Geological Drilling & Drilling Fluid Terminology

 

 Part 1 General Geological Drilling Terms

 

Drilling rig

 

 1. Drilling Rig & Equipment

1. Drilling rig

Complete integrated machinery set for breaking rock, running drill strings, circulating drilling fluid, pulling drill tools and conducting geological exploration drilling.

2. Core drilling rig

Specialized exploration rig designed to retrieve intact solid core samples from underground formations for mineral, engineering and geological survey analysis.

3. Exploration drill rig

Multi-functional rig applied in mineral prospecting, hydrogeological investigation and geotechnical reconnaissance, supporting coring and non-coring drilling modes.

4. Rotary drilling rig

Dominant drilling equipment that rotates drill pipes and bits to crush rock formations, compatible with soft soil, mudstone and hard granite strata.

5. Drill mast / Drill tower

Vertical load-bearing support structure for hoisting system, drill string and casing, providing vertical space for tripping operations.

6. Drill pipe

Hollow tubular component forming the drill string, transmitting rotational torque and carrying drilling fluid circulation down to the bit.

7. Drill collar

Thick-walled heavy tubular assembly installed above drill bit to provide sufficient weight on bit for rock breaking.

8. Core barrel

Hollow inner and outer tube assembly for capturing and storing rock core during coring runs.

9. Double tube core barrel

Coring tool with separated inner and outer tubes to reduce core erosion caused by circulating mud in fractured or swelling formations.

10. Triple tube core barrel

Three-layer coring device for extremely broken, loose and water-sensitive strata to maximize core recovery rate.

11. Drill bit

Bottom-hole cutting tool that contacts and breaks rock strata; categorized into diamond bit and carbide bit.

12. Diamond bit

Hard rock cutting bit embedded with synthetic diamond particles for high penetration rate in compact hard bedrock.

13. Carbide bit

Bit fitted with tungsten carbide inserts for soft-medium hard formations such as sandstone and mudstone.

14. Casing

Steel pipe lowered into borehole to prevent hole collapse, isolate water-bearing layers and maintain borehole integrity.

15. Surface casing

The first section of casing set at ground surface to seal loose overburden and shallow unconsolidated soil.

16. Swivel

Top rotating component connecting drill string and mud pipeline, allowing mud to flow into hollow drill pipes while rotating.

17. Rotary head

Power unit delivering rotational torque to the entire drill string on top of the mast.

18. Hoist

Lifting winch system for tripping drill pipes, core barrels and casing into or out of borehole.

19. Mud pump

High-pressure pump delivering drilling fluid from mud tanks downhole for hole cleaning and wellbore stabilization.

20. Triplex mud pump

Three-cylinder reciprocating mud pump with stable flow rate, widely used in geological core drilling projects.

21. Mud tank

Container for storing, mixing and conditioning drilling fluid, equipped with agitators and circulation pipelines.

22. Shale shaker

Primary solids control equipment with vibrating screens to separate large rock cuttings from returning mud.

23. Desander

Hydrocyclone device removing coarse sand particles suspended in drilling fluid after shale shaker treatment.

24. Desilter

Smaller hydrocyclone unit separating fine silt particles that cannot be removed by desanders.

25. Centrifuge

High-speed rotating separator extracting ultra-fine low-gravity solids from mud for low-solid drilling fluid maintenance.

26. Degasser

Processing equipment eliminating entrained air and formation gas bubbles inside circulating mud to stabilize mud density.

27. Mixing hopper

Venturi feeding device for rapid mixing of powdered additives and bentonite into base mud.

28. Agitator

Stirring impeller installed in mud tanks to prevent solid weighting agents and clays from sedimentation.

 

2. Borehole & Drilling Operation

1. Borehole / Wellbore

Underground cylindrical cavity formed by continuous rock breaking during drilling.

2. Borehole diameter

Inner width measurement of the drilled hole, determined by bit outer diameter and casing specification.

3. Drilling depth

Vertical or inclined distance from ground surface to the current bottom of the borehole.

4. Core drilling

Drilling technology focusing on retrieving intact rock core samples for geological stratigraphic identification.

5. Rotary drilling

Rock breaking method relying on rotational friction and cutting force of drill bits.

