How were oil and gas fields discovered?

Exploration is further divided into three sub-phases: large-scale area exploration, small-scale drilling, and evaluation and characterization of prospective areas. This stage mainly requires geologists and geophysicists, as well as drilling specialists.

The objective of the area exploration is to identify a block with exploration potential. First, the exploration data of such basins are obtained through geophysical gravity, magnetism, electricity, seismic and other means (mainly **), the regional geological history is reconstructed through the processing and interpretation of the data, and the types of basins that can accumulate oil and gas are selected according to experience, such as faulted basins or passive continental margins, and then a block with exploration potential is determined. Then it is time to rush to ask for the tenements for further exploration.

The objective of the area exploration is to identify a block with exploration potential. First, the exploration data of such basins are obtained through geophysical gravity, magnetism, electricity, seismic and other means (mainly **), the regional geological history is reconstructed through the processing and interpretation of the data, and the types of basins that can accumulate oil and gas are selected according to experience, such as faulted basins or passive continental margins, and then a block with exploration potential is determined. Then it is time to rush to ask for the tenements for further exploration.

Once the exploration blocks have been identified, more precise data is needed, including satellite aerial surveys, ** data, geological outcrops, and laboratory analysis data, through which the oil system and accumulation assemblage can be determined. After all, we have to drill to know if there is oil or not, and in order to determine the accuracy of the previous analysis, we need to drill several exploration wells. The cost of drilling a well is very high, and the cost is millions, so the choice of drilling location becomes extremely important.

The underground situation can not be seen or touched, we can only get the reflection interface of the formation through the means of the first level, get the structural map of the formation, and then determine the effective trap, so as to determine the possible drilling location. <>

Take, for example, the Shengli oil field. The Jiyang depression where the Shengli Oilfield is located (thank you friends for the correction) (part of the Bohai Bay Basin) is a typical fault basin, and there are many normal faults that make people collapse, which is very different from the Songliao Basin where the Daqing Oilfield is located. If there is no such dome-like trap that closes on all sides, then the next best thing to do is to find a faulted oil and gas field with a fault on one side and an inclined strata on the other.

Fault-block oil and gas fields are generally not large, and there are individual exceptions, such as Shengtuo Oilfield in Shengli Oilfield, which is such a relatively large integrated fault-block oil and gas field. At this time, the closure of the fault is decisive for the presence or absence of oil and gas. The determination of the fault block almost completely depends on the quality of the data.

At this point, there should be at least a few large 2D profiles for exploration. Other environments are different. For example, a large part of deep-sea exploration in the Gulf of Mexico is in sub-salt reservoirs.

The cost of deep-sea exploration is very high, and you can't drill wells as casually as on land, so you have to be very careful about the location of wells. At this time, the 3D data is not much for the budget of the whole project, so it is generally necessary to obtain very good 3D imaging data first. Sub-salt is very challenging for geophysical imaging.

In recent years, technologies such as reverse time offset have been developed to greatly improve pre-salt imaging. <>

The process by which oil and gas fields were discovered is as follows:

If a basin has not been explored at all, then first plane to measure the gravity magnetoelectric to see the general structure, and then start to select a few sites to start drilling exploration wells. Taking the Songliao Basin as an example, it is a typical concave mid-uplift, which is the simplest and easiest. Then there is no negotiation, and the well is drilled directly at a high point.

When drilling exploratory wells, the most complete data is obtained, such as logging, logging, coring, ground temperature, pressure knowledge and training, etc.

If you see oil and gas, then measure the height of the oil and gas column, continue to drill wells around until you find a more reliable trap area, and then the volume v=h*s* shape parameter planing water, and then convert the pressure and temperature into the volume of the surface, and the reserves are calculated. This is the easiest situation, and this is how a number of giant oil fields in the world have been found. This is almost no longer the case.

Oil & Gas Fields:

Oil and gas field refers to the sum of oil reservoirs, gas reservoirs and oil and gas reservoirs in the same area controlled by a single local structural unit. If there is only an oil reservoir within this local tectonic range, it is called an oil field; There are only gas reservoirs, called gas fields.

In the strict meaning of petroleum geology, it refers to the relatively independent and contiguous industrial oil and gas storage area or the geological body where oil and gas are concentrated from the ground. According to the difference of oil, gas and condensate, it is divided into oil field, oil and gas field, gas field and condensate (oil) gas field. In terms of exploration, it refers to the trap of liquid transportation with proven reserves; If there is only oil and gas discovery or only controlled and ** reserves, it is generally called an oil and gas structure (trap).

Oil fields are found in sedimentary rock distribution areas. The sum of oil and gas reservoirs in the same oil and gas production area under the control of a single geological structure (or stratigraphic) factor. An oil and gas field may have one or more oil and gas reservoirs.

In the same area, it is called an oil field, and it is called a gas field, which is mainly a gas reservoir.

