Formation damage is defined an impairment to the reservoir caused by the invasion of wellbore fluids during any interval of well.

In petroleum industry, it is said that “Formation damage is an expensive headache to the oil & gas industry”.

Formation Damage

Formation Damage

Mechanical Damage

Chemical Damage

Types of Formation Damage

The formation damage that is caused by the plugging of solids or grain particles with in the pore space or throats of the formation rock which ultimately results in the impedance to the flow of fluid.

Mechanical Damage

Mechanical Damage

Injection of low salinity water into a sandstone reservoir could result in clay swelling & fines migration.

Injection of incompatible water(contains high sulphate content) & the formation water contains high concentration of calcium, strontium or barium ions.

As a result, sulphate salts of these cations will precipitate in the formation & may cause severe formation damage.

Chemical Damage

Chemical Damage

Fluid-fluid incompatibility(emulsion generation etc)

Rock-fluid incompatibility(clay swelling etc) Fines invasion & migration(particles etc) Phase trapping & blocking(water

entrapment in gas reservoirs) Biological activity

Mechanism

Invasion by drilling Partial Completion Plugging of perforations Bacterial growth Dispersion of clays (Swelling) Presence of mudcake Presence of high gas saturation around the

well bore

Causes of Formation Damage

Over the last five decades, a great deal of attention has been paid to formation damage issues for two primary reasons:

Ability to recover fluids from the reservoir is affected very strongly by the hydrocarbon permeability in the near-wellbore region

Although we do not have the ability to control reservoir rock properties and fluid properties, we have some degree of control over drilling, completion, and production operations

Preventions

Thus, we can make operational changes, minimize the extent of formation damage induced in and around the wellbore, and have a substantial impact on hydrocarbon production. Being aware of the formation damage implications of various drilling, completion, and production operations can help in substantially reducing formation damage and enhancing the ability of the well to produce fluids.