Part 3

Drilling •  •  •  •  •  •  •  • 

Introduction Rig Types Rig Personnel & Components Drill Bits, Drill Pipe, Fishing Tools Subsurface Pressure Drilling a Hole - Casing Program Well Completion Directional Drilling

©SCA,

LLC

‹#›

What Is This?

©SCA,

LLC

‹#›

Chevron’s recent “Jack 2” discovery Lower Tertiary play in the Walker Ridge area

Photo: Devon Energy Corp.

©SCA,

LLC

‹#›

Deep Drilling!! Sea level

7,000 feet Sea floor

20,000 feet

Chevron’s recent “Jack 2” discovery, 175 miles off the coast 21,000 feet of Louisiana, is over 5 miles below sea level. Total depth = 28,175 feet ©SCA,

LLC

‹#›

Types of Drilling Wells •  Exploration: well to test new exploration opportunity. •  Rank Wildcat: exploratory well drilled significantly away from or deeper than known production.

•  Discovery: a successful exploration well. •  Dry Hole: a well that encountered no hydrocarbons, or insufficient hydrocarbons quantities to justify development.

•  Appraisal: follow-up well drilled to evaluate the commerciality of a new discovery.

•  Development: field wells drilled to develop and produce discovered reservoirs.

•  Injection: wells utilized to inject gas, water or chemicals for production enhancement or waste water disposal.

©SCA,

LLC

‹#›

Drilling •  •  •  •  •  •  •  • 


©SCA,

LLC

‹#›

Rig Types

Water Depth = 300’

Water Depth = 10,000’

8

8

Land Jackup

Semisubmersible “Floater”

Drill Ship Dynamically Positioned

Anchored ©SCA,

LLC

‹#›

Rig Types - Land Rig

©SCA,

LLC

‹#›

Rig Types - Jackup Rigs

©SCA,

LLC

‹#›

Rig Types: Semi-submersible

Seadrill Deepwater http://www.miningtopnews.com/wp-content/uploads/2009/01/seadrill-west-aquarius.jpg

©SCA,

LLC

‹#›

Rig Types: Semi-submersible

©SCA,

LLC

‹#›

Rig Types – Drill Ship

Noble Globetrotter Water depth to 10,000’/3,048 m Well depth to 40,000’/12,192 m (Image: Noble Corp)

Deepwater Discovery Water depth to 10,000’/ 3,048 m Well depth to 30,000’/ 9,144 m (oilrig-photos.com) ©SCA,

LLC

‹#›

Drilling •  •  •  •  •  •  •  • 


©SCA,

LLC

‹#›

Rig Personnel •  Company man: representative of the operator (oil company). •  Offshore Installation Manager (OIM): the most senior manager on board an offshore drilling rig or production platform, responsible for the health, welfare and safety of the personnel of the service company. •  Tool pusher: responsible for maintaining all tools, equipment, supplies, etc!for the drilling operations. •  Driller: in charge of the drilling crew, “driving” the drilling rig, monitor drilling performance and hole conditions to optimize drill rate and avoid hazards. •  Derrick hand: guides the stands of drillpipe into the top of the drill string from a position at the top of the derrick.

©SCA,

LLC

‹#›

Rig Personnel •  Roughneck: works on the rig floor handling the drill pipe during drilling operations. •  Roustabout: handles various jobs including rig maintenance and cleanup. •  Geologist: evaluates cuttings, core and log data from the drilling well and relates to the well prognosis. •  Mudlogger: service company employee responsible for gathering data and collecting cuttings and fluid samples during the drilling of a well to identify possible indications of hydrocarbons (“shows”). •  Mud engineer: responsible for the drilling fluid (“drilling mud”) which lubricates the drill bit and clears cuttings from the borehole.

©SCA,

LLC

‹#›

Rig Personnel •  The number and makeup of the crew staffing a drilling rig varies depending on the location and type of drilling operation. •  Most drilling operations run 24 hours/day to optimize rig use, and there are typically two full crews to work the day shift and the night shift. •  Crews typically work two weeks on and two weeks off, although 28-day shifts are common in remote locations.

