CAN MUDLOGGING SHOWS BE QUANTIFIED?

CAN MUDLOGGING SHOWS BE QUANTIFIED? Bill Donovan, PE Donovan Brothers Incorporated Automated Mudlogging Systems Our Corporate Motto WE DON T PASS GAS 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 1 0f 58

OVERVIEW Field study results Definitions and theory Resource comparison Mudlogging gas content Factors influencing mudlogging Calibrating the system 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 2 0f 58

PRB CBM Field Study Results 55 wells with Mudlog GC (green) 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 3 0f 58

PRB CBM Field Study Results Common form of volumetric gas in place for shale and coal G = gas in place (MCF) A = drainage area (acres) H = thickness (feet) ρ b = bulk density (gm/cc) GC = gas content (scf/ton) G 1.3597 A H b GC 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 4 0f 58

PRB CBM Field Study Results Back calculated gas content is based on cumulative production and/or estimated ultimate recovery (EUR) G is cumulative production or EUR A is the spacing unit H and ρ b are from logs GC 1.3597 G A H b 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 5 0f 58

PRB CBM Field Study Results 55 wells with Mudlog GC (green) Cumulative Production GC (blue) 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 6 0f 58

PRB CBM Field Study Results 55 wells with Mudlog GC (green) Cumulative Production GC (blue) Estimated Ultimate Recovery GC (red) 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 7 0f 58

PRB CBM Field Study Results 55 wells with Mudlog GC (green) Cumulative Production GC (blue) Estimated Ultimate Recovery GC (red) Isotherm Estimated GC (purple) 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 8 0f 58

OHIO Can Mudlogging Shows be Quantified? Marcellus Shale HZ Well Results Ty Taylor s WESTMORELAND Clemson MS Thesis WEST VIRGINIA PENNSYLVANIA MARYLAND 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 9 0f 58

Marcellus Shale HZ Well Results MAHANTANGO SH MARCELLUS SH Ty Taylor s Clemson MS Thesis 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 10 0f 58

Marcellus Shale HZ Well Results Ty Taylor s Clemson MS Thesis 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 11 0f 58

TG (gas units) Can Mudlogging Shows be Quantified? Marcellus Shale HZ Well Results 600 500 400 Ty Taylor s Clemson MS Thesis 300 200 100 0 TG Mean TG (TRAP) Mean NORMALIZE MUDLOGS ON MATAHANGO SH 1 2 3 4 5 6 7 8 9 10 11 12 Well 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 12 0f 58

18 Month Production (MCF) Can Mudlogging Shows be Quantified? Marcellus Shale HZ Well Results 2,000,000 1,600,000 1,200,000 800,000 400,000 R² = 0.87 0 2,000,000 4,000,000 6,000,000 Ty Taylor s Clemson MS Thesis TG (TRAP) sum (gas units) 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 13 0f 58

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Definitions and Theory Define mudlogging Define mudlogging gas measurements Percent Equivalent Methane in Air (% EMA) and Units EMA Explain why mudlogging is effective Compare resources for different reservoirs 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 16 0f 58

Definitions and Theory Define mudlogging and a mudlog A mudlog is a record over time of rig functions, gas and cuttings The basic mud log records: 1) drilling rate, 2) gas measured at the mudlogging unit and 3) cutting properties such as lithology and the presence of oil A mudlog presents the above properties and others as a function of depth 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 17 0f 58

Definitions and Theory EQUIVALENT METHANE IN AIR (% EMA) is a measure of methane in air at the measurement point (the mudlogging unit) expressed as a percent of methane in the air sample or expressed differently as10,000 parts per million methane by volume Calibrated and measured at the mudlogging unit, the whole system is not calibrated Although related to mudlogging gas content, % EMA is not a measure of gas in the formation or drilling mud Other hydrocarbon gases are presented as methane Typically 100 Units EMA equals 1% EMA 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 18 0f 58

Definitions and Theory MUDLOGGING IS EFFECTIVE BECAUSE: Gas is measured at the surface under STP Gas is insoluble in water and drilling mud Gas expands as it travels to the surface Mudlogging is independent of theories and models 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 19 0f 58

Definitions and Theory MUDLOGGING IS EFFECTIVE BECAUSE: Gas is measured at the surface under STP Gas is insoluble in water and drilling mud Gas expands as it travels to the surface Mudlogging is independent of theories and models Surface gas volume for one cubic foot of gas or gas saturated water at certain depths 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 20 0f 58

Definitions and Theory MUDLOGGING IS EFFECTIVE BECAUSE: Gas is measured at the surface at STP Gas is insoluble in water and drilling mud Gas expands as it travels to the surface Mudlogging is independent of theories and models 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 21 0f 58