6. Percussive drilling

Impact-based drilling technique using repeated hammer strikes to fragment hard rock formations.

7. Wireline coring

Efficient coring process using inner tube retrieval cable without pulling out the whole drill string, saving tripping time.

8. Dry drilling

Drilling operation without circulating liquid mud, adopted in shallow dry soil layers with no groundwater.

9. Underbalanced drilling

Drilling mode where mud column pressure is lower than formation pore pressure to improve penetration rate.

10. Core recovery

Percentage of intact rock core retrieved relative to total drilled core length, a key coring quality index.

11. Core sample

Stratified rock specimen obtained from core barrels for lab geological testing and mineral analysis.

12. Borehole deviation

Deviation of actual borehole trajectory from designed vertical or inclined drilling path.

13. Vertical hole

Straight borehole with minimal horizontal deviation, used for most general geological exploration.

14. Inclined hole

Directional borehole drilled at a designed tilt angle for dipping ore bodies and slope engineering surveys.

15. Hole collapse

Instability failure of borehole wall where loose rock and clay slough into the wellbore.

16. Lost circulation

Uncontrolled leakage of drilling fluid into fractured, porous or cavernous formations.

17. Borehole wall stabilization

Comprehensive mud treatment and casing operation to maintain intact wellbore wall during drilling.

18. Tripping

Complete process of pulling drill string out of hole or running drill string back down to bottom hole.

19. Running casing

Operation of lowering steel casing pipes into borehole to seal unstable shallow formations.

20. Pull out of hole

Tripping action to extract the entire drill string assembly from the borehole.

21. Rate of Penetration (ROP)

Measurement of drilling footage per unit time, reflecting drilling efficiency of bits and mud system.

22. Weight on Bit (WOB)

Vertical downward load applied on drill bit by drill collars to enhance rock cutting efficiency.

23. Rotary speed

Rotational revolutions per minute of the drill string controlled by rotary head power unit.

24. Circulation

Closed loop flow of drilling fluid: pumped down drill string, flowing through bit, returning upward through annulus to mud tanks.

25. Circulation loss

General term for partial or full mud leakage into permeable underground formations.

 

Core sample

 

3. Geological Formations

1. Formation

Continuous stratigraphic rock layer with consistent lithology and geological age.

2. Bedrock

Solid intact rock underneath loose overburden soil and gravel layers.

3. Overburden

Unconsolidated surface soil, sand and gravel covering bedrock strata.

4. Clay stratum

Water-sensitive soft layer rich in clay minerals prone to hydration swelling.

5. Sand layer

Loose unconsolidated layer composed of fine to medium quartz sand particles.

6. Gravel layer

Coarse unconsolidated stratum with large rock fragments and poor particle cementation.

7. Fractured formation

Rock mass developed with dense natural cracks, highly prone to lost circulation and hole collapse.

8. Fractured rock

Hard rock cut through by structural fissures and tectonic fractures.

9. Aquifer

Permeable stratum storing and transmitting underground groundwater.

10. Water bearing formation

General term for any stratigraphic layer containing movable pore water.

11. Loose formation

Uncemented soil and gravel layers with poor self-supporting ability.

12. Hard rock

Compact, high compressive strength rock such as granite, basalt and quartzite.

13. Soft rock

Low-strength easily hydrated rock including mudstone, shale and argillite.

14. Fault zone

Tectonic fracture zone with crushed broken rock, the highest risk formation for borehole instability.

15. Mudstone

Fine-grained sedimentary rock rich in clay minerals with severe hydration swelling tendency.

16. Sandstone

Cemented granular rock with high permeability, easy to cause mud circulation loss.

17. Limestone

Carbonate rock containing natural solution cavities and fractures.

18. Granite

Hard igneous bedrock requiring diamond bits for efficient coring.

19. Swelling clay

High-montmorillonite clay that absorbs water and expands rapidly to shrink borehole diameter.

20. Water sensitive formation

Strata containing clay minerals that deteriorate instantly when contacted with untreated water-based mud.

 

Mudstone

 

Part 2 Drilling Fluid (Drilling Mud) Complete Terminology

 

1. Drilling Fluid Classification

1. Water-based drilling fluid (WBM)

Base fluid formulated with fresh water or salt water as continuous phase, low cost and widely used in geological core drilling.