©SCA,

LLC

‹#›

Rig Personnel

!"#$%&'()*+ ©SCA,

LLC

‹#›

Rig Components 1. Mud tank (pump) 2. Shale shakers 3. Suction line pipe 4. Mud pump 5. Motor or power source 6. Vibrating hose 7. Draw-works 8. Standpipe 9. Kelly hose 10. Goose-neck 11. Traveling block 12. Drill line 13. Crown block 14. Derrick 15. Monkey board 16. Stand (of drill pipe) 17. Pipe rack (floor)

18. Swivel 19. Kelly drive 20. Rotary table 21. Drill floor 22. Bell nipple 23. Blowout preventer, Annular 24. Blowout preventers, Pipe & Blind ram 25. Drill string 26. Drill bit 27. Casing head 28. Flow line

Components of a Drilling Rig

©SCA,

LLC

‹#›

Rig Components

Rig Floor

Kelly (40’) Kelly Bushing Rotary Table

Drill Pipe (30’)

Kelly and Rotary Table ©SCA,

LLC

277

Rig Components

Rotary Drive System ©SCA,

LLC

‹#›

Mud Circulation System Primary functions of drilling mud •  Cool the drill bit •  Remove cuttings •  Stabilize the well bore •  Balance formation pressure

Mud Pump Stand Pipe

Rotary Hose

Shale Shaker

Mud Pit

Swivel

Annulus

Shale Slide Drill Bit

Reserve Pit

©SCA,

LLC

‹#›

Drilling •  •  •  •  •  •  •  • 


©SCA,

LLC

‹#›

Drill Bits

Tri-cone Tooth Bit ©SCA,

LLC

‹#›

Drill Pipe & Drill Collars

DRILL PIPE connects the bottom-hole assembly (collars & bit) to the rig, to raise, lower, rotate and pump mud to the drill bit.

DRILL COLLARS add extra weight immediately above the drill bit in the drill string to improve penetration rate. ©SCA,

LLC

‹#›

Drilling •  •  •  •  •  •  •  • 


©SCA,

LLC

‹#›

Drilling: The Casing Program Blowout Preventer

36” Hole 30” Conductor Pipe 100’

26” Hole 20” Surface Casing 2000’

17 1/2” Hole 13 3/8” Intermediate Casing 8000’

©SCA,

LLC

‹#›

Drilling: The Casing Program

36” spud bit

26” drill bit ©SCA,

LLC

‹#›

Drilling: The Casing Program

30” conductor casing ©SCA,

LLC

‹#›

Drilling •  •  •  •  •  •  •  • 


©SCA,

LLC

‹#›

Subsurface Pressure – Blowout Pressure Prediction Pressure

Depth

Overburden Pressure Reservoir Pressure

Blowout

Drill Fluid “Mud Weight” ©SCA,

LLC

‹#›

Maconda Blowout – April 2010

©SCA,

LLC

‹#›

Drilling •  •  •  •  •  •  •  • 


©SCA,

LLC

‹#›

Drilling – Well Completion Cement Program

39,600’ of Pipe

30” 100’

Casing Shoe

20” 2500’ 13 3/8” 8000’ 9 5/8” 14,000’

Producing Formation

Drilling The Target Horizon ©SCA,

LLC

‹#›

Drilling – Well Completion Cement Program 30” 100’

39,600’ of Pipe Casing Shoe

20” 2500’ 13 3/8” 8000’ 9 5/8” 14,000’ 7” Liner 15,000’

Perforation Holes Shot in Liner Producing Formation

Perforate the liner and clean up the reservoir ©SCA,

LLC

292

Drilling – Well Completion •  Completion is the process in which the well is prepared to produce hydrocarbons. •  Perforations are made through the casing to allow formation fluids to flow into the well bore from the producing reservoir. •  Completion fluids are pumped into the reservoir to clean up damage caused during drilling and enhance reservoir flow. •  A packer is set above the perforations to isolate them from the rest of the wellbore. •  Production tubing inside the casing then conducts the hydrocarbons through the packer to the surface.

