Well is the necessary road for human to explore and exploit underground resource. Drilling is the project focus on well construction and information measurement. Drilling engineering runs an important role in oil gas development. Drilling engineering tend to take more than 50% of the total investment. Often hundreds or even thousands of wells should be dig in the process of developing oil gas field. Different kind well has different technical requirements. (Such as product wells, water inject wells, exploratory wells, observation wells and check wells used for check water wash effect on oil.) The well drilled should not have pollution to hydrocarbon zone. A high quality well can withstand all kinds underground work for decades.。Enhance drilling technology and management and increasing drilling speed is the key to reduce cost.
The drilling has thousands of years for human being. Through history, well drilling can be boiled down to four ways historical transformations normally, (1) artificial digging well; (2) artificial percussion drilling; (3) acble drilling; (4) rotary drilling. Nowadays, the rotary drilling is a widely used method especially in the oil gas development process which has about 100 years development history.
According to historical records, the first natural gas well was dig in Sichuang Chengdu Shuangliu area as early as 250BC. Oil well is drilled in the extension of north china Yanchang, Yangchuang and other regions in A.D. 1303 years ago. Oil well is also drilled in Sichuan Leshan of china in A.D. 1521. The city Sichuan Zigong is one of the important birthplace of ancient drilling technology in china. It is the cradle of china fifth great invention (deep drilling technology). The whole city of Zigong is a large exhibition game of ancient drilling. There establish various ancient boring towers as high as 50～100m and the deepest Zi sea well (1001.42 deep well). This well consistently product brine and natural gas for more than 160 years(1835~1989) which is the word most.
The Chinese drilling technology come to the west, and the major European countries conducted a series of experiment. And the machinery drilling which used steam engine as power is invented basing on the china drilling technology. And at last the lead the rotary drilling method comes to be. And it is began to apply in petroleum engineering field since 1901. Generally machinery's drill (the United States, 1859) is thought to oil drilling start in American
European applied Chinese drilling technology in salt well in 1834. In 1841 this technology is started to apply in oil well drilling. In 1848, Russian drilled their first oil well. The United States people Draco (E H Drake) captain drilled first oil well with commercial exploitation value by machinery's drill method in Pennsylvania oil bay in 1859. This oil well depth is only 21.64m. That was widely considered as the beginning of the modern petroleum industry. The first natural gas well was drilled in 1668 later than china 1900 years almost.
In the book ancient Chinese science and technology civilization history British scholar Needham (Joseph Needham) doctor thought that: Chinese ancient drilling technology has a great enlightenment based and role to the world to the world oil gas exploration and development technology. It leads hundreds and even thousands of years in the international. He said: the drilling deep well or burrowing technology used today in oil well exploration is surely invented by Chinese; it is 1100 years earlier than the west. He also said: the Zhuotongjing process innovation went to the west in the 11th century. Until 1900 A.D., the entire world's deep well, basically are drilled by the method Chinese created
However, in the rotation drilling field, the western developed countries (Europe and the United States as a representative) have been in a leading position, and China is obviously fall behind.
Drilling technology development history at home
In time can be divided into four stages
- Ancient drilling: before 1840, Chinese ancient technology comes from cutting well salt.
- Recent drilling: 1841~1948, cable drilling technology, using power in oil well drilling date from 1907.
- Modern drilling: 1949~2000, our country drilling technology system establishment and perfect.
- 21century drilling: since 2001. Main is high temperature high pressure deep well drilling technology, super deep well drilling technology ,level drilling technology, special process drilling technology, 3 d controllable and visualization drilling technology.
Drill technology development history abroad.
In the world, the development history of rotary drilling is often divided into the following four stages.
- Concept period(1901~1920): Began to make wash well and drilling well together, and begin using roller bit and cement cementing technology
- Development period(1920~1948): roller bite, cementing process and drilling fluid obtained further progress, at the same time, high power drilling equipment appeared.
- Scientific drilling period(1948~1969): The drill string mechanics and well deflection control technology; Jet drilling; Set tooth sliding seals bearing bit; Low solid phase, solid free not scattered system drilling fluid and solid control technology of drilling fluid solid; Drilling parameters optimization; Formation pressure testing, well control technology and balance pressure drilling, etc
- Automation drilling period (1970~21 century): P DC bit; Computer application; Special process drilling technology; Comprehensive logging and underground drilling measurement; Drilling tools and equipment automation development, etc.
Drilling technology development present situation at home and abroad
(1）drilling technology development present situation
Rotary drilling technology had been invented in the twenty century already. Up to now, it is still a main important drilling method and be widely used all over the world. On the rotary drilling development course, the technology and equipment have been developed obviously since 1970s.
For nearly 50 years, oil drilling scale unceasingly expands. Drilling rig used every year increase from 8 sets in 1950s up to 700 sets in 2000s and even come to thousands of set at the most. Drilling footage every year rises from less than 5000 meters to 17 million meters. well completed every year rises from umpty up to more than ten thoudands. The drilling well area turns from land, desert region to beach area. And the drilling depth changes from shallow and middle-deep wells to deep wells. Drilling type transfers from general vertical well, cluster well, directional well to horizontal well, extended reach well and many-branched Wells etc. Especially, more than 30 years reform and open, Chinese drilling technology is quickly developing. And drilling productivity improves greatly. Every year land drilling crew average footage from 1979 meters in 1999 climbing to 25743 meters, increased by 1.88 times. Average penetration rate increases from 4.31 m/hour in 1979 up to 11.32 m/hour in 1999, increased by 1.63 times. At present, our country's drilling workload is the world's third largest, second only to America and Russia. And we has already mastered the technology such as conventional directional well, horizontal wells, old well sidetracking, cluster well and deep well. Basically can satisfy the general demand of domestic oil and gas exploration and development, and narrowed the gap with the international advanced level.
(2）The gap of drilling technology in our country contrast to the world advanced level
Research results show that the level status of our country drilling equipments and technology in the deep well, super deep well (mainly deep exploratory wells) still has gap with the world level, average well construction period and bit amount used is more than 2 times of the United States’.
The well drilling and well completion technology of horizontal well and complex structure to the stability of east old oil fields and recovery strategy improving is very important. However, compare to international advanced level, the horizontal well drilling in quality, efficiency and scale still lags far behind. Especially in the super short radius and sidetrack horizontal well drilling , the gap is bigger In the well drilling and well completion of the complex structure well (many-branched Wells, etc) and continuous soft tube drilling and sleeve drilling and so on, it is almost still in the blank in China.
Extended reach well is particularly advantageous to the exploration and development of beach and Marine oil and gas resources. At present the maximum horizontal displacement of the extended reach well drilled in our country land beach area have not yet reached to 3500 m. (overseas has breakthrough 10000 meters) The technology and equipment has big disparity also. The whole situation of drilling equipment in China is relatively backward, and automation degree is lower.
In short, China's overall drilling technology level, compared with the international advanced level is behind about 5 to 10 years.