Category Archives: Completion

Collapse Pressure Property for Oilfield Tubular

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Collapse happens when differential between external and internal pressure exceeds a collapse rating pressure of material. This situation can happen due to several cases, such as pressure testing in annulus, trapped pressure in the annulus or well fully evacuated with gas, etc.

Figure 1 - Collapse Pressure Diagram

Figure 1 – Collapse Pressure Diagram

 

Collapse pressure equations come from experiments from test specimens and the full details can be found in API Bulleting 5C3, Formulas and Calculations for Casing, Tubing, Drillpipe, and Line Pipe Properties. From the experimental results, there are 4 collapse regimes based on Diameter of pipe/Wall thickness (D/t) and yield strength of material which are yield strength collapse, plastic collapse, transitional collapse and elastic collapse. Continue reading →

Burst (Internal Yield Pressure) Property of Tubular

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Burst is a condition where internal pressure exceeds pressure loading. Burst can happen in several situations, such as well control, pressure test casing/tubing, pumping operation, etc.

Figure 1 - Burst Pressure Diagram

Figure 1 – Burst Pressure Diagram

Minimum burst rating pressure (internal yield pressure) can be calculated by the following equation.

Where;

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Important Material Properties of Tubular and Completion String

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It is imperative to understand mechanical properties of tubular because it involves the safety structure of the well. Failure in completion can cause major catastrophic problems in people safety, major loss of expenditure and loss of production from a well.

This article will describe the basic mechanical properties which are very essential to understand. Continue reading →

Basic Sand Control Methods in Oil and Gas Industry

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Sand control is a method to control sand production into a wellbore. This is common requirement for several oil and gas producing wells around the world. There are two situations which cause sand production. The first cause is rock mechanical failure near wellbore and the second one is dragging force from producing or injection fluid. Sand production can lead to several issues such as production impairment due to sand plugging, erosion to completion string and down hole tool, damage surface facilities as separator, piping, etc.

In order to avoid sand production, there are two main methods as listed below;

Passive sand control

This method uses non-intrusive measures to control, mitigate or avoid sand production from the reservoir. The following techniques are passive sand control methods.

  • Oriented perforation
  • Selective perforation
  • Sand management

Active sand control

This method relies on the use of filters to control sand production and it is known as intrusive measure. The following techniques are active sand control methods.

  • Stand alone screens (slotted liner, wire-wrapped screen, prepacked screen and premium screen)
  • Expandable sand screen
  • Gravel pack & Frack Pack
  • Chemical consolidation

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