What is oil layer casing?
Oil layer casing, also known as production casing. It is the last layer of casing in the oil and gas well casing program, running from the wellhead to below the oil and gas layer it passes through. The depth to which the oil layer casing is driven is basically the depth of the well.
What is the function of oil layer casing?
The function of the oil layer casing is the channel for oil and gas to reach the ground, isolating the oil and gas from the entire formation, and ensuring that the oil and gas pressure does not leak. After the oil and gas well is transferred to production, the quality of the oil layer casing must be guaranteed to maintain a certain production life.
The main functions of oil layer casing are as follows:
1. Support oil and gas well walls: ensure the smooth progress of the drilling process and ensure the normal operation of the oil well after completion.
2. Oil and gas channel: Isolate oil and gas from all other formations, keep oil and gas pressure stable and avoid leakage.
3. Separate layers: Effectively distinguish production layers from other strata to prevent oil, gas and water layers with different pressures from colluding with each other.
4. Convenience of perforating: It is convenient to perform perforating operations in the oil layer.
5. Layering operation: It helps to carry out layering operation and improve drilling efficiency.
6. Well wall reinforcement: Reinforcing the well wall of the oil layer through cement sealing and other methods is crucial for both exploration wells and production wells.
7. Well control equipment support: Provide necessary conditions for the installation of wellhead devices, blowout prevention, leakage prevention and hanging liner, and have a protective effect on the oil layer casing.
8. Isolate unstable strata: Prevent unstable, loose, prone to collapse, and prone to leakage strata and water layers in the upper layer from affecting the stability of the well wall.
9. Directional well safety: When the well deviation is large, help the directional well drill safely and run technical casing in the deflection section.
The cementing quality of oil layer casing is related to the exploration well on the one hand and is the key to oil and gas testing; on the other hand it is related to the production well and directly affects the life of the well. The cement sealing height of the gap between the oil layer casing and the well wall shall be at least 500 meters above the oil and gas layer, or up to 200 meters within the upper casing.
In summary, oil layer casing plays a key role in maintaining the normal operation of oil wells and ensuring the effective development of oil and gas resources.
Expanded information:
The function of oil casing pipe is a steel pipe used to support the well wall of oil and gas wells to ensure the normal operation of the entire oil well during the drilling process and after completion. Each well uses several layers of casing based on different drilling depths and geological conditions. The specific functions of the pipe sleeve are as follows:
1. Surface casing: Install the casing head on the top, and suspend and support subsequent layers of casing through the casing head; isolate the surface shallow water layer and the shallow complex bottom layer to prevent the fresh water layer from being polluted by drilling fluid.
2. Intermediate casing: isolates layers with different formation pressures or complex formations that are prone to collapse and leakage.
3. Production casing: protects the production layer and provides a channel for oil and gas to flow from the production layer to the ground.
4. Drilling liner: Reduce the load on the drilling rig when running casing and the load on the casing head after cementing, while saving a large amount of casing and cement and reducing cementing costs.