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3 Perfed Can Mudlogging Shows be Quantified? Perfed 3 1,124-1,127 Foam fraced w/18k# 10-20 sand Fruitland Coal Pictured Cliff SS 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 24 0f 58

Resource Comparison The next five slide present the amount of gas liberated and brought to the surface for coal, shale, oil and gas reservoirs. The and colored bars to the left show and values relative to the reservoirs. All slides have the same format and vertical scales Again the conclusion reached is that both conventional and unconventional hydrocarbon reservoirs liberate gas in quantities significantly higher than reservoirs containing water 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 25 0f 58

Resource Comparison 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 26 0f 58

Resource Comparison 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 27 0f 58

Resource Comparison 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 28 0f 58

Resource Comparison 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 29 0f 58

Resource Comparison 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 30 0f 58

Mudlogging Gas Content Methodology The requirements to calibrate mudlogging show are: 1) The cubic feet of acetylene generate per pound of calcium carbide (yield) 2) Calibrate the mudlogging gas sensor with both acetylene and methane 3) The peak gas reading of a carbide lag using a measured amount of carbide 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 31 0f 58

Mudlogging Gas Content Methodology The requirements to calibrate mudlogging show are: 4) The gas units during a mudlog show 5) The bit diameter 6) The drilling rate during a mudlog show 7) Simple mathematical computations to calculate gas liberated per minute and rock volume drilled per minute 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 32 0f 58

Mudlogging Gas Content Methodology A measured amount of Calcium Carbide reacts with water to make known amount of acetylene gas: CaC 2 + H 2 0 = C 2 H 2 +CaO Before mudlogging a calibration using both acetylene and methane establishes a relationship between the gases for the mudlogging unit s gas sensors Before and after the zone of interest is drilled a known amount of Calcium Carbide (acetylene) is put in the drill string during connections and pumped to the surface. The peak gas value is recorded Using this data, a gas show in units EMA can be converted to SCF of gas liberated while drilling 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 33 0f 58

Mudlogging Gas Content Methodology The hole volume is known, therefore, SCF/formation bulk volume (ft 3 ) can be calculated along with BCF/section or MCF/acre-foot. These are the standard measures of used in volumetric reservoir calculations If the formation density is known, gas content (SCF/Ton) can be calculated If Bg or Bo, the gas expansion factor or the oil shrinkage factor, is known reservoir hydrocarbon foot (SoPhieH or HCF) along with Bvg or reservoir gas porosity can be calculated 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 34 0f 58

Mudlogging Gas Content Methodology 0.5 cup of calcium carbide yields 1.268 SCF acetylene 125 units of acetylene reads 250 units EMA in the mudlogging unit 0.5 cup of calcium carbide in a connection before the zone yields 200 units of acetylene Calculate a conversion factor from the above data and Avogadro's Law Conversion factor 0.01268 SCF CH 4 /1 UNIT EMA 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 35 0f 58

Mudlogging Gas Content Methodology Calculate a conversion factor from data on the last slide and Avogadro's Law From Carbide Manufacturer From Carbide Lag From Different % s of CH 4 and C 2 H 2 Gas Tested on Sensors 1.268 SCF 0.5 CUPS C2H CaC 2 2 0.5 CUPS 250 Units CaC C H 2 2 2 250 125 Units Units C2H2 EMA 1 SCF 1 SCF CH C H 2 4 2 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 36 0f 58

Mudlogging Gas Content Methodology Calculate a conversion factor from data on the last slide and Avogadro's Law. Conversion factor = 1.268 SCF C 2H 2 1.268 SCF CH4 0.5 CUPS CaC 0.5 CUPS CaC2 1.268 SCF C2H 2 250 Units C2H 250 Units C2H 1.25 % C H 2 2 2 1.25 % CH4 125 EMA CH Conversion factor = 1.25 % C2H 1.25 % CH 0.01268 SCF CH4 /1 UNIT EMA 4 4 2 2 2 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 37 0f 58

Mudlogging Gas Content Methodology Gas reading in the zone 570 UNITS EMA/minute Calculate gas liberated per minute in the zone by multiplying gas reading by the conversion factor 570 UNITS EMA /minute X 0.01268 SCF/UNIT EMA= 7.23 SCF/Minute 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 38 0f 58

Mudlogging Gas Content Methodology Penetration rate in the zone is 0.5 minutes/foot Hole diameter is 8.5 inches Calculate the hole bulk volume (BV) drilled per minute Hole Volume/Minute = 0.78813 BV Cubic Feet/Minute 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 39 0f 58

