a methodology for the refinement of well locations during operational drilling in presence of...

181992

A Methodology for the Refinement of Well Locations

During Operational Drilling in Presence of Geological

Uncertainty

V.M. Babin, A.M. Vashevnik, O.S. Ushmaev A.P. Gruzdev, A.V. Pozdneev, A.S. Semenikhin,

B. da Costa Flach, M. Paredes Quinones, D. Echeverría Ciaurri

LLC «Gazpromneft Science & Technology Centre»

Development System Selection

181992 A Methodology for the Refinement of Well Locations During Operational Drilling in Presence of Geological

Uncertainty

Babin V.M.

Definition of the following parameters:

• wells placement

• wells type

• wells control parameters

• drilling rate

Subject to target objective function(s) optimization, for example, NPV, Recovery

Factor and so on.

Simulation

Эффективность

Risks

Well pattern

Efficency


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Development System Selection

What should we do with reservoir characteristics update?

Depends from the stage of field development

• Early stages

Development concept update

• Production drilling

Development system adaptation

Slide 4


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Reservoir quality update during production drilling

1. We start to drill a new well pad

2. If reservoir quality will be far from the

expected we need to:

• promptly make a decision about

development system adaptation

• find a solution which maximize

reservoir potential

Slide 5


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Strategy of Technological Solutions Evaluation

IdeaCreate a strategy of local technical solutions of oilfield development in

advance (before production drilling)

Thereby:

• assess all options possible development scenarios

• define simple rules system: «if …, then drill …»

• suggest an uncertainties reduction program

Slide 6


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New well pad (horizontal wells, top view)

Option DS1 Option DS2 Option DS3

W1

W2

W3

W4

Potential development systems


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Technological tree example


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Navigation through technological tree


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1

23

3

4

W1

W2

W3

W4

1

3

3

2

4

4

Option DS1 Option DS2 Optino DS3

Chose a path with maximum

expected NPV

Chose a path with maximum

expected NPV

Calculation and usage of technological tree

ENPV – Expected value of NPV


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Real asset problem definition

Input data:• base case for development system:

horizontal wells 1000m with row

distance betwee 300m

• defined set of uncertainties

Goal:• NPV maximization

Approach:• Find an optimal strategy of local technological solutions for development

system adaptation

The structure of the reservoir: vertical slice across the axes

of horizontal wells


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Babin V.M.


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Real asset problem definition

Development system parameters variance:

• row distance

• production-injection wells ratio

Well pad – an area of 1200m length

• Standard approach require to decrease

number of considered uncertainties that

decrease potential expected NPV of the

project

• Need to justify some uncertainties

reduction program

Base case


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• Technological tree of

possible development

system solution automatic

generation for well pad

production drilling;

• Expected NPV value

increase at 15%* with the

same Recovery Factor

level

* In respect to pre-

defined base case

Slide 13

Methodology test at real asset


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1. New methodology proposed of development concept adaptation that

doesn’t require additional computation experiments during

production drilling;

2. The methodology allows to make dynamic decisions about well

placement on a basis of information received during production

drilling;

3. Methodology allows to justify uncertainties reduction program

Conclusion

Back-up slides


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Type of Uncertainties

The structure of the reservoir: vertical slice across the

axes of horizontal wells

The low degree of confidence in the local

properties:

• thickness

• absolute permeability

• aquifer activity

• different sedimentary regions

connectivity

• relative permeability


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Production Forecasting

Simplified hydrodynamic model of the well pattern (well pad)


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How to Make Decisions?1. Start to drill «base» well pattern #0

2. Form the operational well or its appraisal branch clarify local reservoir property

• if h1 < h < ht1 – less dense (*)

• if ht2 < h < h2 – more dense pattern (**)

1. High well density

2. low well density

0. “baseline” – average well density

Rules like (*) and (**) are calculated before

well pad drilling;

In the process of drilling all solutions are

dynamic, without recalculation

ht1

h

NPV

1

2

h1 ht2 h2

0


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