©SCA,

LLC

‹#›

Well Completion: Perforations

©SCA,

LLC

‹#›

Well Completion: Tubing

•  Packer: set above the perforations to isolate them from the rest of the wellbore. •  Production tubing: conducts the oil through the packer(s) to the surface.

©SCA,

LLC

‹#›

Casing & Tubing, Top View Formation

Cement

Conductor 20” Surface 13 3/8”

Intermediate 9 5/8” Production tubing

Liner 7”

©SCA,

LLC

‹#›

Fracture Stimulation •  Hydraulic fracturing (“fracing” or a frac job): pumping pressurized fluid into reservoirs to create fractures which allow crude oil and natural gas to flow from the reservoir into the well bore. •  Fractures: induced fractures extend into the reservoir, increasing the surface area of the formation exposed to the borehole and therefore the rate at which reservoir fluids can be produced. •  Proppant: fractures are kept open by inclusion of a proppant, commonly a uniformly sized sand. Improved fracture stimulation technology has allowed tight gas sand and “unconventional” shale reservoirs to produce in commercial rates and volumes.

©SCA,

LLC

‹#›

Fracture Stimulation

©SCA,

LLC

‹#›


Fracing or Frac job

©SCA,

LLC

‹#›


Ceramic Proppant

©SCA,

LLC

‹#›

Environmental Challenges

©SCA,

LLC

‹#›

Fracing – Environmental Impact •  This process has been used for more than 60 years in over a million wells •  Surface casing protects the groundwater aquifer behind steel and cement •  Hydraulic fracturing generally takes place thousands of feet underground, below multiple layers of impermeable rock and well below drinking water aquifers. •  Hydraulic frac fluid is ~99 percent water and proppant, and ~1% chemical additives (found in household products). •  Most of the sand or ceramic proppant remains in the reservoir to hold open the fractures. •  Most of the water and additives flow back to the surface where they are recycled or disposed of at permitted waste water disposal sites.

©SCA,

LLC

‹#›

Drilling •  •  •  •  •  •  •  • 


©SCA,

LLC

‹#›

Advantages of Directional Drilling •  Drilling at an angle (or horizontally) increases the exposed section of well bore through the reservoir. •  Access multiple targets that are not vertically stacked •  Access reservoirs where surface access is difficult or not possible, such as under a city, airport, lake, or environmentally restricted area. •  Drill multiple wells from a single surface location to limit surface impact (e.g. arctic environments), or eliminate the need for multiple production facilities (e.g. offshore platform). •  “Relief wells" can be drilled from a safe distance to control a “blow out” well.

©SCA,

LLC

‹#›

Applications of Directional Drilling After Leroy & Leroy 1977

A

B

C

D

E

F

G

H

I

J

A. Multiple wells offshore or platform B. Shoreline drilling

E. Stratigraphic trap F. Relief well control

C. Fault Control D. Inaccessible location

G. Straightening hole & side tracking H, I, J Salt dome drilling ©SCA,

LLC

‹#›

Horizontal Drilling in Unconventional (Resource) Plays Horizontal drilling is used in shale gas plays to: ! Increase well bore exposure to reservoir ! Intersect more natural fractures ! Avoid water bearing zones ! Accelerate production & increase EUR/well

©SCA,

LLC

‹#›

Horizontal Drilling in Conventional Fields Horizontal drilling increase well bore exposure to the reservoir, accelerates production and increases EUR/well.

