Destined for drilling wells with great inclination angles, including horizontal, penetration in production zones and drilling in zones with abnormally low formation pressures.
A distinguishing feature of the are unique rheological properties that ensure effective cleaning of the bottom-hole, carrying-up of cuttings to the surface from the horizontal and directional wellbores, and absence of additional hydraulic resistance during well cleanout. The all components of the BIOCAR® system are only acid-soluble and biodegradable products. The permeability damage coefficient is at level of best world analogs.
ADVANTAGES
- The unique rheological properties of the BIOCAR® system ensure effective cleaning of the bottom-hole, carrying-up of cuttings to the surface from the horizontal and directional wellbores, and absence of additional hydraulic resistance during well cleanout.
- Full exclusion of the clay component from the drilling mud allows to minimize irreversible contamination of the closed producing reservoirs.
- The BIOCAR® system consist of polysaccharide components that have the biodegradability properties. This completely eliminates the problem of permeability reduction and, consequently, adsorption of the polymers on the porous reservoir surface.
- The toxicity of the BIOCAR® system and all its components does not exceed third danger level.
- The inhibiting property of the BIOCAR® system in conjunction with the similar action of salts increases the stability of the wellbore walls, reduces wellbore cavernosity, and prevents swelling and caving-in of rocks.
- The BIOCAR® system is resistant to the influences of mono- and polyvalent salt action. The components os system do not form any insoluble compounds when being in contact with the rocks that have formation fluids.
- The bactericides content can be controlled in the BIOCAR® system. It allows to regulate the processes of biodegradation of polysaccharides at its minimum concentration. Thus, on the one hand, it is possible to avoid destruction of the drilling mud system and associated excess reagents consumption, on the other hand – it allows to reduce the overall drilling mud toxicity and increase its environmental friendliness.
COMPOSITION AND PARAMETERS OF FLUSHING SYSTEM
Drilling mud composition:
- BIOCAR-Compound – 5-6% (A complex agent provides filtration and rheological properties of drilling mud);
- КСl - 2-3% (if necessary, the concentration of KCl can be increased to 10%);
- Alevron® - 0,5-1% (НРНТ controller of filtration and rheological properties);
- Calcium Carbonate Filler – 15-20% (Calcium carbonate concentration can be reduced to 5% depending on the desired density);
- K-200 - 1-1,5% (organic filling agent);
- Graphite - до 1% (before casing running);
- Weighting agents (baryte, hematite, chalk, ground limestone) - depending on the desired density;
- Bactericide, рН controller, lubricating additives, defoaming agent;
- Water - all the rest.
Parameters of drilling mud:
- Density - 1050-1450 kg/m3,
- Funnel viscosity - 45-95 s,
- Gel - 12 / 20-18/25 dPa,
- Filtration loss - 2-4 cm3/30 min,
- HPHT fluid loss at temperature 120-130 oC and pressure drop 5 МPа - 15-20 cm3/30min.
- PV - 16-28 mPa*s,
- YP - 130-190 dPa
- pH - 9.0-10.5.
