Casing & Tubings

Overview

Our casing and tubing pipe are manufactured according to API grades and also in proprietary grades including sour, high collapse, chrome and CRA products for special applications. Our proprietary grades allow us to offer the best solutions for each customer-s particular well conditions. All of our products are manufactured to the most exacting quality standards. We hold a global ISO 9001 registration for our operations, which follow a uniform quality policy and apply a rigorous quality management system.

• Maintain borehole stability
• Prevent contamination of water sands
• Isolate water from producing formations
• Control well pressures during drilling, production, and work over operations

Casing provides locations for the installation of:

• Blowout preventers
• Wellhead equipment
• Production packers
• Production tubing

The cost of casing is a major part of the overall well cost, so selection of casing size, grade, connectors, and setting depth is a primary engineering and economic consideration.

Casing strings There are six basic types of casing strings:

Conductor casing:
Conductor casing is the first string set below the structural casing (i.e., drive pipe or marine conductor run to protect loose near-surface formations and to enable circulation of drilling fluid). The conductor isolates unconsolidated formations and water sands and protects against shallow gas. This is usually the string onto which the casing head is installed. A diverter or a blowout prevention (BOP) stack may be installed onto this string. When cemented, this string is typically cemented to the surface or to the mud line in offshore wells.

Surface casing:
Surface casing is set to provide blowout protection, isolate water sands, and prevent lost circulation. It also often provides adequate shoe strength to drill into high-pressure transition zones. In deviated wells, the surface casing may cover the build section to prevent key seating of the formation during deeper drilling. This string is typically cemented to the surface or to the mud line in offshore wells.

• Intermediate casing
• Intermediate casing is set to isolate:
• Unstable hole sections
• Lost-circulation zones
• Low-pressure zones
• Production zones

It is often set in the transition zone from normal to abnormal pressure. The casing cement top must isolate any hydrocarbon zones. Some wells require multiple intermediate strings. Some intermediate strings may also be production strings if a liner is run beneath them.

Production Casing:
Production casing is used to isolate production zones and contain formation pressures in the event of a tubing leak. It may also be exposed to:

• Injection pressures from fracture jobs
• Down casing, gas lift
• The injection of inhibitor oil

A good primary cement job is very critical for this string.

Liner:
Liner is a casing string that does not extend back to the wellhead, but is hung from another casing string. Liners are used instead of full casing strings to:

• Reduce cost
• Improve hydraulic performance when drilling deeper
• Allow the use of larger tubing above the liner top
• Not represent a tension limitation for a rig

Liners can be either an intermediate or a production string. Liners are typically cemented over their entire length.

Tubing:
Tubing is the conduit through which oil and gas are brought from the producing formations to the field surface facilities for processing. Tubing must be adequately strong to resist loads and deformations associated with production and work overs. Further, tubing must be sized to support the expected rates of production of oil and gas. Clearly, tubing that is too small restricts production and subsequent economic performance of the well. Tubing that is too large, however, may have an economic impact beyond the cost of the tubing string itself, because the tubing size will influence the overall casing design of the well.

Properties of casing and tubing:
The American Petroleum Inst. (API) has formed standards for oil/gas casing that are accepted in most countries by oil and service companies. Casing is classified according to five properties:

• The manner of manufacture
• Steel grade
• Type of joints
• Length range
• The wall thickness (unit weight)

Specifications of casing and tubing Pipe

• API 5CT latest edition
• OCTG from 1.660- to 30- + respective couplings, crossovers and pup joints
• API Grades from H40 to Q125 and 13% CR
• ALL API Standard Weights
• API and Premium Joint Connections
• Special SS and HC grades
• CRA Grades

Seamless & Welded Standards:
API Specification 5CT latest edition at time of manufacture (PSL-1, PSL-2, PSL, 3)-ISO 11960:2004 – Petroleum and Natural Gas industries – Steel pipe for use as casing or tubing for wells Sizes: Outside Diameter: 1.660- – 30- Grades: H40, J55, K55, N80,N80Q, L80, C90, C95, T95, P110, Q125, SS95, SS110, 9%CR, 13%CR Connections

• STC (short round thread casing)
• LTC (long round thread casing)
• BTC (buttress thread casing)
• XL (extreme-line casing)
• NUE (non-upset tubing)
• EUE (external upset tubing)
• IJ (integral joint tubing)
• Premium Connections
• And almost any premium & gas tight connection

Protection:

• External bare and uncoated or externally coated with black/ transparent anti rust Mill varnish-Plastic or Metal Pin and Box Protectors.
• Internal plastic coating or sleeves.

Mill Test Certificates: Issued in accordance with API Specification. Additional Third Party Inspection can also be performed on request.