©SCA,

LLC

‹#›

Drilling - Summary •  •  •  •  •  •  •  • 

Introduction Rig Types Rig Personnel & Components Drill Bits, Drill Pipe, Fishing Tools Subsurface Pressure Drilling a Hole - Casing Program Well Completion Directional Drilling ,-./0+

©SCA,

LLC

‹#›

Advantages of Directional Drilling

Source: API Oil & Gas Primer, 11/2008

©SCA,

LLC

‹#›

Please do not turn the page

©SCA,

LLC

‹#›

Well Data Acquisition •  Types of Well Data •  Relating Log Data to Geology •  Relating Log Data to Seismic Data

©SCA,

LLC

‹#›

Types of Well Data The following processes are used to acquire data from drilling wells to analyze subsurface formations: •  Mud logging •  Wireline logging •  MWD (Measurement While Drilling) •  Coring

©SCA,

LLC

‹#›

Mud Logging •  Mud logging is the evaluation of formation cuttings created at the drill bit and transported to the surface by the drilling mud. •  The cuttings are caught at the shale shaker and placed in small bags at regular intervals. •  Analysis is done using a microscope and a ultraviolet box to look for indications of oil stains (florescence). •  The drilling mud is also analyzed for hydrocarbon gases using a gas chromatograph.

©SCA,

LLC

‹#›

Mud Logging

Mud Pump Stand Pipe

Rotary Hose

Shale Shaker

Mud Pit

Swivel

Annulus

Shale Slide

Reserve Pit

Mud Circulation System ©SCA,

LLC

‹#›

Mud Logging

Shale Shakers

©SCA,

LLC

‹#›

Mud Logging

Cuttings ©SCA,

LLC

‹#›

Mud Log

Show: The presence at a certain depth of oil or gas in the drilling mud, possibly indicating a productive zone.

©SCA,

LLC

‹#›

Overview of Wireline Logging Depth Measurement

Draw Works Wellhead

Digital Recording

Cable Winch Wireline Downhole Tools

©SCA,

LLC

‹#›

Wireline Logging

Logging Truck ©SCA,

LLC

‹#›

Wireline Logging

Logging Tools

©SCA,

LLC

‹#›

Wireline Logging

Logging Tools going in the hole ©SCA,

LLC

‹#›

Logging While Drilling Advantages: •  Measure formation properties before drilling fluid invasion. •  Obtain data from well bores that are difficult to log with wireline tools (e.g. horizontal wells). •  In some cases alleviates the need to run wireline logs. •  Widely used for geosteering of horizontal wells in unconventional resource plays. !  note: Geosteering is the process of adjusting borehole orientation during drilling to target geological objectives based on mud logging data and information gathered by MWD and LWD tools.

©SCA,

LLC

‹#›

Types of Wire line Logs •  •  •  • 

Electric (Resistivity) Logs Porosity Logs Lithology Logs Acoustic Logs

©SCA,

LLC

‹#›

Wireline Logging Resistivity Log

Neutron-Density Log Gamma Ray

Neutron

Resistivity

Density

Caliper

©SCA,

LLC

‹#›

Types of Wire line Logs Log Name: Measures: Electric resistance to electric (Resistivity) current of the rocks and fluids in the formation near the borehole SP electrical potential (Spontaneous difference between mud in Potential) the well opposite different formation lithologies and a stake at the surface near the borehole Gamma Ray natural emission of gamma rays from the formations

Density

Neutron

Acoustic (Sonic)

How it works: Indicates: gas and oil are resistant to electrical presence of hydrocarbons in the current and saline formation water reservoir. conducts electrical current electrical potential varies due to formation properties

distinguishes shales which have naturally high levels of radioactivity from other formation with typically low gamma ray signatures density contrast between gamma ray absorption is a function minerals in the formation of matter per unit volume (formation and fluids in the pore space density). neutron detectors measure rate of loss is inversely related to energy loss as neutron the amount of hydrogen present in source irradiates the the pore fluids (water and formation and emitted hydrocarbons) neutrons are absorbed formation travel time tool emits sound waves that travel (velocity) from a source to a receiver in the wireline tool

permeability, lithology and depositional environment

shales vs. other lithologies, organic richness

porosity, if both mineral and fluid densities are known porosity

lithology, porosity and two-way travel time which is used for seismic time/depth conversion ©SCA,