2. Fresh water mud

Mud mixed with surface fresh water, suitable for non-saline, low-hardness geological formations.

3. Salt water mud

Water-based mud mixed with sodium chloride salt to suppress hydration of swelling clay strata.

4. Saturated salt mud

Mud with saturated sodium chloride concentration for severe water-sensitive montmorillonite formations.

5. Polymer water-based mud

Low-solid mud blended with high-molecular polymer additives for wellbore stabilization and filtration control.

6. Inhibitive water-based mud

Special WBM with clay inhibitor additives to prevent clay swelling and borehole sloughing.

7. Oil-based drilling fluid (OBM)

Mud with oil as continuous phase, excellent lubricity and strong anti-hydration performance for complex deep formations.

8. Synthetic-based mud (SBM)

Environment-friendly synthetic hydrocarbon base fluid replacing traditional crude oil mud, low toxicity for eco-sensitive drilling sites.

9. Invert emulsion mud

Emulsified OBM/SBM where water droplets disperse in continuous oil phase, high temperature resistant.

10. Solid-free mud

Drilling fluid without inert bentonite solids, applied in shallow exploration drilling to reduce solid control burden.

11. Low-solid mud

WBM with controlled low total solid content to maintain low viscosity and high penetration rate.

12. Foam drilling fluid

Aerated lightweight mud with stable foam system for low-pressure depleted formations to avoid circulation loss.

13. Aerated mud

Water mud mixed with compressed air to reduce overall mud density for underbalanced drilling.

14. Clay mud

Simple base mud mixed only with bentonite clay, used for stable shallow hard rock drilling.

15. Biodegradable drilling fluid

Environmentally degradable mud additives for drilling projects near farmland, rivers and protected ecological zones.

 

2. Mud Performance Test Parameters

Density Indicators

1. Mud density / Fluid density

Mass of drilling fluid per unit volume, controlled to balance formation pore pressure and prevent borehole collapse.

2. Mud balance

Portable measuring instrument to test field mud density on site.

3. Specific Gravity (SG)

Ratio of mud density to pure water density, standard comparative density unit for drilling fluid.

4. Low density mud

Light-weight mud with density below 1.05 g/cm³ for shallow low-pressure formations.

5. High density mud

Weighted mud mixed with weighting agents to generate high hydrostatic pressure for high-pressure strata.

6. Weighting agent

High-density solid powder added to increase mud density, such as barite and calcium carbonate.

 

Rheological Properties

1. Viscosity

Internal flow resistance of drilling fluid, critical for suspending rock cuttings and carrying debris out of borehole.

2. Funnel viscosity

Field quick-test viscosity measured by Marsh funnel, simple indicator for daily mud conditioning.

3. Apparent Viscosity (AV)

Total fluid viscosity measured under standard rotational shear rate, combining plastic viscosity and yield point.

4. Plastic Viscosity (PV)

Viscosity contribution from solid particle friction inside mud, reflecting content of inert suspended solids.

5. Yield Point (YP)

Initial shear stress required to make mud flow, representing mud’s capacity to suspend drill cuttings statically.

6. YP/PV ratio

Ratio of yield point to plastic viscosity, key index evaluating shear thinning performance of polymer mud.

7. Gel strength

Static shear stress formed when mud stays static, determining cutting suspension ability during pump shutdown.

8. Initial gel strength

Gel strength measured after mud stands static for 10 seconds.

9. 10-min gel strength

Gel strength measured after 10 minutes static standing, also called final gel strength.

10. Shear force

Mechanical cutting force applied to mud by drill string rotation and mud pump circulation.

11. Shear thinning

Desirable mud property where viscosity drops under high shear flow and recovers under static conditions.

12. Rheometer

Lab precision instrument measuring full rheological curve and all mud rheology parameters.

13. Flow curve

Graph plotting mud shear stress against shear rate to analyze fluid flow behavior.

 

Filtration & Wall Building Performance

1. Fluid loss / Filtration loss

Volume of liquid filtrate leaking from mud into porous formation under pressure.

2. API fluid loss

Standard low-temperature low-pressure filtration test specified by American Petroleum Institute.

