Drilling Fluids & Process Liquids

«BURINTEKH», Ltd renders drilling fluids service since 2005. Currently by means of drilling mud department specialists there are drilled more than 350 wells (including >100 lateral wells and >60 with horizontal ending) on more than 30 fields of Western and Eastern Siberia, Tomsk and Orenburg regions in different mining and geological conditions, categories of difficulty and designs. Our partners and customers are the major oil and gas production enterprises and drilling companies.

Each object is supplied with modern mobile accommodation and field laboratory inside it which is in accordance with all requirements and regulations. Qualified engineers provide measuring of parameters and properties of fluids according the API standards using the «OFITE» equipment.

Engineers use specially developed software:
«Hydraulic BIT» - program purposed for calculation and designing hydraulic parameters of drilling.
«FD-Protection» - program for selection fractional composition of colmatant where is used new methodology of selection fractional composition of colmatant by Vickers criterion including as Abrams theory so Kauffers (perfect-package theory) implicative more precise selection of fractions for big, medium, small and intermediate pores if formation.

24-hour project managing is provided though regional representatives in Nefteyugansk, Nijnevartovsk, Noyabrsk, Gubkinsky, Novy Yrengoy, Orenburg, Buzuluk. Central laboratory in Ufa and regional laboratory in Nefteyugansk render technical support to service objects.

«BURINTEKH», Ltd drilling muds service offers its solutions for drilling and completion of deep and ultra deep wells sidetracks in difficult mining and geological conditions in form of own drilling mud systems and process liquids:

  • drilling fluid SKIF
  • drilling fluid SKIF+
  • biopolymer inhibiting carbonate fluid POLYCARB BIO
  • oil based muds EMULCARB
  • drilling mud for drilling fractured reservoirs SULFOBIT
  • gel-emulsive drilling mud with density up to 1.60 g/cm3 without barite MULTIBUR
  • aerated drilling mud
  • water based mud for drilling in high temperature conditions (up to 240°C)
  • process liquids without solids with density 1.35-2.30 g/cm3
  • process liquid for bottom-hole formation zone cleaning
  • backfill mixture for flushing fluids lost circulation control

Drilling fluid «SKIF»

«SKIF» is specialized flushing fluid with optimal performance properties for drilling depleted sandstones, water-sensitive rocks where chances of differential sticking are high when drilling holes with big deviation.

Application

Drilling well with big horizontal displacement, long intervals of unstable and water-sensitive formations, tailing-in.

Features

  • high quality of borehole cleaning
  • usage of biodegradable components
  • use of complex inhibiting
  • minimum effect on reservoir properties of producing formations

Advantages

  • high inhibiting ability
  • low filter value
  • easy mud parameters control
  • good lubricating features

Main parameters

Density, g/cm3

1.06…1.10

Relative viscosity, s

35…55

Filtration rate, ml/30 min

6…9

Plastic viscosity, cP

≥22

Yield point, lbs/100 ft2

15…30

Gel strength 10s/10min, lbs/100 ft2

4-12/6-20

8…9

, kg/m3

≥40

Solids content, %

≥8

Total hardness, mg/l

≥200

Chloride content l-, mg/l

1.0…30.0


«SKIF» and «SKIF+» systems provide qualitative well cleaning from drilled out rocks and stability of wellbore walls.

Non-linearity of rheological features is determined by the use of xanthum range as part of biopolymer. Thereat mud differs by its increased carrying ability in static condition and creates low resistances at increasing shearing rate.

Ability of systems to obtain features of pseudo plastic fluid provides good borehole cleaning and small values of plastic viscosity provide good mud cleaning from cuttings on the surface.

«SKIF» and «SKIF+» systems are successfully used on Western Siberian fields there are drilled more than 150 wells in different geological conditions.

Influence of muds to reduction of bottomhole formation zone permeability to oil

Mud type / Core sample

Lfiltration, mm

break-off, psi/atm

βresidual, %

«SKIF» / kabs = 17 mD

248

204/14

85.9

«SKIF+» / kabs = 15.8 mD

242

258/17.8

71.2

Note:
Lfiltration - depth of killing fluid filtrate invasion to core sample;
breake-off - pressure of initiation of oil stimulation treatment after mud effect;
βresidual - restoration of oil permeability after imitation secondary tailing-in in relation to layer permeability before mud effect.