LLC

‹#›

Determining “Pay” •  A reservoir or portion of a reservoir that contains economically producible hydrocarbons i.e. capable of "paying" an income. •  Sometimes called pay sand or pay zone. •  The overall interval in which pay occurs is the gross pay interval. •  The intervals within the gross pay zone that meet criteria for producing hydrocarbons such as minimum porosity, permeability and hydrocarbon saturation are called the net pay interval. www.glossary.oilfield.slb.com/Display.cfm?Term=pay

©SCA,

LLC

‹#›

Log Evaluation

©SCA,

LLC

‹#›

Contour Map on Geologic Surface

©SCA,

LLC

‹#›

Mapping Using Well Logs

-3000’

0’

-4000’

-5000’

}100’

-1000’

SSTVD

-2000’

2000 MD’

3000 MD’

-3000’ 4000 MD’

-4000’ -5000’

5000 MD’

6000 MD’

©SCA,

LLC

329

Mapping Directionally Drilled Wells

Measured Depth (MD)

True Vertical Depth (TVD)

©SCA,

LLC

330

Measurement While Drilling (MWD) & Logging While Drilling (LWD)

©SCA,

LLC

‹#›

Logging While Drilling (MWD & LWD) •  Sophisticated (and relatively expensive) logging tools that are physically located in the bottom hole drilling assembly. •  Measurements include borehole temperature, pressure and directional data (MWD), and many wireline log measurements such as resistivity, porosity, gamma ray and velocity data (LWD). •  The measurements are made in real time, stored in solid-state memory, and transmitted to the surface by digitally encoded mud pulses. Mud-pulse telemetry system

Smith International PathMaker 3-D Rotary Steerable System

©SCA,

LLC

‹#›

Coring: Conventional Cores •  Conventional, full diameter or whole core allows for accurate determination of formation rock properties and fluid saturations. •  Whole core is a cylinder of rock, 3" to 4" in diameter and up to 60 feet long acquired in a core barrel. •  The core barrel is a hollow pipe tipped with a circular, diamond bit that cuts the core and retains it for retrieval to the surface. •  Conventional core is invaluable for reservoir evaluation although time consuming and expensive to obtain. •  Coring takes place at pre-determined intervals, before objective has been penetrated.

©SCA,

LLC

‹#›

Coring: Conventional Cores

©SCA,

LLC

‹#›

Coring: Sidewall Cores •  A core gun has numerous, hollow steel cylinders mounted along its sides, attached by short cables. •  The core cylinders are propelled laterally into the formation at selected depths by explosive charges. •  The cables then pull the cylinders containing small samples (1” diameter x 1.75” length) from the well bore wall and transports them to the surface. •  Sidewall cores allow sampling at many points in the well bore after wireline logs have been acquired. •  Sidewall cores are generally less expensive •  Sample recovery is often poor, and the potential to stick the tool in the hole is relatively high.

©SCA,

LLC

‹#›

Sidewall Cores

©SCA,

LLC

‹#›

Well Data Acquisition •  •  •  •  • 

Types of Well Data Mud Logging Wireline Logging MWD Logging Core: Conventional & Sidewall

©SCA,

LLC

‹#›

Please do not turn the page

©SCA,

LLC

‹#›

Reservoir Engineering •  •  •  • 

Basics Drive Mechanisms Evaluation of Reserves & Resources Reservoir Modeling and Simulation

©SCA,

LLC

‹#›

Basic Reservoir Terminology: Porosity, Permeability & Water Saturation •  Porosity: A measure of the void spaces in a reservoir recorded as a percentage between 0 and 100%. •  Fracture porosity: Associated with a fracture system related to faulting or induced fractures (frac job), creating porosity in rocks like brittle shales that lack primary porosity •  Permeability: A measure of the ability of a reservoir to transmit fluids through connected pore space, designated by the darcy (D), or more commonly the millidarcy (mD) or 0.001 darcy. •  Water Saturation: The fraction of the pore space that is occupied by formation water, expressed in %.