3. High Temperature High Pressure fluid loss (HTHP)

Filtration loss tested under simulated deep borehole high temperature and pressure conditions.

4. Filter cake

Dense solid film deposited on borehole wall when mud filtrate penetrates formation pores.

5. Thin filter cake

Dense, low-thickness filter cake formed by qualified mud additives to reduce filtration loss.

6. Filter cake thickness

Measured thickness of solid cake after standard filtration test, excessive thickness causes high pipe friction.

7. Wall building property

Mud’s ability to form compact impermeable filter cake on borehole wall to block filtrate invasion.

8. Filter paper

Standard porous paper used inside filter press for fluid loss measurement.

9. Filter press

Lab testing device to quantify API and HTHP filtration loss values.

 

Solid, Sand & Oil Content

1. Solid phase

All suspended solid particles contained in drilling fluid, divided into low-gravity and high-gravity solids.

2. Low solid content

Target control standard for polymer mud to minimize flow resistance and bit balling risk.

3. High solid content

Excessive accumulated rock cuttings and clay solids leading to high viscosity and slow penetration rate.

4. Sand content

Volume percentage of coarse inert sand particles in mud, high sand content accelerates pump and bit abrasion.

5. Sand content tester

Glass graduated measuring cylinder for field sand content quantification.

6. Oil content

Volume percentage of base oil or lubricant additive inside oil-based mud.

7. Retort analysis

Distillation lab test separating mud into water, oil and solid phases for content calculation.

8. Suspended solids

Solid particles floating evenly in circulating mud without sedimentation.

9. Cuttings solids

Rock debris generated by bit rock breaking, the main source of low-gravity solids.

10. Low Gravity Solid (LGS)

Light solid particles including bentonite, rock cuttings and fine silt.

11. High Gravity Solid (HGS)

Heavy weighting agent solids such as barite powder added to raise mud density.

 

Chemical & Ion Properties

1. pH value

Acidity-alkalinity index of mud, controlled between 8.5–10.5 for stable polymer additive performance.

2. Alkalinity

Total concentration of alkaline ions in mud resisting acid formation contamination.

3. Total alkalinity

Overall alkaline content measured via titration to monitor mud chemical stability.

4. Calcium ion

Ca²⁺ cations invading mud from gypsum and limestone formations, damaging polymer mud performance.

5. Magnesium ion

Mg²⁺ ions from magnesium-rich strata causing flocculation of bentonite clay.

6. Chloride ion

Cl⁻ salt ions from saline aquifers, used to calculate formation water salinity.

7. Chloride content

Measured chloride concentration to judge salt contamination degree of drilling fluid.

8. Salinity

Total dissolved salt concentration in mud aqueous phase.

9. Total Dissolved Solids (TDS)

Mass of all dissolved inorganic salts in mud filtrate per liter.

10. Hardness

Combined calcium and magnesium ion concentration causing mud chemical contamination.

11. Corrosivity

Mud’s ability to corrode steel drill pipes and casing under downhole temperature.

12. Corrosion inhibitor

Additive coating metal surfaces to reduce electrochemical corrosion from saline mud.

 

Auxiliary Mud Performance

1. Lubricity

Mud’s friction reduction capacity between drill string and borehole wall.

2. Lubricity coefficient

Quantitative index measuring friction resistance of mud for metal-rock contact.

3. Anti-swelling capacity

Inhibitor mud performance restricting montmorillonite clay water absorption and expansion.

4. Temperature resistance

Maximum temperature mud additives can withstand without chemical decomposition.

5. Thermal stability

Retention of original mud properties after long exposure to high downhole temperature.

6. Anti-collapse performance

Comprehensive mud capacity to stabilize fractured, swelling and broken borehole walls.

7. Anti-leakage property

Mud system’s ability to plug porous and fractured formations and reduce lost circulation.

8. Flocculation

Undesirable particle aggregation caused by salt/calcium contamination leading to high mud viscosity.

9. Dispersion

Uniform distribution of clay and polymer particles in mud without agglomeration.

10. Compatibility

Stable coexistence of multiple mud additives without chemical reaction or performance failure.

11. Foaming tendency

Tendency of mud to generate stable bubbles after gas invasion or over-dosing foaming additives.