Drilling fluid «SKIF+»

«SKIF+» is the complex encapsulating formiate system pueposed for drilling directiona; and fflat wells in conditions of unstable formations and swelling clay slates.

Application

Drilling wells in strongly swelling clay slates, tailing-in wells supposing development by means of hydraulic fracturing.

Features

  • synergism of performance organic inhibitor and acrylic copolymer
  • high thermal stability (up to 120°)
  • provision of wellbore stability
  • high encapsulating and flocculating features
  • minimum percentage of colloid solid phase in solution
  • high electrical resistivity (~1 Om⋅M)

Advantages

  • high inhibiting ability
  • low filter value
  • high lubricating features
  • high drilling rate
  • absence of balling

Main parameters

Density, g/cm3

1.06…1.10

Relative viscosity, s

35…45

Filtration rate, ml/30 min

6…9

Plastic viscosity, cP

10…20

Yield point, lbs/100 ft2

5…25

Gel strength 10s/10min, lbs/100 ft2

3-10/5-20

8…9

, kg/3

≥40

Solids content, %

≥8

Total hardness, mg/l

≥200

Chloride content l-, mg/l

≥1500


«SKIF» and «SKIF+» systems provide qualitative well cleaning from drilled out rocks and stability of wellbore walls.

Non-linearity of rheological features is determined by the use of xanthum range as part of biopolymer. Thereat mud differs by its increased carrying ability in static condition and creates low resistances at increasing shearing rate.

Ability of systems to obtain features of pseudo plastic fluid provides good borehole cleaning and small values of plastic viscosity provide good mud cleaning from cuttings on the surface.

«SKIF» and «SKIF+» systems are successfully used on Western Siberian fields there are drilled more than 150 wells in different geological conditions.

Influence of muds to reduction of bottomhole formation zone permeability to oil

Mud type / Core sample

Lfiltration, mm

break-off, psi/atm

βresidual, %

«SKIF» / kabs = 17 mD

248

204/14

85.9

«SKIF+» / kabs = 15.8 mD

242

258/17.8

71.2

Note:
Lfiltration - depth of killing fluid filtrate invasion to core sample;
breake-off - pressure of initiation of oil stimulation treatment after mud effect;
βresidual - restoration of oil permeability after imitation secondary tailing-in in relation to layer permeability before mud effect.

Biopolymer inhibiting carbonate mud «POLYCARB BIO»

«POLYCARB BIO» - is clay-free flushing fluid for primary tailing-in and drilling horizontal sections.

Application

Tailing-in with medium and high permeability with the purpose of preserving its physical and chemical characteristics.

Features and advantages

  • ability of selection inhibitive additive
  • wide range adjustable rheological features
  • low filter value
  • usage as calcium carbonate colmatant of calculated fractional composition
  • convertible hydrophobic ability in relation to surface of layer pore channels
  • minimum reduction of bottomhole formation zone permeability
  • usage of environmentally safe reagents
  • 100% destruction at acidizing

Main parameters

Density, g/cm3

1.06…1.10

Relative viscosity, s

45…65

Filtration rate, ml/30 min

≥6

HPHT, ml/30 min

≥12

Plastic viscosity, cP

≥15

Yield point, lbs/100 ft2

15…35

Gel strength 10s/10min, lbs/100 ft2

5-10/8-20

8…9.5

, kg/m3

≥30

Solids content, %

≥6

Total hardness, mg/l

≥200


Influence of muds to reduction of bottomhole formation zone permeability to oil with different inhibitors

Mud type / Core sample

Lfiltration, mm

βresidual, %

«POLYCARB BIO» (4% KCl) / kabs = 41.15 mD

205

91.2

«POLYCARB BIO» (3% NaCO2H) / kabs = 41.18 mD

220

91.9

Note:
Lfiltration - depth of killing fluid filtrate invasion to core sample;
βresidual - restoration of oil permeability after imitation secondary tailing-in in relation to layer permeability before mud effect.

Oil based muds «EMULCARB»

«EMULCARB» - set of invert-emulsion drilling muds preserving in-place permeability.

