Through the exploration of petroleum workers, we will find oil storage blocks, using special equipment and technology, drill down or side cylindrical holes of a certain diameter at the pre-selected surface location, and drill underground oil and gas reservoirs, which is called drilling.
Drilling plays an important role in various tasks of oil exploration and oilfield development. Such as finding and confirming hydrocarbon-bearing structures, obtaining industrial oil flow, proving the oil-bearing areas and reserves of proven hydrocarbon-bearing structures, obtaining geological data and development data of relevant oilfields, and finally taking crude oil from the ground to the surface, etc., all of them are accomplished by drilling. Drilling is an important link in the exploration and exploitation of oil and natural gas resources, as well as an important means of exploration and development of oil. The petroleum exploration and development process is composed of many stages of different nature and tasks. In different stages, the purpose and task of drilling are different. Some are designed to identify oil storage structures, others to develop oil fields and exploit crude oil. In order to meet the needs of different stages and tasks, the types of drilling can be divided into the following categories.
Benchmark wells: wells drilled in order to understand the sedimentary characteristics and hydrocarbon-bearing conditions of the formation, verify the results of geophysical exploration and provide geophysical parameters during the regional census stage. Generally drilling into bedrock and requiring full well coring. Profile well: a well drilled along a large regional section in a covered area. The purpose is to expose regional geological profiles, study lithology and lithofacies changes and find structures. It is mainly used for regional census. Parameter well: a well drilled in an oil containing basin for understanding regional structure and providing petrophysical parameters. Parameter wells are mainly used for comprehensive detailed investigation.
Structural wells: wells drilled in order to compile a structural map of a standard underground layer, understand its geological structure characteristics and verify the results of geophysical exploration. Exploration wells: wells drilled in order to determine the existence of oil and gas reservoirs, delineate the boundary of oil and gas reservoirs, conduct industrial evaluation of oil and gas reservoirs and obtain the geological data needed for oil and gas development within the favorable oil and gas accumulation structures or oil and gas fields. The wells drilled at each exploration stage can be divided into pre exploratory wells, exploratory wells, detailed exploration wells, etc. Data wells: wells drilled for the purpose of compiling oil and gas field development plans or obtaining data for some special studies during the development process. Production well: a well drilled for the exploitation of oil and natural gas when developing oil fields. Production wells can be further divided into production wells and gas production wells.
Water (gas) injection wells: wells drilled by injecting water and gas to supplement and rationally utilize formation energy in order to improve oil recovery and development speed. The well drilled specially for water injection and gas injection is called injection well or gas injection well, sometimes referred to as injection well.
Inspection wells: wells drilled in order to understand the pressure and distribution of oil, gas and water in each reservoir, the distribution and variation of remaining oil saturation, and the effect of various adjustment measures for tapping potential. Observation wells: wells that are specially used to understand the underground dynamics of oil fields during oilfield development. Such as observing the pressure of various reservoirs, the law of water cut change and the law of single layer flooding, etc. It generally does not bear the production task. Adjustment wells: In the middle and late stages of oilfield development, wells drilled by the original development pattern (including production wells, injection wells, observation wells) are adjusted to further improve the development effect and ultimate recovery. The reservoir pressure of such wells is either low pressure in the later stage of oil production or high pressure due to the energy preservation of injection wells. In the development of the whole oilfield, there are several stages of exploration, construction and production, each stage is related to each other, and a lot of drilling work is needed. High quality, fast and efficient drilling is an important means of oilfield development.