Mudlogging Gas Content Methodology Divide the gas liberated per minute by the hole volume drilled per minute 7.23(SCF/Minute) / 0.78813(BV CF/Minute) = 9.17 SCF/BV CF Conversion factors can be used to calculate BCF/Section foot or MCF/Acre foot 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 40 0f 58

Mudlogging Gas Content Methodology Zone density is 1.4 gms/cc Convert hole BV CF to Tons by using density Gas content 210 SCF/Ton Zone depth 1,000, Bg = 36.4 Convert SCF to Reservoir CF by using Bg Bulk Volume Mudlog Gas 0.25 CF/BV or 25% 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 41 0f 58

Factors Influencing Mudlogging The factors which influence mudlogging can be grouped into two general categories: Deterministic factors (hole size, drilling rate, etc.) Indeterminate factors (flushing, background gas, surface losses, gas trap performance) Carbide calibration accounts for all factors 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 42 0f 58

Factors Influencing Mudlogging Deterministic factors affecting mudlog gas are: Gas in the formation Hole size Drilling rate Mud pump rate Gas expansion 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 43 0f 58

Factors Influencing Mudlogging If all other factors are equal, doubling the gas in the formation doubles the gas show 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 44 0f 58

Factors Influencing Mudlogging If all other factors are equal, doubling the hole diameter, quadruples the gas show 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 45 0f 58

Factors Influencing Mudlogging If all other factors are equal, doubling the drilling rate, doubles the gas show 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 46 0f 58

Factors Influencing Mudlogging If all other factors are equal, doubling mud pump rate, decreased by one half the gas show 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 47 0f 58

Factors Influencing Mudlogging If all other factors are equal, doubling the depth of the formation doubles the gas show in conventional reservoirs 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 48 0f 58

Factors Influencing Mudlogging Indeterminate factors are: Recycled gas (minor) Contaminated mud (seldom) Formation flushing (minor) Loses while drilling (seldom) A kick while drilling (seldom) Uphole kicks or loses (seldom) 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 49 0f 58

Factors Influencing Mudlogging More indeterminate factors are: Cuttings not fully releasing gas (minor) Surface losses (major) Gas trap design (major) Temperature (major) Wind (seldom) Miscalibrated sensors (seldom) 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 50 0f 58

GAS IN THE MUD GAS AT THE MUDLOGGING UNIT Factors Influencing Mudlogging Gas trap efficiency and measurement stability is the largest cause of mudlogging error. See the SPE, Williams and Ewing article. 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 51 0f 58

Factors Influencing Mudlogging Improved Methods for Samplings Gas and Drill Cuttings, Williams and Ewing, SPE FE, June 1989 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 52 0f 58

Factors Influencing Mudlogging GRI Gas Measurements During Mud Logging Operations 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 53 0f 58

SOLUBILITY AT TEMPERATURE/SOLUBILITY AT 180 DEGREES FAHRENHEIT Can Mudlogging Shows be Quantified? Factors Influencing Mudlogging EFFECT OF TEMPERATURE ON THE SOLUBILITY OF GAS IN WATER 10 8 6 CH4 @ T/ CH4 @ 180 F C2H2 @ T/ C2H2 @ 180 F 4 2 0 0 50 100 150 200 250 TEMPERATURE (DEGREE F) 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 54 0f 58

Factors Influencing Mudlogging GRI Gas Measurements During Mud Logging Operations 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 55 0f 58

Factors Influencing Mudlogging Notice all the potential errors: 100 units of gas in the mud could read as high as 200 units or as low as 3 units due to gas trap design Gas losses as much as 40% due to loss in the flow line Gas losses as much as 50% due to wind A six fold change in methane solubility in water from 40ºF to 180ºF All of these losses can be normalized or compensated for by the use of calibrated carbide lagging. The next slide shows that acetylene behaves like methane over a wide range of conditions. If carbide lag results are consistent, it indicates good quality mudlogging 24/January/201 4 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 56 0f 58

SOLUBILITY RATIO (C2H2/CH4) Can Mudlogging Shows be Quantified? Calibrating the System SOLUBILITY OF GAS IN WATER 80 70 RATIO 60 50 40 30 20 10 0 0 50 100 150 200 250 TEMPERATURE (DEGREE F) 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 57 0f 58

Mudlogging is an effective evaluation tool If you have questions or comments contact me Bill Donovan (303) 794-7470 donovan@mudlogger.com www.mudlogger.com 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 58 0f 58

After Gary Larson School for Gifted MUDLOGGERS 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 59 0f 58

Walt Kelly 24/January/2014 Donovan Brothers Inc. Automated Mudlogging Systems SM Slide 60 0f 58