System

Hydrocarbon bases

Attitude
hydrocarbon/water

«EMULCARB D»

Diesel

60/40

«EMULCARB M»

Mineral or hydraulic oil

70-80/30-20

«EMULCARB ECO»

Complex ester

80/20

«EMULCARB D» features

  • because of low water-oil ratio requires less expenditures connected with preparation
  • has low solidification temperate (less than -30°)
  • appropriate for drilling wells with low formation temperature
  • has low plastic viscosity and high yield point which provide good cutting transport and mud cleaning on the surface
  • provide effective drilling of directional wells by means of provision stability of wellbore and high lubricating features decreasing probability of drill pipe sticking
  • minimizes contamination of productive formation

«EMULCARB M» features

  • appropriate for drilling wells with high formation temperature
  • high flash-point and low solidification temperature lighten work with hydrocarbon
  • provides effective directional wells drilling
  • allows maximally preserve reservoir properties and in future lighten formation fluid retrieval

«EMULCARB ECO» features

  • drilling mud system based on compound ethers for drilling in conditions of exclusive environmental requirements
  • takes to account environmental constituent at elimination of waste
  • can be used at drilling well with big horizontal displacement and horizontal wells, and also at tailing-in
  • has better lubricating features than oil based muds and excludes the ability of sticking
  • especially effective for works in wells with complicated profile and horizontal ending

After drilling and system regeneration «EMULCARB» systems can be kept a long time or can be used as follows:

  • again on another wells
  • as fluid for conservation of well
  • as a packer fluid
  • for processing and preparation water based muds as an effective lubricating and anticorrosion additive
  • in well workover as a process fluid

Advantages of «EMULCARB» systems

  • well productivity preservation
  • reduction of torque and frictional force
  • increasing of ROP
  • provision of wellbore walls stability
  • ability of reutilization

Influence of emulsion to reduction of bottomhole formation zone permeability to oil

Mud type / Core sample

Lfiltration, mm

break-off,
psi/atm

βresidual, %

«EMULCARB D» (40°) / kabs = 24.7 mD

53

-/-

99.8

«EMULCARB M» (40°) / kabs = 65.1 mD

41

-/-

97

Emulsion (mixture of oil and diesel) (40°) /
kabs = 2500 mD

69

8/0.5

100

Note:
Lfiltration - depth of killing fluid filtrate invasion to core sample;
break-off - pressure of initiation of oil stimulation treatment after mud effect;
βresidual - restoration of oil permeability after imitation secondary tailing-in in relation to layer permeability before mud effect.

Drilling mud for drilling fractured reservoirs «SULFOBIT»

«SULFOBIT» is the drilling mud which includes special bituminous based reagent processed by means of special technology. This reagent is the clay slates swelling inhibitor, it prevents caving formation in the unstable formations (argillites) intervals, considerably improves lubricating features and decreases filter value.

Application

«SULFOBIT» fluid system is good for drilling fractured reservoirs and in swelling clay slates. Inhibiting and stabilizing effect can be reached by means of occlusion micro fissures in clays. Besides there is created on walls rubber-like oil-permeable cake preventing filtrate invasion but not deteriorating residual permeability during stimulation.

Addition of special component increases thermal stability of reagents and allows using solution at temperatures up to 160°C.

Features and advantages

  • prevents and considerably decreases caving formation of unstable formations (argillites) by means of inhibiting effect
  • has low cake friction coefficient
  • environmentally safe does not contain environmentally hazardous reagents
  • has high thermal stability
  • does not have an effect on logging results
  • nearly does not deteriorate primary production characteristics

Influence ofmud to reduction of bottomhole formation zone permeability to oil

Mud type / Core sample

Lfiltration, mm

breake-off, psi/atm

βresidual, %

«SULFOBIT» / kabs = 537 mD

389

19.2/1.3

93.9

«SULFOBIT» / kabs = 37.2 mD

201

128/8.8

97.6

Note:
Lfiltration - depth of killing fluid filtrate invasion to core sample;
breake-off - pressure of initiation of oil stimulation treatment after mud effect;
βresidual - restoration of oil permeability after imitation secondary tailing-in in relation to layer permeability before mud effect.

Gel-emulsion drilling mud «MULTIBUR»

«MULTIBUR» - gel-emulsion mud with increased inhibiting ability. By means of use ferrous salt there can be achieved density up to 1600 kg/m3. Because of absence of Mil-Bar the mud perfectly suits for tailing-in.

