engineering

Production tubing

Production tubing is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Production tubing rather than just read about it. In short: Production tubing is a tube used in a wellbore through which production fluids are produced (travel). Background Production tubing is run into the drilled well after the casing is run and cemented in place.

Key takeaways

Production tubing belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Production tubing to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Production tubing from memory before moving on to harder problems.

Reference excerpt

Production tubing is a tube used in a wellbore through which production fluids are produced (travel).

Background Production tubing is run into the drilled well after the casing is run and cemented in place. Production tubing protects wellbore casing from wear, tear, corrosion, and deposition of by-products, such as sand / silt, paraffins, and asphaltenes. Along with other components that constitute the production string, it provides a continuous bore from the production zone to the wellhead through which oil and gas can be produced. It is usually between five and ten centimeters in diameter and is held inside the casing through the use of expandable packing devices. Purpose and design of production tubing is to enable quick, efficient, and safe installation, removal and re-installation. If there is more than one zone of production in the well, up to four lines of production tubing can be run.

Production casing Production casing is the final casing string set in a well and usually reaches from the surface to Target Depth (TD). The type of casing used depends upon the different conditions in the well. Commonly, production casing sizes range from 4+1⁄2 in (110 mm) to as large as 9+5⁄8 in (240 mm). It is the last string cemented in a well unless a production liner is run. This casing isolates production in the well so that different intervals can be selectively perforated and produced. Usually, the lower zones of production are perforated first. The formations are depleted, those perforations are squeezed with cement and the casing perforated above the original perforations. The production is usually brought to the surface through tubing. Tubing is a smaller diameter pipe that is run inside of the production casing. A packer is usually set at the lower end of the casing to prevent formation fluid from entering the annulus between the tubing and the casing. A packer is an elastomer cylinder that forms a pressure seal between the tubing and the casing. Obviously, good cement placement is required in the production interval. Flow behind the casing from the production zone to a barren formation can prevent production of a large quantity of hydrocarbon.

Production liner A production liner is a string of casing set across a production interval but does not extend all the way back the surface. Usually there is about a 500 ft (150 m) (more or less) overlap between a liner and the casing string above. The production liner has the same function as a complete string of production casing. A typical casing arrangement in a well is shown in the diagram below. In this case, the surface casing is set to a depth of about 3,000 ft (910 m). Two intermediate strings are set in this well — a 13+3⁄8 in (340 mm) string and a 9+7⁄8 in (250 mm) string. A 7+5⁄8 in (190 mm) production casing is set at a depth of about 15,000 ft (4,600 m) and a 5 in (130 mm) production liner set to TD. Probably, this well required a high mud weight at the bottom of the hole and cementing the 7+5⁄8 in (190 mm) casing at TD would have resulted in too much pressure and lost circulation. If lost circulation occurs during a primary cement job, there is little guarantee that cement will fill the designated volume behind the casing. This will require the casing be perforated and cement squeezed into the casing/well bore annulus.

Worked examples

Example 1 — a first encounter with Production tubing

Start with the simplest possible case. Write down what Production tubing claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Production tubing before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Production tubing ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Production tubing

In research: Production tubing appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Production tubing in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Production tubing is common in secondary-school and first-year university syllabi. It links to neighbouring topics Oil wells, Petroleum production, Tubing (material), so understanding it makes those chapters shorter.
In everyday life: Look for Production tubing outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Production tubing in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Production tubing means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Production tubing out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Production tubing in simple terms?

Production tubing is a tube used in a wellbore through which production fluids are produced (travel). Background Production tubing is run into the drilled well after the casing is run and cemented in place.

Why does Production tubing matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Production tubing?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Production tubing.