Well activation overview || Petroleum Engineer

Well Activation Introduction

Well activation involves reducing hydro static head in the well. After well completion well required activating so that formation fluid will come from reservoir to well head and well is produce crude oil. We have to create negative overburden pressure in the well head, thereby inducing formation fluid into well bore. Displacing the workover fluid with lighter fluid may be sufficient to enable to well flow. However when higher draw-down is required to activate the well, one of the activation method is used. We will discuss 5 types of well activation method here.

Different Method Of Well Activation

We will discuss 5 types of well activation method briefly in this article, these are-

1. Displacement Method
2. Compression Application.
3. Application of Nitrogen.
4. Aerisation Techniques.
5. Swabbing 

 

1. Displacement Methods

• Main aim to reduce the density of completion fluid so that production will occur
• It is step by process so we can control formation fluid
• Aim is to reduce the pressure of the bottom of the well bore.
• High density fluid is displaced by some low density fluid.
• It is step by step by step process. If we decrease suddenly the fluid density, then (completion fluid density then) uncontrol influx of Hydro Carbon Occurs.
• 0.2-0.3 density sg is reduced in each step
• It is done until well is activated

 

2. Compression Application 

We compressed Gas and injected into well ( In annular space we inject high pressure gas ) – U Tube effect occur. Ps – pwf is sufficient to produce hydrocarbon.

Main aim to reduce the pressure of the bottom of the well bore. It is also step by step process.

• Compression application is not a single step process.
• Compression gas injected in to annulus.
• Packer is not put in annulus, So that we inject compression fluid.
• Gas Buddle mixes with fluid in tubing.
• Density of fluid decreases.
• Ps – pwf is sufficient to produce the well.
• Applied repeatedly until and unless well is activated.

3.  Application  of Nitrogen

 

Gaseous N2 is obtained at  350 kg per cm2. The high pressure is sufficient to displace half almost of the well. So it reduce time and man power.

Generally liquid Nitrogen is brought and pumped using “ Cryogenic pump” and converted to gaseous nitrogen.

Aim is the same as previous method

In this method we used oil tubing

Large bubble are formed.

4. Aerisation Technique

Entire liquation column density reduced, no piston effect – bubbling effect takes place, aerisation is responsible for density reduced.

Air is used. When we used air , generally gas bubble become bigger.

If displace or aerisation is not successful, N2 is used.

Under condition air compress is released. This process leads to form bubble and hence density reduced.

 

5. Swabbing

Pipe is suddenly released during tripping or pipe is suddenly withdraw,

1. Surging Pressure:- 

When drilling fluid filled , pipe is suddenly released during tripping. More pressure is generated inside the well.

2. Swabbing pressure:-

 Pressure is reduced during pulling the drill pipe, then it leads influx of fluid.

Swabbing well activation is done by swabbing tool.

 

We discuss this well activation process with further information in next articles.

 

Notes: -  I collect this article information from various university notes. Some information also collected from schlumberger and other e&p company sites.

 

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