Application

For drilling different types of wells containing elongated intervals of active clays, unstable and avalanching clays and for tailing-in.

Features

  • the use of inhibiting by bivalent positive ions allows provision of filtrate activity lower than fluids activity which saturate clay rocks, this leads to dehydration of bottomhole formation zone and excludes clay minerals swelling
  • increased lubricating feature and wellbore walls stability is achieved by using 1st sort emulsion
  • provision of wellbore stability
  • high quality of wellbore cleaning is provided by using specially selected non-ionic polymers, structure-forming agents and filtrate agents
  • presence of specially selected fractional calcium carbonate leads to minimal filtrate invasion and solid phase and provide minimal effect to reservoir properties of productive formation

Advantages

  • high inhibiting ability
  • low filter value
  • good lubricating features
  • relatively low cost
  • preservation of productive formation permeability
  • wide range of densities without using Mil-Bar

Main parameters

Density, g/cm3

1.30…1.60

Relative viscosity, s

35…55

Filtration rate, ml/30 min

4…7

Plastic viscosity, cP

≥40

Yield point, lbs/100 ft2

20…50

Gel strength 10s/10min, lbs/100 ft2

15-20/9-10

8…9

, kg/m3

≥40

Solids content, %

≥15


Economy

By means of improved inhibiting, lubricating, capillary action on wellbore walls, «MULTIBUR» according its operational properties is equal to OBM, but exceeds it according to cost performance.

Influence of mud revelation of producing horizon

Developed mud leads to minimal contamination of productive layer flush with OBM.

Mud type

Core sample kabs, mD

βresidual, %

«MULTIBUR»

831

91.5

OBM

2500

98

Note:
βresidual - restoration of oil permeability after imitation secondary tailing-in in relation to layer permeability before mud effect.

There are conducted full-scale tests of mud, thereat the following was noted:

  • mud is solely stable (does not flake and foam)
  • perfectly inhibits clay (after drilling more than 800 m - MBT=7 kg/m3)
  • low content of solid phase does not contaminate layer
  • round trip operations carried-out without overpulls and landings
  • secondary use of system is possible
  • 35% increasing of average ROP
  • decreased expenses to mud because of reduction of prepared mud volume (33% in average)

Aerated drilling fluid

Aerated drilling fluid is foamed biopolymer mud with specific weight lower than water density.

Application

Drilling of formations with low formation pressure, qualitative tailing-in of depleted reservoirs with abnormally low formation pressure and with minimal negative action on reservoir properties at existing formation conditions.

Features and advantages

This mud can be prepared with use of:

  • fresh water
  • mineralized water
  • sea water
  • sodium chloride saturated solution
  • different formicates (individual salts and salt mixture)
  • solutions of different bromides
  • o with addition of colmatant CaCO3

Main parameters

Density, g/cm3

0.83…1.06

PV, cP (MPa⋅s)

21

AV, cP

44.5

YP, dPa

225.13

n

0.39

k, cP

3089.87

Gel 10 sec, dPa

110.17

Gel 10 min, dPa

124.54

Stability time, h

not less than 96

Lime and Gypsum muds

Lime and gypsum muds are inhibiting calcareous systems containing lime and gypsum as suppliers of kalium ions the action of which is based on conversion of natrium clay to calcium clay and prevention the transferring of drillied out formation to natrium, as a result of which hydration and swelling of clay-containing formations is reduced.

Application

Drilling in intervals of unstable clay-containing formations in conditions of carbon dioxide aggression and high temperatures.

Advantages

  • high inhibiting ability
  • thermal stability up to 160-200°
  • permanent content of Ca2+ in mud filtrate
  • low filter value
  • ability of receiving muds with high density (up to 2.2 g/cm3)
  • long-term stability to biological degradation

Main parameters

Density, g/cm3

1.10…2.20

Relative viscosity, s

40…60

Filtration rate, ml/30 min

4…5

Plastic viscosity, sP

20…50

Yield point, lbs/100 ft2

25…80

Gel strength 10s/10min, lbs/100 ft2

12-20/15-45

8…9

, kg/m3

≥40

Chloride content a2+, mg/l

700…3000

In consequence of low solubility of hydroxide and calcium sulfate lime and gypsum muds are self-adjusting systems. Content of calcium in it is almost permanent because lime and calcium sulphate are added to mud in plenty.