12. Defoaming performance

Additive ability to eliminate foam and recover accurate mud density readings.

 

3. Drilling Fluid Additives & Chemicals

Base Mud Raw Materials

1. Bentonite

Natural clay mineral rich in montmorillonite, the basic viscosifier for water-based mud.

2. Sodium bentonite

High-swelling sodium-type bentonite for fresh water base mud preparation.

3. Calcium bentonite

Low-swelling calcium-based clay requiring soda ash activation before mud mixing.

4. Attapulgite

Needle-shaped clay mineral maintaining viscosity under high salt contamination conditions.

5. Sepiolite

Salt-resistant fibrous clay for saturated salt drilling fluid systems.

6. Clay

General term for natural soil clay used in simple shallow drilling mud.

 

Weighting Agents

1. Barite / Barium sulfate

Primary weighting mineral powder with high specific gravity, non-toxic and widely used worldwide.

2. Hematite

Iron oxide weighting agent for ultra-high density mud systems.

3. Calcium carbonate

Light weighting and bridging agent for low-density mud and temporary plugging.

4. Manganese tetraoxide

High-density weighting material applied in special high-pressure drilling operations.

 

Filtration Control Agents

1. Sodium Carboxymethyl Cellulose (CMC)

Water-soluble cellulose polymer reducing API and HTHP fluid loss in fresh water mud.

2. High-viscosity CMC

Grade CMC mainly used to increase mud viscosity and suspension capacity.

3. Low-viscosity CMC

Low molecular weight CMC focusing on filtration control without excessive viscosity rise.

4. Polyanionic Cellulose (PAC)

Salt-resistant cellulose derivative stable in saline and calcium-contaminated mud systems.

5. PAC-LV

Low-viscosity polyanionic cellulose for filtration control in weighted high-density mud.

6. PAC-HV

High-viscosity polyanionic cellulose for viscosity building in low-solid polymer mud.

7. Modified starch

Biodegradable natural polymer controlling fluid loss in eco-friendly shallow drilling mud.

8. Sulfonated phenolic resin (SMP)

High-temperature resistant synthetic resin controlling HTHP filtration loss in deep hot formations.

9. Sulfonated lignite (SMC)

Low-cost natural coal derivative combining filtration control and viscosity reduction functions.

10. Sulfonated asphalt

Modified asphalt forming flexible filter cake to seal micro-fractures and prevent clay hydration.

 

HV-CMC

PAC-HV

 

Clay Inhibitors & Anti-Collapse Additives

1. Potassium chloride (KCl)

Common inorganic inhibitor releasing potassium ions to enter clay crystal layers and stop water absorption.

2. Ammonium chloride

Low-cost inorganic clay inhibitor for mild swelling clay formations.

3. Potassium polyacrylate (K-PAM)

Anionic polymer encapsulating clay particles to isolate formation water.

4. Polyamine inhibitor

Cationic polyamine additive with strong long-term anti-swelling performance for complex water-sensitive strata.

5. Quaternary ammonium salt

Cationic surfactant inhibitor adsorbing tightly on clay mineral surfaces.

6. Glycol / Polyglycol

Water-soluble polyether forming protective film on borehole wall to suppress shale swelling.

7. Silicate

Inorganic silicate agent forming impermeable silicate film on fractured rock surfaces.

8. Cationic polymer

High-molecular cationic polymer encapsulating cuttings and clay to prevent hydration dispersion.

 

KPAM

Viscosifiers & Gel Strength Enhancers

1. Xanthan gum

Biopolymer with outstanding shear thinning and salt resistance for low-solid mud.

2. Guar gum

Natural plant gum rapidly increasing mud viscosity and cutting suspension capacity.

3. Polyacrylamide (PAM)

High-molecular polymer for viscosity building, clay encapsulation and solid flocculation.

4. Amphoteric polymer

Dual-charge polymer compatible with both anionic and cationic mud additives.

5. Hydroxyethyl Cellulose (HEC)

Non-ionic cellulose viscosifier stable in high-salinity brine mud.

 

Thinners & Dispersants

1. Ferrochrome lignosulfonate (FCLS)

Traditional lignin-based dispersant breaking clay flocculation to reduce mud viscosity.

