Vital maintenance for land-based drilling rig

Published:  20 December, 2019

While much of the world’s oil & gas supplies are to be found out to sea and extracted via offshore drilling rigs, there are also a number of land locked countries that have access to vast quantities of oil and gas. Specialist drilling rigs travel across land as a mobile wheeled fabrication. The drill is attached to the end of an extremely long hydraulic cylinder. Once in situ, the drill is manoeuvred from horizontal to upright and becomes a drill mast.

The drill is installed and the hydraulic cylinder pushes the drill into the earth as it turns. Once the drill is pushed as deep as the cylinder stroke allows, the hydraulic cylinder is retracted and the next piece of steel tube is connected to the drill, so that as the cylinder rod re-advances a further section can be dug. In this way, a depth of hundreds of metres can be efficiently drilled in the space of several weeks. Once the bore hole is complete, the process reverses, with the drill and tube uninstalled to make way for piping and pumps to extract the valuable oil or gas.

Much of the world’s landlocked oil & gas is found in extremely remote areas, such as the desert. This drilling machinery can be extremely expensive and may be taken to locations thousands of miles from its place of manufacture; a process that merits the expense due to the millions of pounds of oil or gas that the company expects to extract. Therefore, it is vital from a financial (as well as environmental) point of view, that once the drill is in situ, there is no possibility of it failing.

Because of this, it is standard for the entire drilling rig to be stripped and repaired or replaced every several years, rather than waiting for the fabrication to break before repairing it. Industry practice means that the rig is generally repaired at least every five years; although many companies will choose a full maintenance programme after each job is completed, prior to being redeployed elsewhere.

A client recently approached bespoke hydraulic cylinder manufacturer Apex Hydraulics, with a commission to repair a 9 metre-long Drillmech mast cylinder. This is a challenge, as many smaller hydraulic cylinder manufacturers and repairers are unable to work with such large cylinders. Apex has the capacity to repair hydraulic cylinder rods up to any length, using advanced machines and cranes in their top spec Dewsbury based factory.

Apex Response

The cylinder repair began with a strip and assessment in order for the expert team to analyse the repairs that were required. This is the point at which any major design flaws can be identified and redesigns can be advised. However, in this case, as expected, there was no damage to the original cylinder, other than routine issues associated with use; such as wear to seals and slight cracking and chipping to the chrome.

The rod was precision ground and re-chromed, bringing its condition back to new. The cylinder bore was honed and polished, and all seals replaced. It was then thoroughly pressure tested to industry standards. Apex re-certified the cylinder and it’s back-to-new condition ensures that it will continue to work for the next drilling campaign.

Apex reports that it can repair any cylinders from any drilling rig manufacturers, including; Tatra Trucks, Streicher, Fraste Spa, Dando Drilling, Epiroc and more.

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