Types of drilling fluids

 

 

The drilling fluid plays several essential functions in drilling wells. One of these functions is the (mud weight). Which is very important to calculate the hydrostatic pressure.

We know that the drilling fluid is the most important element in the drilling engineering whish has a lot of function in the drilling these function can solve a lot of problem that exist in the drilling wells .

Mud weight is the weight of substance per unit volume control the formation pressure.

There are a lot of substance can be add in the mud to increase or decrease the weight of mud to equalize the pressure of the formation.

In Libya we use some substance like (barite) and (Calcium carbonate) these two substance are adding in the mud to increase the weight of mud to  equalize the pressure of the formation  to prevent the kick and blow out during the drilling but we must to know when we used these substance , for example the barite does not use in the productive zone.

Because it is prevented the productive zone to produced the oil.

 it had some property that deposited on the porous of the formation and reduction the permeability of the strata of production and the (calcium carbonate) is used in productive zone ti prevent the invasion in the strata.

 

 

Global Drilling Fluid Types

Water-Base

-Water as continuous phase

-Include sbrines and miscible materials

-No emulsions

 

Oil-Base / Synthetic-Base

 

-Oil or synthetic as continuous phase

-Water (brine) droplets emulsified into

-oil / synthetic

 

Air / Mist / Foam

-Used for hard, dry rock drilling

-If water influx, switch to WBDF or OB-DF

 

 

Water-Base Drilling Fluids

Examples of Bentonite-Base Drilling Fluids

- “Spud” mud

- Freshwater deflocculated bentonite

-Seawater deflocculated bentonite

- Bland coring fluid

- Lime-base bentonite

- Gyp-base bentonite

 

Oil-Base / Synthetic-Base Drilling Fluid Types

-Diesel Oil- Base

Original “oilbase” fluid

-Mineral Oil- Base

Refined oils from diesel, often with low aromatic content

-Synthetic- Base

Recent base liquids, created in synthesis reaction

Summary

* Three major types of water-base fluids

– Bentonite clay based

– PHPA extended-bentonite based

– Polymer-brine based

* Two major types of non-aqueous fluids

– Diesel and mineral oil-based

– Synthetic-based