- First central momentum = μ1
- Gram = g
- m3/m3
- Machine learning
- Magnetic Defectoscopy
- Magnetic Exploration Survey
- Magnetic North direction
- Main Pay
- Management Accounting
- Marhoun (1980) oil correlations @model
- Marhoun (1988) bubble point pressure Pb @model
- Marhoun (1988) saturated oil formation volume factor Bo @model
- Marhoun (1988) saturated oil gas solubility Rs @model
- Market
- Market Cap (Business)
- Marketing (Business)
- Marketing & Sales Management
- Market survey
- Mass (physical property)
- Mass Conservation
- Mass Flowrate
- Mass Flux
- Mass Flux Vector
- Master Development Plan (MDP)
- Master Development Planning (MDP) @ procedure
- MatBal Flow @model
- Material
- Material Balance Analysis = MatBal
- Material Balance Pressure @model
- Material Balance Pressure Plot
- Material derivative
- Material property
- Mathematical Expression
- Mathematics
- Mature Petroleum Field
- Maximum Absolute Percentage Error = MAXAPE
- Maximum Absolute Relative Error = MAXARE
- Maximum Percentage Error = MAXPE
- Maximum Relative Error = MAXRE
- Mayer's relation
- MBO fluid @model
- McCain (2011) undersaturated oil isothermal compressibility @model
- MDCV @model
- mdthf (measured depth below tubing head flange)
- Mean Square Deviation = MSD
- Mean Square Error = MSE
- Mean Value = μ = μ1
- Measured Depth = MD (wellbore)
- Measured Length = ML (trajectory)
- Measurement
- Measuring device
- Measuring instrument
- Measuring tool
- Mechanical Defectoscopy
- Mechanical equilibrium
- Mechanical Pressure (physical property)
- Mechanical wave
- Mechanics
- Medium (mechanics)
- Medium Oil (fluid composition)
- Megapascal = MPa (unit)
- Melting point
- Memory well logging
- Merge and Acquisitions = M&A (Business)
- Metamorphic rock
- meter = m (unit)
- Methane = CH4
- Microseismic @survey
- Microspherical Logging (MSFL)
- Middle Time Response = MTR
- Midstream
- Millidarcy = md
- Milligram = mg
- Million standard cubic feet = MMscf
- minute = min
- Mixing Rules
- Mixing Rules for Viscosity
- Mixture
- Mixture component
- Mixture composition
- Mixture density
- Mixture ingredient
- mm (unit)
- Mobile Oil Initial In-Place = MOIIP
- Mobile Oil Pore Volume
- Mobility-weighted fluid density
- Model Description Protocol
- Model Inputs
- Model Matching
- Model Outputs
- Model Prediction
- Model Response
- Model Run
- Model Solver
- Model Validation
- Modified Black Oil fluid @model
- Modified Black Oil Reservoir Flow @model
- Modified Internal Rate of Return = MIRR
- mol (unit)
- Molar fraction
- Molar Mass = M
- Molar volume = Vm
- mole (unit)
- Molecular Concentration = n
- Molecular freedom degrees = f
- Molecular mass (physical property)
- Molecular Weight = M
- Molecule
- Mole fraction
- Momentum equation
- Money
- Monitoring drilling
- Moody Chart
- Motion
- Movable fluid
- MPa
- MRT @sample
- MRT @workflow
- Muddstone
- Mud Filtrate
- Multifinger Caliper = MFC
- Multifrac horizontal well pressure diffusion @model
- Multihase Fluid Mobility
- Multi-layer pressure diffusion @model
- Multilayer Pressure Interference Test @ model
- Multiphase fluid
- Multi-phase fluid
- Multiphase fluid compressibility @model
- Multiphase Fluid vs Fluid Mixture
- Multiphase formation pressure
- Multi-phase pressure diffusion
- Multirate Step Test (MRST)
- Multiwell deconvolution = MDCV
- Multi-well pressure-rate correlations @ review
- Multiwell Retrospective Testing = MRT
- Multi-well watercut history WΣW plot
- Multi-well watercut history YΣY plot
- Muskat - Leverett equation
- MWD
- Petrosky–Farshad (1993) saturated oil formation volume factor Bo @model
- Petrosky–Farshad (1993) saturated oil gas solubility Rs @model
- Pure alkanes properties
- Slightly compressible Material Balance Pressure @model
- Thousand standard cubic feet = Mscf
- μw water viscosity Brill & Beggs correlation @model
- μw water viscosity Likhachev correlation @model
- μw water viscosity Mao-Duan correlation @model
- μw water viscosity McCain correlation @model
- μw water viscosity Meehan correlation @model