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Well Test ObjectivesWell Test Objectives1. Identify and Obtain reservoir fluids; oil, gas

& water

2. Determine basic reservoir parametes;

productivity (PI), permeability(k), skin (S),initial Resv. Pressure (P*) & Resv. Temp.

3. Well potential & deliverability (gas well) : It

may be mandatory to proof fieldcommerciality

4. Boundary & irregular conditions Reservoir(GOC, OWC & Reservoir Limit)

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WELL TESTING METHODSWELL TESTING METHODS

HOLE CONDITION:

OPEN HOLE

CASED HOLE

TOOLS RUN IN HOLE :

WIRELINE TESTING : RFT, MDT & DST (IT WAS)

PRODUCTION TEST WITH COMPLETION STRING

IN PLACE : DST

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Surface Test Equipment

Downhole Test

Equipment & Tool

DST & TCP

WELL TESTING SCHEMATIC

at

Cased Hole

Subsea Safety

Equipment

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DOWNHOLE TESTING EQUIPMENT

Open-Hole Sampling EquipmentRDT & RCI are equivalent with RFT/MDT

Baker RCI

Halliburton RDT

Formation Test Tool (FTT) sample

chambers hold 420cc to 3 gallons of

reservoir f luid depending on make and

model.

Open hole samples aid production and

facili ty designs and are sometimes used

for PVT studies.

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1ST GENERATION

RFTREPEATED FORMATION TESTER

- unlimited pressure survey

- 1 to 2 fluid sampling

2ND GENERATION

MDTMODULAR FORMATION DINAMIC

TESTER

- unlimited pressure survey- many f luid sampling (unlimited?)

- able to identify fluid type

- able to replace(pump out)

unrequired fluid sampleSCHLUMBERGER

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DOWNHOLE TESTINGEQUIPMENT

RFT / MDT

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Mud pressure

Reservoir pressure

Build-up pressure

Example RFT Record

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Wirelinepen Hole Testing

FT/MDT/RDT/RCI/etc. To identify the reservoir

pressure

To identify the fluid content

To estimate the permeability

To estimate the productifity To define the fluid contact (OWC,

OGC and GWC if any)

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Fluid Contact Determination

with fluid gradient from RFT

oil

water

RFT depth

WaterG

radient0.433ps

i/ft

pressure

de

pth

OilG

radient0

.367psi/ft

OWC

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Performing Well Testith DST Clean up (flow)

Shut-in

Main flow (one period orflow-after-flow, flowingtest with 4 to 5 different

choke size) Main Build up (shut-in)

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Selective Layer Testing

8 1/2 7 @ 17690

12 1/4

17 1/2

9 5/8 @ 15500

26

Layer B

Layer A

20 ft @ 500

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Example :TEST STRINGDST TCP

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Example : Pressure Testing Result

Build up data analysis

K = 375 mD

S = 21 P = 4200 psia4050[psia]

40 60 80 100 120

45000

[Ms

cf/D]

Production Period

Build up period

Pressure, psia

rates

Sanding Control

Test

Testing time, hrs

[Ms

cf/D]

45000

4050

[psia]

40 60 80 100 120

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Well Productivity

AOFP = 344 MMscf/d

CGR = 24.5 STB/MMscf/d

Tested gas and condensate rates can be

increased to 125 MMscf/D and 3100 BPD

2.5E+5

IPR plot3500

50000

1500

1.5E+5 3.5E+52.5E+5

Gas Rate, Mscf/d

Pre

ssure,psi

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Testing Risk Factors Layers communication due to

poor cement bond

High pressure and temperatures

(over 350F)

Pressure and fluid loss through

packers

Annulus-tubing fluid

communication

Water coning or sanding

Layers crossflow

THE ROLE f

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THE ROLE of WELLSITE/DEVELOPMENT GEOLOGIST (DG)in WELL TESTING

OPEN HOLE TESTINGwith RFT/MDT

CASED HOLE TESTINGwith DST

DG Propose/selects the testing/perforation sand, interval and depth

Estimate the reservoir fluid contents and its static pressure

Provide the reservoir rock parameter for testing analysis such as l ithology, porosity

and permeabil ity i f any (from log, or qualitative)

Stop the testing when unsafe operation Testing Engineer (TE) decision

Decide testing duration TE decide flow & shut-in periods. TE also

selects choke size for flow testing.

Select taken fluid sample TE decide fluid sampling methods. And

responsible for fluid sample handling

As Operation Witness will validate &

analyse the result

TE is prime Operation Witness and wil l

validate & analyse the testing result.

DG & TE will be along selecting the

perforation method

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PERFORATION1. THROUGH CASING GUN

Hyperjet/HSD(high shot density)

2. THROUGH TUBING GUN Enerjet

3. TCP (Tubing Conveyed Perforation)

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GUN TYPES

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DG and/or Wellsite eologist Responsibilitiesn Perforation Job

1. Define the perforation intervals at

porous zone & hydrocarbon zone(pay zone.

2. Evaluate and prepare the perforationdesign such as gun type, size, SPF

(shot per ft), Spacing (angle betweentwo shots), charge/explosive type;penetration deep and entrance hole.

3. Perforation environment (fluid typein the hole); using mud or brinewater or special completion fluid,under/over balance.

4. Witness the gun loading, correlation,shooting result (whether all chargesexploded or not) SAFETY FIRST

PERF. At Net pay

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