2. Calcium lignosulfonate

Calcium salt lignin thinner suitable for medium-temperature fresh water mud systems.

3. Sodium lignosulfonate

Sodium-type lignosulfonate dispersant with better salt contamination tolerance.

4. Organic phosphate

High-temperature anti-flocculation thinner for deep well high-density mud.

5. Sulfonated styrene copolymer

Synthetic polymer dispersant maintaining stable rheology under HTHP conditions.

 

SJN

Lubricants

1. Mineral oil lubricant

Refined petroleum oil reducing friction between drill string and borehole wall.

2. Vegetable oil ester

Biodegradable ester lubricant for environmentally restricted drilling projects.

3. Graphite

Solid layered lubricant filling micro-fractures on filter cake to lower friction coefficient.

4. Glass bead

Micro-spherical solid lubricant reducing metal-rock contact friction.

5. Extreme pressure lubricant

Special lubricant forming anti-wear film under high downhole contact pressure.

 

Glass bead

Defoamers

1. Silicone defoamer

High-efficiency organosilicon additive eliminating stable foam in salt water polymer mud.

2. Polyether defoamer

Water-soluble polyether antifoam agent suitable for low-temperature shallow drilling mud.

 

Lost Circulation Materials (LCM)

1. Bridging agent

Particle-sized solid material forming physical bridge across formation fracture openings.

2. Calcium carbonate fine powder

Fine particle bridging agent for micro-fracture temporary plugging.

3. Mica

Flaky mineral sealing thin formation cracks to reduce filtrate and mud leakage.

4. Walnut shell powder

Elastic granular LCM for medium-width fracture plugging.

5. Cotton fiber

Soft fibrous material filling irregular fracture voids to form flexible plugging layer.

6. Sawdust

Low-cost plant fiber lost circulation material for shallow low-pressure fractured formations.

7. Plugging polymer

Cross-linkable polymer gel forming elastic sealing layer inside large fractures.

8. Rigid plugging agent

Hard mineral powder forming rigid physical bridge for wide open fractures.

9. Flexible plugging agent

Elastic granular material adapting to variable fracture opening sizes under formation pressure.

 

Biocide, Corrosion Inhibitor & pH Adjusters

1. Biocide / Bactericide

Microbe-killing additive preventing polymer degradation caused by anaerobic bacteria in mud tanks.

2. Corrosion inhibitor

Film-forming chemical reducing electrochemical rust of steel drill tools and casing.

3. Caustic soda / Sodium hydroxide (NaOH)

Strong alkali to raise mud pH value and activate bentonite clay particles.

4. Soda ash / Sodium carbonate (Na₂CO₃)

Softening agent removing calcium contamination and activating calcium bentonite.

5. Lime / Calcium hydroxide

Alkaline additive adjusting mud alkalinity and treating gypsum contaminated formations.

 

4. Solids Control System

1. Mud circulation system

Complete closed-loop pipeline and tank system transporting mud from pump to borehole and back to processing tanks.

2. Mud pit

General term for all mud storage, mixing and settling tanks at drilling site.

3. Reserve pit

Standby tank storing pre-conditioned spare mud for emergency hole stabilization.

4. Settling pit

Static sedimentation tank allowing coarse rock cuttings to sink to tank bottom naturally.

5. Mud cleaner

Combined shale shaker and hydrocyclone integrated unit for secondary solids removal.

6. Mud gun

High-pressure jet nozzle stirring tank bottom to prevent solid weighting agent sedimentation.

7. Mixing tank

Special tank equipped with mixing hopper for preparing fresh base mud and adding chemical additives.

8. Waste cuttings

Solid rock debris separated out by solids control equipment requiring environmental treatment before discharge.

9. Mud waste treatment

Process of treating waste drilling mud and cuttings to meet local environmental discharge standards.

 

5. Downhole Mud Problems & Malfunctions

1. Hole collapse / Borehole sloughing

Wellbore wall rock falls into borehole due to insufficient mud density or poor clay inhibition.

2. Clay swelling

Montmorillonite clay absorbs mud filtrate, expands and narrows borehole diameter.

3. Bit balling

Sticky clay accumulates and wraps drill bit cutting surface, blocking rock breaking and circulation flow paths.

