Jidong Oilfield recovered the exploration right from foreign companies. According to the geological knowledge, exploration experience and technical preparation obtained on land, a large-area, one-time high-precision three-dimensional seismic exploration was carried out in Nanbaotan sea area. Later, it turned out that this laid a solid foundation for Nanpu Oilfield to find large oil fields so quickly.

During the SARS period in 2003, Zhou Haimin, general manager of Jidong Oilfield, organized more than 20 geologists to carry out the secondary development of geological data. Four months later, an amazing discovery was made: a large number of missing oil layers were found in the shallow layers of more than 300 wells, with considerable reserves. Three exploration wells were quickly drilled, and as expected, after re-understanding the old exploration area of Gaoshangbao, hundreds of millions of tons of reserves were discovered in the middle and shallow layers.

May 23, 2004, Jidongtan sea area. After careful preparation, the first exploration well-Laobao South 1 was laid by oil prospectors in eastern Hebei where foreigners failed to drill wells. Only four months later, at 4 o'clock in the afternoon on September 29th of that year, Zhou Haimin received a call from the site supervisor of Laobao South 1 Well: "Ignition, 700 cubic meters of crude oil per day!"

Many people can't believe the news. Until the oil sample is taken, it is impossible for people engaged in oil to know about crude oil, but the excited people still put the oil in the washbasin and ignite it, and then verify it.

In the same place, why didn't foreign companies return, but it worked in one fell swoop to find oil people in Jidong? Zhou Haimin told us: First, the foreign side did not know enough about the rich reservoirs in Nanpu area, and the result did not persist; Second, there was an error in the direction of selection, and there was oil in the middle and shallow parts, but they drilled deep and didn't get out; Third, the degree of work is not enough. Foreign companies want to take a short break and find integrated oil fields and high-yield oil fields as soon as possible. I didn't expect the situation in this area to be so complicated, and finally they passed by a big oil field.

After the discovery of Laobaonan 1 well, the drilling work started in an all-round way. In April 2007, the first 1,000-ton well-NP1-P4 was born in Jidong Oilfield.

Using advanced technology to build and develop oil fields

Nanpu Oilfield, a new type of oilfield, is under construction.

On May 12, we saw an oil pipeline with a diameter of about 60 cm lying on the side of the road at the drilling site of Nanbao Oilfield, and its bright bright yellow was very eye-catching. This pipeline connects Nanbao and Qian 'an, passes through Gaoshangbao, and stretches for more than 120 kilometers. The car goes along the pipeline and reaches the artificial island 1 in Nanpu Oilfield.

Centralized development by using artificial islands is an important measure to build a scientific and technological oilfield in Nanpu Oilfield in eastern Hebei Province. According to reports, compared with offshore steel platforms, artificial islands have the advantages of low cost and long life. The island is 704 meters long, 4 16 meters wide and 8.2 meters high. The outer ring road is 2020 meters in circumference, covering an area of 4 13 mu, with a cost of 320 million yuan. Before the island was built, it was a beach area with a water depth of 2 ~ 3 meters. 4 13 mu of artificial island, plus 1.8 km of access road, which is formed by sand blowing and reclamation in half a year.

At the entrance of the artificial island, there stands a huge chart with the graphic design of the artificial island 1. In the middle of the island, there are oil and gas water treatment area, material area, drilling equipment area and power control area, and 12 drilling wellhead slot, escape tower and vent are arranged around it. At present, no oil field development well has been drilled in the 1 artificial island, and all the work is in the early stage of development. It is reported that the island will be officially put into use at the end of 2009.

According to the plan, in the near future, there will be five artificial islands standing on the beach in Nanpu area, truly realizing "centralized development". Such an artificial island not only saves the land in the sea area, but also improves the mining efficiency. According to the traditional drilling technology, drilling a well covers an area of 12 mu, and now a row of drilling 15 wells only covers an area of 13.48 mu; 1 artificial island can drill 392 wells, which alone saves more than 4000 mu of land. It used to take six days to move a drilling rig, but now the drilling rig can move the derrick by sliding on the guide rail groove, and it only takes 13 minutes to move once.

This efficient land use and efficient operation is achieved through advanced technology. Among them, horizontal well technology and wellhead grooving technology are the two most representative ones.

Generally, oil wells pass through the oil layer vertically or obliquely, and the interval passing through the oil layer is relatively short. The horizontal well is drilled vertically or obliquely to the oil layer, and the wellbore extends horizontally and remains parallel to the oil layer. The interval drilled into the oil layer can reach hundreds of meters to more than 2000 meters. Using horizontal well technology, the flow resistance of fluid flowing into the well in oil layer is reduced, and the oil production range and productivity can reach more than three times that of traditional vertical wells.

Many domestic oilfields have adopted horizontal well technology in exploration and development, but Nanpu Oilfield is the first oilfield in China that completely adopts horizontal well technology. In view of the complex geological conditions in Nanpu sag, in order to avoid reservoir pollution caused by exploration and development, Nanpu Oilfield introduced advanced geological steering well drilling technology while adopting horizontal well technology, which greatly improved the drilling success rate.

Nanbao Oilfield 1 Artificial Island only covers an area of more than 400 mu. To achieve the annual production capacity of 2 million tons, only 800 horizontal wells need to be drilled. If the traditional vertical well technology is adopted to achieve the same productivity, 2,400 wells need to be drilled, covering an area of 1.92 million mu.

In the process of artificial island development, horizontal wells save land by improving oil production efficiency and then reducing drilling times, while the application of another key technology-wellhead slot batch drilling technology actually saves a lot of land and space. Hu Wenrui, vice president of China Oil and Gas Co., Ltd., made an image metaphor. He said that the horizontal well and wellhead slot technology have turned the drilling network in Nanbao Oilfield into a "submarine centipede". The horizontal well extending in all directions is a centipede foot and the wellhead slot is a centipede body.

In the distance, the tall drilling rig serving wellhead slot technology looks nothing special. When you approach, you can find a "car" at the bottom of the rig. The "truck" has to bear the weight of 700-800 tons, and the drilling rig on it can move back and forth along the guide rail laid in the wellhead groove.

After completing the construction of a well, the drilling rig does not need to be disassembled, moved and installed as before, but moved to the position of the next well along the guide rail to continue the construction. It takes 6 days to move the drilling rig from one well location to another with traditional technology, while it only takes 13 minutes to complete the same workload with wellhead slot technology.

This technology saves a lot of manpower, material resources, financial resources and rig dismantling time, facilitates batch drilling and centralized wellhead control, and is suitable for the centralized development mode of offshore oil and land production in Jidong Oilfield.