GEOSYNTHESIS ENGINEERING

Development and service of drilling fluid

A complex agent, the polymer basis for clayless circulation fluid "BIOCAR®." ТУ У 24.1-34962841-005:2009

GENERAL CHARARACTERICTICS

Technical mixture of dry components that form viscous thixotropic suspension in aqueous medium.

BASIC PHYSICAL PROPERTIES

  • Water solubility: 95-98%;
  • Appearance of the ready-to-use reagent: viscous white fluid;
  • Reagent density: 1020-1030 kg/m3;
  • Level of pH: 8,5-9;
  • Reagent density: 1020-1030 kg/m3.

REAGENT MANUFACTURING TECHNOLOGY

  • Any mixing unit that can create intensive mixing and continuously maintain this process for 4 hours can be used for the reagent production.
  • The capacity for preparation is filled with clean fresh water.
  • When mixing, the dry reagent is added into the water at a rate of 60 kg per 1 m3 of fluid.
  • The mixture is mixed not less than 4 hours. Then the prepared reagent can be introduced into the drilling mud “BIOCAR®”, it can be used as a polymer basis for its production.

SPHERE AND METHOD OF APPLICATION

  • The “Biocar-compound” reagent is designed for production of the clayless drilling mud “BIOCAR®” and its provision with the specific rheological, structural, mechanical, and filtration properties.
  • After the “Biocar-compound” reagent was produced, other components of the “BIOCAR®” system are introduced into it: bactericide, salts, lubricants, pH regulator, colmatants. After having been mixed for 30-40 minutes, the mixture can be used as a drilling mud.
  • The “BIOCAR®” drilling mud salinity can vary depending on such geological conditions as formation temperature, activity of clay rocks, and required density. Correspondingly, there are two modifications of the system “BIOCAR®” and “BIOCAR-MT®”.
  • The latter is designed for the hardest drilling conditions and it is characterized by high density, thermal resistance, and increased inhibition properties.
  • The content of the “Biocar-compound” reagent in the clayless drilling mud is in the following ranges (in terms of dry substance):
    • 6-7% in the “BIOCAR®” system,
    • 7-9% in the “BIOCAR-MT®” system,
  • Properties of the “Biocar-compound” reagent as an inhibitor ensure effective suppression of hydration and clay rocks swelling in the systems “BIOCAR®” and “BIOCAR-MT®”. It is relevant for the operation under the most difficult geological conditions and at great depths.
  • Рhe “Biocar-compound” reagent has a side inhibitor and flocculating effect on the drilled clay rock, decreases the likelihood of packing of the BHA and drill bit elements, reduces the drilling mud life cycle, and improves operating conditions of the drilling-mud cleaning equipment.
  • If necessary, the “Biocar-compound” reagent can be used in conjunction with other types of polymeric reagents: CMC, biopolymers, starch, etc.

ADVANTAGES

  • The “Biocar-compound” reagent allows to obtain thixotropic drilling mud that ensures suspending of the weighting material and drilled cuttings without using any clay materials. Full exclusion of the clay component from the drilling mud allows to minimize irreversible contamination of the closed producing reservoirs.
  • The “Biocar-compound” reagent provides drilling mud with the 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 inhibiting property of the “Biocar-compound” reagent 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 polymer component of the “Biocar-compound” reagent is represented by the polysaccharide components that have the biodegradability property. This completely eliminates the problem of permeability reduction and, consequently, adsorption of the polymers on the porous reservoir surface.
  • “Biocar-compound” (with the colmatage property) in combination with carbonate and organic reagents provides for creation of impermeable filtration screen of the producing reservoir surface. This prevents formation of the wide zone of penetration and absorption of the drilling mud. Thus, there are conditions created for the safe operation in the permeable intervals, including in the ALFP zones.
  • “Biocar-compound” can be well combined with all types of the high-molecular polymeric reagents, which are traditionally used when drilling wells. Thermal resistance of the “BIOCAR®” system – 120-130oC, “BIOCAR-MT®” system – 140-150oC.
  • The peculiarity of the reagent consists in the low water extraction from the the drilling muds that were processed using it under formation temperatures (HPHT).
  • “Biocar-compound” ensures high lubricating properties of drilling muds. If additional lubricating additives are not used, friction coefficient of drilling muds on its basis has a level of 0,15-0,18.
  • The “Biocar-compound” reagent is a substance with the third danger level.
  • The “Biocar-compound” reagent is resistant to the influences of mono- and polyvalent salt action. The reagent components 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 system based on the “Biocar-compound” reagent. It allows to regulate the processes of biological decomposition 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.

LIMITATIONS

  • The “Biocar-compound” reagent should be produced on the basis of the clean fresh water.
  • In order to produce the reagent, mixing devices should be used.
  • The reagent preparation process lasts not less than 4 hours.
  • If the level of pH in the drilling mud is greater than 11, it causes destruction of biopolymers. The drilling mud on the basis of the “Biocar-compound” reagent is not recommended to be used when drilling out great cement bridges.
  • Polysaccharide basis of the “Biocar-compound” reagent is prone to biological destruction. It requires usage of bactericides in the reagent-based systems.
  • Thermal resistance of the “Biocar-compound” reagent, depending on the degree of the drilling mud salinity, is within the limits of 120-150oC.

PACKAGING AND STORAGE

  • The “Biocar-compound” reagent is supplied to the customer in dry form.
  • The reagent is packed into paper bags (30 kg).
  • The “Biocar-compound” reagent is recommended to be stored in a dry ventilated area.