4. Pipe sticking

Drill string immobilized inside borehole caused by filter cake adhesion or cuttings accumulation.

5. Differential pressure sticking

Pipe stuck by pressure difference between mud column and formation across thick filter cake.

6. Severe fluid loss

Excessive filtrate invading formation leading to thick filter cake and borehole instability.

7. Excessive viscosity

Over-high mud flow resistance caused by over-dosing polymers or heavy solid contamination.

8. Mud foaming

Large volume of bubbles trapped in mud after gas cut, reducing effective mud density.

9. Salt contamination

Formation brine invades mud, causing bentonite flocculation and rheology deterioration.

10. Calcium contamination

Calcium ions from gypsum/limestone destroy polymer molecular structure and raise mud viscosity sharply.

11. Gypsum contamination

Calcium sulfate formation invasion generating massive flocculation of water-based mud.

12. Gas cut mud

Formation gas mixes into circulating mud, lowering hydrostatic pressure and risking borehole collapse.

13. Solids overload

Uncontrolled accumulation of rock cuttings solids overwhelming solids control equipment capacity.

14. Poor filter cake

Porous, thick and loose filter cake caused by insufficient filtration control additives.

15. High friction resistance

Elevated drag force between drill string and borehole wall from low mud lubricity.

 

6. On-Site Mud Operation Terms

1. Mud mixing / Mud preparation

Complete procedure of mixing bentonite, water and chemical additives to prepare qualified base mud.

2. Premix

Pre-dissolve high-concentration polymer additive solution before adding into main mud tank.

3. Mud dilution

Add fresh water to reduce mud density and cut excessive solid concentration.

4. Mud conditioning

Adjust mud rheology, filtration and inhibition performance by targeted additive dosing.

5. Mud treatment

Comprehensive chemical remediation of contaminated mud to recover original performance.

6. Circulating mud

Maintain continuous pump circulation to suspend cuttings and evenly distribute additives.

7. Mud sampling

Collect representative mud samples from return flow for lab performance testing.

8. Mud testing

Carry out density, viscosity, fluid loss and chemical index measurement on site or laboratory.

9. Maintain mud property

Continuous daily additive adjustment to stabilize mud performance during long drilling runs.

10. Discharge waste mud

Treat and discharge spent drilling mud after reaching service life.

11. Mud recycling

Process returned mud via solids control equipment for repeated circulation use.

 

Part 3 Common Industry Abbreviations

 

1. WBM – Water-Based Mud: Water-continuous phase drilling fluid system
2. OBM – Oil-Based Mud: Oil-continuous phase invert emulsion drilling mud
3. SBM – Synthetic-Based Mud: Eco-friendly synthetic hydrocarbon base drilling fluid
4. PV – Plastic Viscosity: Rheology parameter reflecting inert solid friction
5. YP – Yield Point: Index measuring static cutting suspension capacity
6. AV – Apparent Viscosity: Total measured viscosity under standard shear rate
7. HTHP – High Temperature High Pressure: Simulated deep downhole test condition
8. API – American Petroleum Institute: Global standard organization for mud test methods
9. LCM – Lost Circulation Material: Additive for plugging fractured leak zones
10. ROP – Rate of Penetration: Drilling footage per hour evaluating drilling efficiency
11. WOB – Weight on Bit: Vertical load applied onto drill bit for rock breaking
12. CMC – Carboxymethyl Cellulose: Common water-based mud filtration control polymer
13. PAC – Polyanionic Cellulose: Salt-resistant cellulose filtration reducer
14. PAM – Polyacrylamide: Multi-functional polymer for inhibition and viscosity building
15. TDS – Total Dissolved Solids: Total dissolved salt concentration in mud filtrate
16. SG – Specific Gravity: Relative density of drilling fluid compared to pure water
17. LGS – Low Gravity Solid: Light solid particles from bentonite and rock cuttings
18. HGS – High Gravity Solid: Heavy weighting agent solids such as barite powder

 

Contact Us

Company Name: SanheRunjing Technology Co., Ltd.

Core Business: R&D & production of drilling fluid additives, drilling fluid testing technical guidance, drilling construction technical service

Location: Room 305, 3rd Floor, Building 1, Yard 7, Guangyang New Road, Fangshan District, Beijing, China

 

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