Method of Supporting a Subterranean Conduit

Abstract

A method and apparatus for consolidating a formation penetrated by a wellbore utilize radial stress. The radial stress is created by loading the wellbore, wellbore casing or production pipe with preferably round, dense bead like materials. The shape and density of the bead like material transfers the axial direction of stress created by the vertical height of the bead like materials to a radial direction. The radial stress can also be generated by inflating an inflatable device. The radially directed stress can compact the geologic formation. This can include compaction of loose sand which otherwise may enter the production flow of hydrocarbon. The bead like materials can also support the wellbore casing or production piping from point loading. This can include point loading created by the movement of salt or other subterranean formations. The bead like materials can include barite, hematite, iron oxide, ilmenite, metal, alloy and combinations thereof.

Description

FIELD OF INVENTION[0001]A subterranean wellbore, perforation hole, any tube, including casing, or tubing inside the wellbore or casing, can be called a subterranean conduit. These conduits are often under stress or pressure and, in some conditions, these conduits are not strong enough to withstand the stress or pressure. The conduits may fail and generate other problems, including interruptions of hydrocarbon production. This invention provides a method to provide a substantial radial stress to a subterranean conduit high enough to support the conduit to prevent its collapse or the collapse of a wellbore, casing or tubing. It also prevents sand production, prevents closure of a hydraulic fracture for hydrocarbon production and prevents or closes a micro-annulus. The provided radial stress is substantially uniform radially around a subterranean conduit to best support the conduit.[0002]During the production of hydrocarbon, the pressure of a well at a wellbore location and the pressur...

AI Technical Summary

Benefits of technology

This patent describes a method for supporting a subterranean conduit, such as a wellbore casing or tubing, that may be damaged or have a micro annulus formed. The method involves placing bead-like materials into the conduit to form a packing that provides uniform and radial support. The bead-like materials can conform to the wellbore wall and can transfer axial or vertical stress to radial stress. The method can also involve applying additional radial stress to the packing to further support the entire active zone of the conduit and prevent damage or collapse. The force can be applied through inflatable devices, such as close-ended rubber tubes, or by adding weight or using a spring, pressurized fluid, or elastic force acting on the packing. The technique allows for better protection and preservation of the conduit during production.

Problems solved by technology

The production of formation sand into a well has been a problem plaguing the oil and gas industry.

It has an adverse effect on well productivity and equipment.

But it can plug wells, erode equipment and settle in surface vessels.

Controlling formation sand is costly and usually involves slowing the production rate in some way.

Though the conventional methods of sand control can enable production for some extended time, failures can be observed from time to time.

Repairing a well may have a huge direct cost plus a loss of production.

These devices may not last for long due to erosion from sand grains.

Furthermore, the retaining screens or slotted liners are a two-dimensional filtering mechanism and tend to be plugged and production therefore is compromised.

However, even in most of gravel packs, a finite quantity of solids is still produced.

Due to the damage to the formation or to the gravel packing during operations, the production of hydrocarbon may suffer from a so called “skin” effect.

This means extra flow resistance is created by either the formation damage or the gravel packing damage.

During sand production, some gravel packing may be displaced by formation sand and exposing screens directly to sand causing erosion of the screens.

These voids 11 may cause subsidence and the well will eventually fail.

However, after some sand fines are produced, the formation near the wellbore behind the casing will become loose and sand production will be worsen quickly.

It is obvious that, even with cased hole gravel packing, the above mentioned problems can still occur.

Otherwise, the wellbore may soon collapse.

It has been difficult to ensure all the rock around a wellbore is consolidated evenly so that no channels that can produce sand are left.

Casing or tubing may burst when the pressure inside the casing or tubing is too high.

Salt formations may be plastic and cannot support its overburden above it and may slowly deform over a long time under pressure and temperature.

Such encroachment onto casing generates point loading.

The point loading is getting higher over time and may eventually collapse the casing.

There have been no good solutions so far.

This can cause severe compaction of the formation and induce subsidence.

Either compaction or subsidence may cause the casing to buckle or collapse and the well to fail.

Adapting the shrinkage of a formation thickness has been very challenging.

However, such casing is very weak for containing pressure.

However, the long-term sealing between the two sets of casing is difficult to maintain due to the movement under downhole high pressure and high temperature conditions.

During production, hydrocarbon or other fluid may leak into the annulus around casing or tubing through failed cementing sheath causing the pressure in the annulus to increase.

When the annulus pressure is high enough, it can collapse the casing or the tubing.

Due to these high loadings, even strong and thick wall casing may not be a good solution to casing collapse.

These valves may malfunction.

This reduction of pressure will cause the casing to shrink.

This shrinkage may cause the casing to debond or separate from cement sheath around the casing.

In a severe condition, the normally required pressure isolation from cement will fail.

A micro-annulus is a very tiny space and it is very difficult to pump a material such as cement to regain the sealing or the pressure isolation.

When the fracture pressure is too low, eventually, the fractures can close and the production rate can drop dramatically.

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