©SCA,

LLC

‹#›

Sandstone Reservoirs

Pore space

Sand Grains Permeability

Good Porosity = Lots of Space for Oil & Gas ©SCA,

LLC

‹#›

Hydrocarbon Reservoirs Porosity Gas/ Oil Contact Oil/ Water Contact

Sand Grain ©SCA,

LLC

‹#›

Reservoir Drive Mechanisms+ •  The natural forces in the reservoir that displace oil and gas out of the reservoir, into the well bore and up to the surface are called reservoir drive mechanisms. •  A pressure differential or “pressure sink” must exist between the reservoir and the wellbore in order for reservoir fluids to be produced. •  As the reservoir is produced, pressure is naturally maintained by one of these processes: !  !  !  ! 

Water influx from an aquifer Fluids (oil and gas) expanding within reservoir to occupy volume Reduction in volume, i.e., reservoir collapse Fluid flowing from one elevation to another, gravity drainage

©SCA,

LLC

‹#›

“Edge” Water Drive

As the oil is produced, water residing in the reservoir will “drive” or sweep the oil toward the well bore. Additional water continues to enter the system (recharge). ©SCA,

LLC

‹#›

Reserves Evaluation Methods Common methods for determining the volume of hydrocarbons in a reservoir include: •  Decline Curve Analysis •  Volumetrics

©SCA,

LLC

‹#›

Decline Curve Analysis (Mature Reservoirs)

+

Barrels of oil and water per month

Economic Limit

Decline Curve

Projected EUR 83,300 bbls.

Field Production Rate Decline Curve ©SCA,

LLC

‹#›

Reserves Evaluation: Volumetrics •  Geoscientists and reservoir engineers work together utilizing detailed reservoir maps and well bore data to estimate the original barrels of oil contained in the reservoir (OOIP). •  Stock Tank Oil Initially In Place (STOIIP) refers to the original volume of oil in the reservoir converted to volume at surface conditions. •  A recovery factor is estimated utilizing the permeability of the formation and the reservoir drive mechanism. •  The recovery factor is applied to the STOIIP to provide a deterministic (equation driven) estimate of the amount of oil that will ultimately be produced. ©SCA,

LLC

‹#›

Estimating Recoverable Reserves Rock Volume =70%

Area (acres) Net Pay (feet)

Gross Reservoir Volume

Pore Volume Porosity = 30%

Water Saturation Sw = 50% Oil in Place OOIP = 50%

!'("1'23+45(6"2+7'8'&7*+"&+ 2'*'21"92+82'**#2':+2';5;'+ "9;+"2+$5*+*56#25'+6251';;9&$+56+5+('2659&+1';"(963+9&+"27'2+6"+*#*8'&7+6%'+852@=! ++ D%9*+("&79
LLC

‹#›

Evolution of channel levee systems in the MarsUrsa region. (A) Turbidity currents incised the blue unit in phase 1. (B) Channel deepened, and levees were deposited in phase 2. C) Rotational channel margin slides formed by base failure and forced blue unit and levee material to slide down on circular failure planes and forced the toe thrust up through the channel floor. (D) Levee growth, rotational sliding, and channel excavation continued synchronously to maintain a conveyor belt process in phase 4. Channel backfilling developed at the end of phase 4 in response to changes in base level. The sandy nature of turbidity currents is reflected in the sand-rich nature of the channel fill.+

D#2"&95&+APO+K9;;9"&+W'52*+X$"B+

TANO COMPLEX+

+ AJKLMJNO!FJN+ YZZ+)=[+ OZZ:ZZZ+5(2'*+

Mahogany #1 (Jubilee Field) – Discovery Well+

Stacked turbidites of Turonian age Net oil pay 95m (>300’) Individual pays up to 35m (>100’) thick Excellent reservoir characteristics High well deliverability (Mahogany 1 Tested at >20,000bopd)

\.+*'9*=9(+#*'7+ ?"2+ =5889&$+6%'+ ']6'2&5;+ $'"='623:+5&7:+56+ *"='+']6'&6:+6%'+ 9&6'2&5;+$'"='623+ "?+6%9*+ 2'*'21"92:+@%9(%+ @5*+8523+ 5+3"#&$'2+ 6#2>9796'+(%5&&';S+ "&+6%'+29$%6:+ Y.+*'9*=9(+#*'7+ ?"2+=5889&$+@56'2+ 5&7+ $5*+*56#25 P=!DVLXYZ[! Pressure & Temperature

L)(!V+;!

