Introduction to oil exploitation and exploitation technology

intro

Oil is a fluid mineral buried deep in the ground. At first, the oily liquid mineral produced in nature was called petroleum, the combustible gas was called natural gas, and the solid combustible oil mineral was called asphalt. With the in-depth study of these minerals, it is realized that they are hydrocarbon compounds in composition and are related to each other in genesis, so they are collectively called petroleum. In September 1983, the 11th World Petroleum Congress proposed that petroleum is a complex mixture consisting of gaseous, liquid and solid hydrocarbons that exist in nature, as well as a small amount of impurities. So oil extraction also includes gas extraction.

The role of oil in the national economy oil is an important energy, compared with coal, has the advantages of high energy density (the combustion heat of equal weight oil is 50% higher than that of standard coal), convenient transportation and storage, and less pollution to the atmosphere after combustion. Fuel oil derived from petroleum is the main fuel for various kilns in transport vehicles, power station boilers, the metallurgical industry and the building materials industry. Liquefied gas (LPG) and pipeline gas (PIped gas) with petroleum as raw materials are high quality fuels used in urban life. Aircraft, tanks, ships, rockets and other spacecraft also consume large amounts of petroleum fuel. Therefore, many countries have listed oil as a strategic material.

Since the 1970s, oil has surpassed coal in the composition of world energy consumption. In 1979, it accounted for 45 percent, and this situation is not expected to change much by the early 21st century. Petroleum products are also widely used as lubricants for various machinery. Asphalt is an important material for roads and buildings. Petrochemical products are widely used in agriculture, light industry, textile industry, medicine and health and other sectors, such as synthetic fiber, plastic, synthetic rubber products, has become a necessity for people's life.

In 1982, world oil production was 2,644 million tons and natural gas 1,582.9 billion cubic meters. Since 1973, three oil price increases and the 1982 oil price collapse have caused great fluctuations in the world economy (see World Oil Industry).

Oil and gas accumulation and driving mode After forming in the crust, oil and gas exist in the source gas in a dispersed state, and after migrating into the reservoir, it accumulates in the geological trap with good preservation conditions to form oil and gas reservoirs. There can be several oil and gas reservoirs in a geological structure, combined into oil and gas fields.

A rock formation with reservoir space that holds oil and gas and allows the flow of oil through it. The space in the reservoir contains the pores between the rock fragments, the cracks in the rock cracks, and the holes formed by dissolution. The pores are generally related to sedimentation, the cracks are mostly related to tectonic deformation, and the holes are often related to paleokarst. The size, distribution and connectivity of voids affect the flow of oil and gas and determine the characteristics of oil and gas exploitation (see petroleum Development Geology).

In the process of oil production, oil and gas flow from the reservoir to the bottom of the well, and then rise from the bottom of the well to the wellhead. There are mainly: (1) hydrostatic head formed by surface water recharge in water drive reservoir; (2) elastic water drive, the elastic expansion of surrounding closed water and reservoir rocks; (3) Dissolved gas drive, the expansion of the gas dissolved in the oil when the pressure is reduced; (4) Gas cap drive, when there is a gas cap, the expansion of gas cap gas with the reduction of pressure; ⑤ Gravity drive, gravity oil discharge. When the above natural energy is sufficient, oil and gas can be ejected from the wellhead. When the energy is insufficient, artificial lifting measures are needed to drive the oil flow out of the ground (see spontaneous injection oil production method, artificial lift oil production method).

Compared with the general solid mineral deposits, the characteristics of oil exploitation have three significant characteristics: (1) The object of exploitation continues to flow throughout the process of exploitation, the reservoir situation is constantly changing, all measures must be carried out in response to this situation, therefore, the entire process of oil and gas field exploitation is a process of continuous understanding and continuous improvement; ② The miner does not have direct contact with the ore body under normal circumstances. The exploitation of oil and gas, the understanding of the situation in the oil and gas reservoir and the various measures to exert influence on the oil and gas reservoir must be carried out by special logging. Some characteristics of a reservoir must be recognized during production, or even after a large number of Wells have been drilled, so exploration and production phases are often intertwined over a period of time (see field development planning and design).