Introduce of A Packer
A packer is a common down-hole tool used in oil and gas fields. They are primarily used to separate the upper and lower sections of a well-bore, creating an independent, sealed space for operations such as fracturing, acidizing, water injection, and testing. They act like a "plug," capable of withstanding high pressure and effectively sealing the well-bore annulus.
Main Functions:
Isolate well sections,
Divide the well-bore into sections to facilitate independent treatment of each section.
Control fluid flow,
Prevent fluid cross-flow during injection or production,
Seal and pressure bearing,
Withstands high-temperature and high-pressure environments of the down-hole and maintains a sealed state,
Assist in well testing and measurement,
Creates an independent pressure environment in the well-bore to facilitate flow or pressure measurement.
Common Classifications
By Structure
Mechanical packer: It is sealed by mechanical actions such as lowering, rotating and lifting.
Hydraulic packer: It relies on the pressure of the liquid underground to push the rubber cylinder to set and seal, and is easy to operate.
Retrievable Packers: Can be unsealed and retrieved after operation, suitable for testing and temporary operations.
Disposable Packers: Non-retrievable after setting, often used for permanent isolation.
By Application
Well Test Packers: Used for oil and gas well testing, isolating reservoirs, and obtaining pressure data.
Fracturing Packers: Suitable for staged fracturing, resistant to high pressure and high temperature.
Water Injection Packers: Used for selective water injection into injection well sections to prevent cross-flow.
Sand Control Packers: Used in conjunction with sand control strings to prevent sand from entering the well-bore.
Main Structure
Rubber: A key component of the packer, expanding under pressure to conform to the well-bore.
Setting Mechanism: Controls the deployment and retraction of the packer (mechanical or hydraulic).
Pressure-Bearing Component: Withstands down-hole pressure and ensures a reliable seal.
Connector: Connects to the tubing and test string.
Applications:
Stage fracturing: Often used in groups during multi-stage fracturing operations in horizontal wells.
Oil well testing: Obtaining single-layer productivity data.
Water injection wells: Implementing stratified water injection in different strata.
Gas well and shale gas development: Used for multi-stage fracturing and testing.