Ghawar Oilfield: Located in the east of Saudi Arabia and about 500km east of the capital Riyadh, the proven reserves are up to 100 million tons, with an annual output of up to 100 million tons, accounting for 30% of the entire Persian Gulf region, and is the world's largest oilfield. The oil well is a self-blowing well, with less wax content, mostly light oil, and a freezing point of less than -20, which is easy to transport.

There is an oil pipeline through the Rastanula oil port (the world's largest oil port) for export.

Dabulgan Oilfield: Located in the southeast of Kuwait, it has proven reserves of 100 million tons and an annual output of about 70 million tons. **Similar in characteristics to the Ghawar oil field, it is mostly transported from Mina Ahmadi oil port.

Oil field. Oilfield refers to the sum of oil and gas reservoirs in the same oil and gas production area under the control of a single geological structure (or formation) factor. Oilfields are divided into three categories, namely structural oil and gas fields, stratigraphic oil and gas fields, and composite oil and gas fields.

Generally, the recoverable reserves of more than 500 million tons are extra-large oilfields, 70 million to 100 million tons or more are large oilfields, and below 70 million tons are small and medium-sized oilfields. To calculate the possible wells and the annual production, some oilfields have large reserves, but the production is not necessarily high, which is mainly affected by the driving capacity of the oilfield. Only those that have been carefully calculated from reserves to production and have economic value for mining can be formally exploited.

The sedimentary rocks found in the distribution area of the oil fields.

Sedimentary rock. Sedimentary rocks, also known as aqueous rocks, are rocks formed by the consolidation of loose sediments deposited in layers, and they are one of the three main rocks that make up the Earth's lithosphere (the other two are magmatic rocks and metamorphic rocks).

The distribution range of terrestrial sedimentary rocks is smaller than that of marine sedimentary rocks. The distribution of sedimentary rocks outside the basin may be preserved, and the distribution of sedimentary rocks in the basin is smaller than the distribution of sedimentary rocks in the basin or the extent that can be preserved.

The world's known oil fields of a certain size are found in sedimentary rock distribution areas. Oil, natural gas and coal are formed and mostly gathered in sedimentary rocks, which can be transported thousands of meters in sedimentary rocks, and the laws of oil generation, cloud migration, aggregation and accumulation can be understood and exploited according to these traces. Sedimentary rocks related to organic mineral deposits such as oil, natural gas, coal, etc

Clastic and carbonate rocks.

The main aspects of oil exploration are:

1. Geological method: a method to study the geological conditions, geological environment and geological action of metallogenic argument through outcropping, rock, and core dismantling and tease observation;

2. Geochemistry: sampling, analysis and testing;

3. Geophysical prospecting method: a method for judging geological structure, sedimentation and other geological phenomena caused by the difference in the physical properties of underground rocks or ore bodies to discover ore bodies, commonly used are: gravity exploration, magnetic exploration, electrical exploration, ** exploration, etc.;

4. Drilling method: oil and gas exploration wells drilled for the exploration of underground oil and gas conditions, there are 4 categories (1) parameter wells; (2) pre-exploration wells; (3) evaluation wells; (4) data wells;

**Exploration: Its principle is to artificially create a strong vibration (generally in the depths of the ground**) caused by the elastic wave propagation in the rock, when the base encounters the interface of the rock layer, it will produce a reflected wave or refracted wave, when it returns to the ground with a highly sensitive instrument to record, according to the wave propagation route and time, determine the depth and shape of the buried depth and shape of the rock interface where the reflected wave or refracted wave occurs, understand the underground geological structure, in order to find the oil and gas trap.

Most of the oil is buried deep underground. If you want to find oil, you need to drill wells. Then its geological exploration principle is to drill wells and find some oil components underneath, and then take them back for testing.

This is actually the principle of the collapse of the cover, which is a kind of chemical distillation.

Sedimentary rock.

Sedimentary rock oilfields are all controlled by a single geological structural factor found in the distribution area of sedimentary rocks, and the sum of oil and gas length in the same oil and gas production area may have one or more oil and gas reservoirs in the same area.

The development history of the oil field.

Xunfeng Prefecture, the first oilfield in North China, has established the theory of "new ancient reserves" of ancient buried hills, and is the largest carbonate oil field in China, with a stable production of more than 10 million tons in ten years and ranking in the "third oldest oil field" in ten years. Guqian Mountain has brought huge material wealth to North China, and also laid a solid cultural foundation for the spiritual culture of North China Oilfield.

In the early stage of oilfield development, the social support was weak, and it basically belonged to the undeveloped wilderness. The arduous social environment and the hard work of the workers have created an entrepreneurial culture of North China Oilfield to face difficulties and strive for self-improvement. This entrepreneurial spirit is reflected in some of the rhetoric that has been widely circulated in the war zone.

The scientific researchers said about the hard work: "Four taels of steamed bread and half a pair of sand, the North China Oilfield will take root; Thousands of miles to fight, full of pride and enthusiasm for scientific research; Set up a tent for testing, and the site is a workshop; The plugging and adjusting card is refined, and the measures increase the oil by hundreds of thousands."