Lime and gypsum muds provide qualitative wellbore cleaning, stability of walls and have increased carrying ability in static condition.

Developed mud passed successful trials on Ozek-Suat field (Stavropol Territory) in conditions of high carbon dioxide aggression and high temperatures (up to 165°C) and water inflow.

Drilling fluid for high temperature conditions (up to 246°C)

Fluid is based on sulphonated synthetic acrylic copolymers.

Application

Purposed for drilling in conditions of high bottomhole temperatures (up to 246°C) and high mineralization, polymineral and sulphureous aggression.

Features

At recipe making up of thrmal and salt-resistant drilling mud are used four key reagents:

  1. Clay slates swelling inhibitor - in preference to inorganic salt.
  2. Acrylamide copolymers filtration and rheology regulators.
  3. Sulphonated asphalt filtration and rheology regulators.
  4. Bentonite - for creation filter cake and mud structure.
  5. Thermal resistant flocculant based on tannin viscosity regulator.

Main parameters

Density, g/cm3

2.09

PV, cP (MPa⋅s)

43

AV, cP

57

YP, dPa

134.12

n

0.68

k, cP

513.47

Gel 10 sec, dPa

23.95

Gel 10 min, dPa

33.53

Process liquids without solid phase with density up to 1.35-2.30 g/cm3

Prime objective of selection fluid for killing and well completion is minimization of contamination productive formation. In most regions with low formation pressures are used kalium,, natrium and calcium chloride brines which give the ability to prepare fluids with density from 1.02 to 1.36 g/cm3. In cases where required fluids with density higher than 1.36 g/cm3 wide range was found by calcium, natrium and zinc bromide salts, and recently also solutions based on sodium, kalium and cesium formats. Among standard operations which use clean brines are killing, fishing operations, perforation, flushing, drilling and washing up gravel-packed filter and also preparation of packer fluids. For performing necessary functions completion fluids must render backpressure to productive formation, transport solid particles, bring minimal contamination to productive formation, be stable on the surface and in bottomhole conditions, be environmentally benign or to be used at controllable effect to environment thereat the use of such fluids must be economically feasible.

Main features of completion fluids based on salts are density, content of mechanical admixtures and solidification temperature. Intended density in required for controlling formation pressure. Transparence or content of mechanical admixtures is defined with the purpose of controlling contamination of productive formation and punched holes. Solidification temperature defines ability of use brines in different weather conditions.

Inorganic salts and densities of received brines in use

Inorganic salts in use

Brine density, g/cm3

HCOONa

1.10÷1.34

CaCl2

1.08÷1.39

NaBr

1.20÷1.50

NaCl/NaBr

1.20÷1.50

2CO3

1.20÷1.55

HCOOK

1.30÷1.60

CaBr2

1.40÷1.81

CaCl2/ CaBr2

1,40÷1,81

CaBr2/ ZnBr2

1.68÷2.30

CaCl2/CaBr2/ZnBr2

1.70÷2.30

ZnBr2

2.30÷2.52

HCOOC2

1.73÷2.46

Process liquids for bottomhole formation zone cleaning

Process liquid for BFZ chemical cleaning represents synergic mixture of chemical and biological reagents selectively acting on components of mud used for tailing-in and on created filter cake.

Application

BFZ cleaning from filter cake deposited on wellbore walls, increasing productive formation permeability.

Features and advantages

  • environmental safety and low toxicity of reagents all used agents are biodegradable, have low biohazard class and are low-toxic
  • low corrosive activity - as distinct from traditional method of acid treatment this system is not corrosion active and does not require additional use of expensive corrosion inhibitors and special precautionary measures during transportation and storage
  • destruction solutions speed of response system components act more slowly and «softer» than acids, not liable to active chemical interactions with formation fluids or minerals building up reservoir which allows considerably decrease the risk of contamination of BFZ
  • abnormally high filtrate viscosity limiting its penetration to productive formation
  • low probability of contamination reservoir with reaction products components of process liquid for BFZ cleaning act selectively on filter cake components not entering in to cooperation wit reservoir and formation fluid transferring into fully water-soluble form the components of filter cake without creation mechanical admixtures able additionally contaminate BFZ
  • blend composition is selected individually depending on components of filter cake which is to be removed