2009IADC, Regulation, and LegislationJanuary/February

Aging derricks could be a major problem for worldwide well servicing fleet

Guest Editorial – Joe Eustace, Pioneer Production Services

The average age of the worldwide well servicing rig fleet is over 25 years old, and many of these rigs are much older. The idea of using 25- to 30-year-old equipment seems ludicrous in most industries, yet there are still more rigs working today over 25 years of age than there are under age 10.

From 1982 until 2003, almost no new drilling or well servicing rigs were built. From 2004 to 2008, quite a few newbuilds were added to both fleets, yet very few old rigs were retired. Now, rig orders for 2009 and beyond are being canceled daily, leaving this vital industry in much the same shape as before.

Bottom line is, our well servicing fleet continues to get older every day, and we will continue to see more and more mast failures if we do not increase the depth and frequency of our API RP-4G inspections.

In 2001, API RP-4G was revised in response to the problem of aging and deteriorating derricks in the US well servicing fleet. It was determined that inspection and repair of aging derricks was the No.1 technical issue affecting our rigs all over the country. A committee was formed consisting of several US well servicing contractors and manufacturers who worked to improve the language involved with API RP-4G. Here are the highlights:

Category I

Visual observation of the mast/derrick and substructure by rig personnel during operations for indications of inadequate performance.

Category II

Scope: Category I inspection plus a more thorough inspection of, but not limited to, load-bearing areas and sheaves for cracks, damage, corrosion, loose or missing components and premature wear. This more detailed inspection should be performed during rig-up operations.

Qualifications: Personnel undertaking Category II inspections will be individuals designated by the owner company who have adequate experience and knowledge in masts. These individuals will typically be experienced field superintendents, engineers, rig supervisors, rig operators or operations managers.

Category III

Scope: A thorough visual inspection of all load-bearing components and members should be conducted to determine the condition of the mast, derrick or substructure and documented. Inspections on well servicing, truck- or trailer-mounted masts should include observation of rig-up/rig-down operations.

Qualifications: The individual supervising the Category III inspection must possess adequate knowledge and experience. Typical qualified persons would be an engineer, an NDT technician, an ASNT Level II Technician, or a senior service operations person, designated by the owner company or others, provided they meet the criteria of experience, training and knowledge.

Documentation: The completed (and signed) checklist and any major repairs are to be documented in the permanent rig file.

Category IV

Scope: A Category III inspection plus the equipment to be disassembled and cleaned to the extent necessary to conduct NDT of all critical areas. An ultrasonic thickness test is recommended on all tubular style (or closed style) members to test for internal corrosion. Internal cameras, usually run on cable, may also be used to visually inspect for internal corrosion. All welds (100%) shall be visually examined. All welds in critical areas shall be inspected using the magnetic particle (MPI) or liquid penetrant (PT) method in accordance with Section 6 of AWS D1.1.

Qualifications: The Category IV inspection should be conducted by, or closely supervised by, a certified associate welding inspector (CAWI) or higher certification, professional engineer or an original equipment manufacturer (OEM) representative. In addition, Category IV inspectors should have previous experience and satisfy the requirements of Category III inspectors. NDT inspectors for a Category IV inspection would be required, as a minimum, to have certification as an ASNT Level II Technician.

Personnel performing visual inspection of welds shall be qualified and certified as an AWS-certified welding inspector, or an engineer or technician who, by training or experience, or both, in metals fabrication, inspection and testing, is qualified to perform inspection of the work.

Overall: Welders on derrick and mast repairs must be certified by an independent laboratory in accordance with AWS D1.1 and should have experience in mast maintenance. All welding completed should be in accordance with the requirements of AWS D1.1.

Documentation: In addition to the documentation requirements above, the 4G recommends that “the user/owner shall maintain an equipment file containing pertinent information regarding the mast and substructure. The file should include the following: Records of Category III and Category IV inspection shall be entered in the equipment file related to or indicating the load-carrying capacity of the mast and substructure. Entries describing repair, modification and testing activities shall be included in the owner equipment file.” Beyond this explanation, the specific information we recommend be maintained in the rig file is identified on a line-item basis.

Anchors: One of the most important pieces of the API 4G is the language surrounding the use of temporary anchors. It states that “screw-in anchors will be installed and verified utilizing a mechanical method (pull tested or shear torque method).” This means manual screw in anchors put down with a post hole digger, and four very tired rig hands will not do. In addition, it clearly identifies the responsibilities of the operator, contractor and the anchor-testing company in order to minimize the potential for accidents in this area.

“The rig contractor shall be responsible for:

•  Ensuring that anchor capacities are verified prior to attaching guywires to the anchors, that the verification is less than 24 months old and that anchor spacing and capacity is suitable for the mast guying pattern and anticipated loading.

•  Maintaining all guywires and end terminations in good working condition.

•  Inspecting anchors for damage or deterioration prior to rigging up.

•  Inspecting surface ground conditions that might indicate reduced anchor capacity.

•  Properly aligning the rig in relation to the wellhead and anchors.

•  Placing a visible marker on each guywire.

•  Replacing soil around anchor.

The wellsite owner/operator shall be responsible for:

•  Installing anchors at each well site.

•  Providing anchor capacity verification.

•  Replacing anchors that are damaged or excessively deteriorated or that fail anchor capacity verification.

•  A permanent file record for anchors that are installed or tested shall be maintained. The file should include dates of installation, each capacity verification, pull test charts and the name and telephone number of the party conducting the capacity verification.

•  Placing a visible marker on each anchor furnished, installed or specified by the well site owner/operator.”


A derrick failure can be a catastrophic event in terms of equipment damage, lost revenues and far more importantly, human life. Our industry needs to pay much closer attention to maintaining and inspecting our masts and load-bearing structures before it’s too late.

Joe Eustace is president of Pioneer Production Services and chairman of the IADC Well Servicing Committee.

Related Articles

One Comment

  1. These decisions and programs are perfect and should avoid accident and failures.
    The most important issue is ,in the oil drilling industry,who should put in force these programs.
    To my humble knowledge the Oil Operating Co’s ,who are the most at risque ,in such cases should add in their contract with the drilling contractors this matter and require that the inspection co’s would deliver a report copy directly to them.

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button