fredgrowcock mi swaco drilling fluids

8/12/2019 FredGrowcock Mi SWACO Drilling Fluids

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Primary funding is provided by

and a contribution from Offshore Europe

professionals to serve as lecturers

ona suppor prov e y

Society of Petroleum EngineersDistinguished Lecturer Program

www.spe.org/dl


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How to Stabilize and Strengthen the

.

Distinguished Lecturer Program

www.spe.org/dl


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Presentation Outline

The Lost Circulation Problem

Strategy for Managing Lost Circulation

Wellbore Stress EnhancementApplication Strategies on the Rig

Summary

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The Lost Circulation Problem: High-Risk Operations

ight

Fractured Wellbore

Pressure Gradient / Mud Density eight

Mud

W

Collapsed Wellbore

Weak zone de leted

Frac Gradient

Mud

Mud

Well Inclinat ion0 30 60 90

Deviated Wellbores

Weight

Pore

Pressure

ep e e ones

Deep Water


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The Lost Circulation Problem

Estimated industry cost in the Gulf of Mexico:$1 billion/ r. Worldwide: ~ $ 2 to 4 billion/ r.

On average, 10-20% of the total cost of drilling anHTHP well is expended on mud losses (U.S.

epar men o nergy .

No consistent approach to manage lost circulation.

companies to control lost circulation.

A comprehensive Lost Circulation mitigation and

prevention program is required.

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Managing Lost Circulation: A 4-Tiered Strategy

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Tier I. Best Current or New

Accurate, precise Geomechanics Model, esp.Pore Pressure / Fracture Gradient

Minimum and invariant Equivalent CirculatingDensity (ECD)

Accurate hydraulics profile for pre-drilling & at well site

Good hole-cleanin ractices

Optimized solids control equipment

Casing While Drilling

Expandable Casing/Liner7


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Tier II. which Minimize Losses:

WBM:

Full pressure shielded from tip by

solids filter cake buildup.

OBM/SBM:

Full pressure at fracture tip.

based on Morita et al, SPE 20409


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Tier II. which Minimize Losses:

High Low-Shear-Rate Viscosity (LSRV)

Underbalanced Fluids

Aphron and Mixed Metal Fluids

Minimum and Invariant ECD Soluble or Micronized Weighting Material

- Wellbore Isolation

Silicate, Gilsonite Fluids10


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Tier IV. in Pills or Whole Mud

-

Optimum Bridging Agent Blend for Fluid

different sizes, shapesand properties;

D10 T

D50 T

D90 T

F0.8

0.9

1.0

Particle size distribution

matches distribution of

Brand

Mud

A=Pu

B=Pu

C=Sn

D=O0.6

0.7

izeDistribution

open ngs n roc ;

Used in squeeze or0.3

0.4

0.5

umulativeParticle-S

May be used one timeor on re ular basis Calc

0.1

0.2

while drilling ahead.

12

vg

Max1x10 -2 1x10 -1 1x10 0 1x10 1 1x10 2 1x10 3 1x10 4

Particle Size (microns )


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vs

a es

Most Fibers

Insoluble Salts

MarbleSynthetic

Graphite

am na es Hard,Granular

Fibers

Swellable or

Reactive

Materials

Soft Granules

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Strategies for Strengthening the Wellbore

Physical Wellbore Isolation: Swellable or Reactive Materials

rac ure p so a on rac ure ropaga on es s ance

Chemical

and invert emulsions)

Thermal Increase temp of drilling fluid above bottom-hole static

temp: stiff formations, high thermal expansion

Mechanical Fracture Closure Stress

Hoop Stress Enhancement (Stress Cage)

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Fracture Pro a ation Pressure FPP

OriginalFormationBreakdownPressure(FBP)Leak Off

Pressure

FBP

after

Wellbore

Strengthening

Fracture Gradient (FG)

re

ssur Fracture Closure Pressure (FCP)

(=

Minimum

Horizontal Stress,

Shmin)

meor o ume umpe constant pumprate


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Fracture Closure Stress

High-fluid-loss treatment for existing fractures

pp e as g - u - oss p s or w o e mutreatment (Drill-n-Stress)

Pill may be water-based in a non-aqueous

system May follow with cross-linked polymer plugs or

cement


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As existing fracture is widened,

particles are forced deep within the fracture.

Liquid leaks from the slurry

through the fracture walls or tip.

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As the slurry deliquifies, it consolidates.

The residual solid plug supports the fracture and

.

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Hoop Stress Enhancement

Wellbore is pre-fractured and sealed to preventsubsequent fracturing

Mathematical models are used to design the :calculate the re uired fracture width and article sizedistribution of

drilling (involves solids control management):Continuous addition is much more effective than ills

The formation is pressured every stand to build hoop,


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As fracture is widened, large particles are forced in

and wedged in the fracture mouth to create bridge

Smaller particles come in behind the bridge

and seal the opening

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Trapped fluid f ilters

through permeable walls of fracture

The pressure drops and compressive

forces are transferred to WSM

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Hoop Stress Enhancement Application Cycle

Suitability of Treatment Data CollectionModeling of FractureCreation and Filling

Output:-Fracture dimensions-Formulation of LossPrevention MaterialLessons Learned

Fluids Program-Type of treatment:

*Pills*ContinuousData Collected

-Handling WSM-Fluid property management-Monitoring tools

Slot Tester Sieves

-Mud Pump restrictions

ProgramImplementation

&Analyzed

- own o e too s restr ct on-Lost circulation contingency

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Design of Hoop Stress Enhancement

Fracture Width required to achieve desiredwellbore pressure elastic model:

Desired E uiv. Circ. Densit , or Wellbore Pressure

Rock Properties Poissons Ratio, Youngs Modulus,

Minimum Horizontal Stress (or Fracture Gradient)Well Geometry Depth, Inclination, Hole Size

Acce table t es of WSM

WSM particle size distribution (PSD) andconcentration

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Acceptable

Lar e Tou h and Granular

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Unacceptable

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Continuous Addition of to whole mud is best

For short intervals, bypass the shale shakers

,

The most effective solution: an WSM Recovery System

Screens out drilled cuttin s

Recovers and

recyc es

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Monitoring Hoop Stress Enhancement

Techniques to be used at the rigsite:

Permeabilit Plu in Tests

Wet Sieve Analysis Sand kit determination

Laser Light-Scattering Particle Size

Distribution

Fracture Sealing and WellboreStrengthening tests

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epwater Gulf of Mexico, Above and Below Saltepwater Gulf of Mexico, Above and Below SaltCase History Deepwater Gulf of Mexico

Major challenges

Mud losses> 15,000 bbl/well ,

intervals below the salt!

Wellbore stability

Solution

Strengthen five intervals

- One above the Salt

Drilling ECD

exceeds min

Frac Gradient

- ne n e a- Three below the Salt

Shakers dressed with

[WSM] ~ 15 to 30 lb/bbl

WSM Design- ze ar e- Granular Synthetic Carbons


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Case History Deepwater Gulf of Mexico

No losses in 2900 ft sand section above salt

No losses in 7500 ft salt section, screened up

No losses in 9200 ft sand section below salt

Savings

~ . .losses ~ $ 2.7 MM. Net savings ~ $ 2.0 MM onmaterials alone.

On subsequent 4 wells, similar net savings of ~ $ 2.0MM on materials alone.


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The 4-tier strategy for managing lost circulation

Summary

must be an integral part of well planning

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Society of Petroleum EngineersDistinguished Lecturer Programwww.spe.org/dl

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fredgrowcock mi swaco drilling fluids

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