What is perforation in oil field?

Perforating is a process used to establish a flow path between the near reservoir and the wellbore. It normally involves initiating a hole from the wellbore through the casing and any cement sheath into the producing zone.

What is a perforation gun?

The primary objective of a perforating gun is to provide effective flow communication between a cased wellbore and a productive reservoir. • To achieve this, the perforating gun “punches” a pattern of perforations through the casing and cement sheath and into the productive formation.

Why do we need a perforation in oil and gas wells?

You need to perforate the casing and do the appropriate amount of damage to the surrounding formation – too much damage can create excess debris (which can cause problems with downhole operations) and not enough can limit your productivity.

How is perforation done?

The process of perforation involves lowering a perforating gun into a wellbore to a planned depth and energizing the gun to be safely fired. When perforating a well, shape charges are fired and then energy from the explosion will create tunnels through casing, and cement and then into a reservoir.

What is perforation and its types?

 There are four main types of perforating guns:  Wireline conveyed casing guns  Through-tubing hollow carrier guns  Through-tubing strip guns  Tubing conveyed perforating guns. 21. Wireline Conveyed Casing Guns Generally run in the well before installing the tubing.

What does perforation mean in medical terms?

Perforation is a hole that develops through the wall of a body organ. This problem may occur in the esophagus, stomach, small intestine, large intestine, rectum, or gallbladder.

What is underbalanced perforation?

1. vb. [Perforating] To create holes in the liner or casing under conditions in which the hydrostatic pressure inside the casing or liner is less than the reservoir pressure. When the perforation is made, there will be a tendency for the reservoir fluid to flow into the wellbore.

What is perforation rate?

Results: The frequency of perforation was found to be 1 in 1400 for overall colonoscopies and 1 in 1000 for therapeutic colonoscopies. Varying perforation rates have been estimated for polypectomies, endoscopic mucosal resections, and endoscopic submucosal dissections.

What are signs of bowel perforation?

Symptoms of a bowel perforation include:

  • sudden and severe abdominal pain.
  • nausea and vomiting.
  • fever.
  • chills.
  • swelling and bloating of the abdomen.

Is perforation same as rupture?

Rupture of appendix: A break or tear in the appendix, usually due to appendicitis. Also called perforation of the appendix. Rupture of appendix can lead to a periappendiceal abscess (a collection of infected pus) or diffuse peritonitis (infection of the entire lining of the abdomen and the pelvis).

How does a perforation gun work in an oil well?

In Tubing Conveyed Perforations the system consists of a casing perforating gun run into the well at the bottom of a string of production tubing or drill pipe. The perforating gun can be assembled for any required length and shot density. Depth control is obtained by running a GR and CCL tool.

What are the parts of a downhole perforating gun?

The downhole perforating assembly of a horizontal well includes generally a locator sub, detonating device, underbalance accessories, packer, oriented perforating gun, centralizer, and ball guide shoe.

How is the detonation energy of a perforating gun transmitted?

Both ends of the interbed gun are plugged by using a baffle fire workpiece. The detonation energy of the perforating gun is reliably transmitted to the perforating gun below the interbed gun through the baffle detonation-transmitting device.

What kind of firing head does a perforating gun use?

Pressure activated firing—tubing conveyed guns can be fired using pressure activated firing heads. Most have an integral time delay with a predetermined duration between the application of pressure and gun detonation. Wellsite supervisors need to know how the firing head selected for any perforating operation works.