Mud Cake / Filter Cake Cleaner – OLKLIN-MCC-1

OLKLIN®-MCC-1

MUD CAKE / FILTER CAKE CLEANER

Description:

OLKLIN^®-MCC-1 liquid blend contains surfactant, chelating agents, corrosion inhibitors in a suitable solvent and is used primarily as an aqueous wash composition suitable for the clean-up of drilling and completion fluid filter cakes. The product OLKLIN^®-MCC-1 relates to the construction of wells, and more particularly to the clean-up of drilling and completion filter cakes or other well reservoir damages. The product is preferably used for wellbore completion process.

Background:

In the process of rotary drilling a well, a drilling fluid or mud is being circulated down the rotating drill pipe, through the bit, and up the annular space between the pipe and the formation or steel casing, to the surface. The drilling fluid performs different functions such as removal of drilled cuttings from the bottom of the hole to the surface, suspension of cuttings and weighting material, control of subsurface pressures, maintaining the integrity of the wellbore until the well section is cased and cemented, isolate the fluids from the formation by providing sufficient hydrostatic pressure to prevent the ingress of formation fluids into the wellbore, cool and lubricate the drill string and bit, maximise penetration rate etc.

For all fluid types, there is desirable to minimise the permeability damage in drilling reservoir formations when in fact, during the operations for drilling and completing hydrocarbon-bearing formations (reservoirs), an overbalance pressure is often applied which causes fluid loss from the wellbore into the reservoir rock. This filtration process causes build-up of a low permeability filter cake, comprised of the solid phases present in the fluid. The presence of this cake can be detrimental to the production of hydrocarbons from the reservoirs.

It is well known to use wash fluids to break-up and dissolve (wholly or partly) the filter cake. The fluids used to drill and complete the reservoir are generally polymer solutions with various additives including calcium carbonate, clay and salt. The polymer solutions are typically comprised of one or more of the following: bio-polymers (Xanthan etc.), starches and celluloses (hydroxyethyl cellulose[HEC], polyanionic cellulose [PAC]). The filter cakes are therefore comprised of these components, plus drilled solids picked up during the drilling phase.

It is preferable to remove as many of these components as possible from the filter cake which has built up on the producing formation.

Our product OLKLIN^®-MCC-1 is particularly advantageous in the sense that there are a number of problems associated with using hydrochloric and organic acids for the carbonate removal, these include health, safety and environment issues, corrosion issues and placement issues of the acid across the wellbore interval to be treated. Laboratory tests have also shown that the acids can be damaging to the reservoir rock matrix. On the other hand, OLKLIN^®-MCC-1 has been shown to be superior in terms of safer health, safety and environment issues, low corrosion rates, flexible placement chemistry and low levels of formation damage.

The product can be used for cleaning filter cakes not necessarily containing carbonate. The inbuilt property of OLKLIN^®-MCC-1 also prevent the re-precipitation of inorganic salts, such as iron compounds, which can also be damaging to the overall productivity of the reservoir. The product is essentially useful for treating the reservoir zone prior to producing. Another application is for remedial treatment, for instance to clean gravel. In this latter case, the clean-up fluid can be used in a gelled form, well appropriate to treat a small zone of the wellbore.

The pH of the solution can be altered to either promote or slow-down the proton attack. This permits a flexible reaction time and ‘spending’ of the solution. The desire is to have a relatively slow reaction time to allow good coverage of the wash solution across the area of the wellbore to be treated. For long, open-hole completion, this can be an important factor which traditional acids are not good for. The fast reaction time means that the carbonate filter cake which the acid contacts first is dissolved almost immediately, leading to loss of the acid in this relatively high permeability zone thereby leaving the rest of the section untouched by the wash fluid.

Typical Properties:

Notes:

Make-up water used to mix OLKLIN^®-MCC-1 should meet the following quality:

total chloride less than 1500 ppm (mg/L)

total hardness less than 150 ppm as calcium

total chlorine less than 50 ppm

water pH between 8.5-9.5

Reduce total hardness of make-up water by adding soda ash

(sodium carbonate) at 0.6 – 1.2 kg / m³) of make-up water.

Packaging OLKLIN-MCC-1 is packaged in 220 kg hdpe barrel

Availability OLKLIN-MCC-1 is available within 48 working hours