Posted on January 20, 2022

Hydraulics in Oil and Gas Operations

John Joyce
Written by

John Joyce

Posted in
Oil and Gas

Oil and gas drilling are intensive operations that require enormous amounts of energy powered by hydraulic systems.  When hydraulic units break down there can be catastrophic problems or at the very least the system will not perform to its maximum efficiency, often causing costly downtime. 

A drilling operation has thousands of flexible hose assemblies and hose fittings for many different processes throughout the system, and all are critical to successful drilling requirements.

  • The vast majority of hose, fitting and hydraulic component assemblies in O&G operate at pressures 3,000 PSI or higher.
  • A typical drill rig or gas operation can have as many as 1,000 to 3,000 hydraulic hose assemblies, and it only takes one failure in the wrong place to shut-down the complete operation.
  • Improper hose and fitting selection or assembly can cost an offshore or land rig a significant amount of downtime and money, and the environmental impact can be disastrous causing significant delays that could overrun the value of the operation.

Don’t Mix and Match Components

It’s vital to use the same manufacturer for all hydraulic fitting, adapter, and flange components. Using fitting components from different manufacturers can introduce an unpredictable variable, for instance there may be a marginal discrepancy in size that appears to fit but can cause failure. It is also important to use hose from only one manufacturer. And all components must be properly assembled to the manufacturer’s specifications.

Hydraulic Rigs in Oil Field Applications

Hydraulic rigs are multipurpose units with a wide variety of applications in oil fields, with the ultimate purpose to aid in drilling. They are used in a number of circumstances including:

  • Well Control - using barriers to prevent hydrocarbons from flowing to the surface.  Well control is the prevention of the uncontrolled underground flow or releases of wellbore fluids to the external environment. 
  • Workovers – are a well intervention technique that is used to install or remove pipes in and out of dead wells (a well which has mud in the wellbore, a heavy fluid, is not capable of sustaining natural flow or has zero surface pressure). 
  • Recompletions – where well pressure is capable of increasing rapidly causing the unit to reach full snubbing capability. 
  • Well Service - is corrective work performed on an oil or gas well for improvement of production or general maintenance. 

The Importance of Hydraulic Oil

Hydraulic oil is a non-compressible fluid used to transfer power within hydraulic equipment and machinery when drilling for petroleum and accomplishes a wide variety of functions for the system. It lubricates components, dissipates heat, removes contaminants, and most importantly delivers the power needing in drilling applications. Hydraulic oils contain special additives that allow the system to withstand extreme temperatures, high and fluctuating pressures, and other conditions. As the oil travels through the system contaminants are removed when passing through a filter or dispensed into a reservoir. The life of the hydraulic system is primarily equal to the life of the oil. As long as the hydraulic oil is kept clean, and generally remains under 140°F (60°C), the system should experience less need for maintenance and a reduced need to flush the system and replace the oil. This reduces downtime and added costs, as well as helps to maintain a safe operation.

Viscosity and Lubricity

As hydraulic oil helps lubricate the system it maintains a protective film on metal surfaces which prevents the friction that can lead to the generation of heat and excessive wear.

Because hydraulic oil has a dual purpose of power transmission and lubrication it’s important to ensure the proper viscosity. Viscosity is the opposition to flow. Hydraulic oil has a higher viscosity at low temperatures and a lower viscosity at high temperatures. Since drilling often takes place in extreme climates throughout the world, it’s best to switch to a lower viscosity oil or add a specified thinning agent in cold environments.

Hydraulic Hose Should not be Confused with Drilling Hose

Unlike typical hydraulic hose, oilfield drilling hose or rotary drilling hose, is a hollow, thin-walled, steel or aluminum alloy piping. It allows for drilling fluid to be pumped down the hole through the bit and back up the annulus of the oil well (the space between two concentric objects). Drilling hose can be any of a variety of sizes, wall thicknesses, and strength depending on the specific use, but is typically 27 to 32 feet long, and sometimes as long as 45 feet.

Oilfield drilling hoses have many applications in oil & gas drilling. In conjunction with the drill pipe, a drilling mud is injected into the well at a very high pressure, most often a hydrogel solution, technical water, or sometimes a clay-based solution. They are also used between oil tankers and in sea drilling and can be found on both stationary and mobile drilling rigs. Drilling hose is also used for damping vibration applications where it is made of smaller lengths to function as a compensator.

Learn more about hydraulics by visiting Brennan University:

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