Gas/Oil Contact

Increasing

W$-+&!V+;!

Oil/Water Contact

GPQ%!F!R!IQ%!D!

Oil Window STQ%!F!R!GUT%!D!

Generation

Subjective Risk and Uncertainty Analysis •  The evaluator can establish a single Risk Factor and Uncertainties of a Low, Mid, and High side Reserve case based on estimated (professional opinion) parameters. •  For a prospect it may have Risk of 20% COS with the main uncertainty being Area Low-200 acres, Mid-600 acres, and High 1000 acres with Reserves varying with these parameters only. •  For a development well it may have Risk of 80% COS, with the main uncertainty being Recovery Factor, Low-100 BAF, Mid 250 BAF, High 400 BAF with Reserves varying with these parameters only.

Statistical Analysis of Field Size Data (Uncertainty) Field # 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Date 1972 1973 1974 1975 1975 1977 1978 1978 1980 1983 1983 1983 1984 1985 1985 1987 1988 1988 1990 1991

EUR MMBO 12 24 11 1.2 3.4 2.2 3.4 1.4 1.8 0.9 0.7 0.8 2.3 0.7 1.2 0.5 0.6 0.4 0.5 0.2

Cutbank Formation Trend Data Summary measures for selected variables EUR Count 20.000 Mean 3.460 Median 1.200 Standard deviation 5.833 Minimum 0.200 Maximum 24.000 Range 23.800 Variance 34.020 Mean absolute deviation 3.662 Skewness 2.788 Kurtosis 8.149

Which is the best measure of expected field size?

Statistics and Probability

•  Unfortunately no discussion of Probability can avoid at some point the use of statistical methods. •  While Probabilities are usually expressed as a decimal or fraction they are often derived from statistical analysis. •  Probabilities can be verified by repeated trials (simulation).

*#-.,./-&)01-&+,2,)%3)42"&5) *26")7-#-)) Probability Plot P1

Probability

P10

Descriptive Statistics Derived from Probability Analysis

P50

Swanson's

P90

1000

100

10

1

.10

P99 0

P99 P1 P90 P10 P50 P Mean

0.07 49.66 0.30 11.32 1.85 3.46 5.17

Statistical Analysis of Trend Field Size Time Series Data - is it Relevant? EUR vs Time

100

What would be the expected field size for a Prospect to be drilled in 2010?

Mean Field Size 3.46 MMBO

MMBO

10

1

Discoveries are getting smaller with time 0.1 1970

1975

1980

1985 Year

1990

1995

Statistical Analysis of Inputs Associated with Uncertainty & '(")* '( ,./, ,./, ,2/3 ,+/2 ,./4 ,3/1 ,./4 ,-/, ,5/2 ,-/1 ,-/,2/. ,5/5 ,-/, 04/4 00/. ,+/5 ,./3 ,3/3 ,5/+ ,2/3 ,./1 04/, 0,/3 ,5/+ ,+/+ ,+/1 00/2 ,+/+

Data

Graphical Display (Histogram or Frequency Distribution)

40 35 30

Frequency

! "#$% +,-, +,-0 +,-1 +,-3 +,-+,-+ +,-2 +,-. +,-5 +,+4 +,+, +,+0 +,+1 +,+3 +,++,++ +,+2 +,+. +,+5 +,24 +,2, +,20 +,21 +,23 +,2+,2+ +,22 +,2. +,25

! "##$%&'#($) "%() '*+%') (,(- .(/'0$%1$2,() ! "#$%& "# ! "'() *++,+++ -$.( */,0+1 -$23.( */,/4+ 5 ).(2.#262$73.)3"( 8,+98 -3(3:': *8,18/ -.;3:': 88,/9< = .(>$ *+,