Technical- Part 3

Question 1

Why Vertical well or Horizontal well?

Answer 1

Verical- High permiability,

Horizontal low permiability, more stages.

Question 2

What is CFD and what are the paramenters in it?

Answer 2

Dimensionless Fracture Conductivity

• kf- frac perm
• w- width
• xf-frac half length
• k-formation perm

CDF = kf*w/k*xf

When FCD aproached 30, infinite conductivity

Question 3

Types of leakoff

Answer 3

Cw- wall building coefficient (linear gel)

Cv- viscosity control coefficient (filtate fluid flow)

Cc- Compressibility coefficient (reservoir fluid flow)

Spurt- initial leak off before the filiter cafke is formed

Question 4

What is leak off

Answer 4

Ct= Cw+Cv+Cc

Sum of all leak off tyepes.

Leak off help us to desing and make better our fluid efficiency.

How much fluid we are losing while we are injecting.

Question 5

Types of post job evaluation

Answer 5

Datafrac, Pressure matching, production history match.

Question 6

What is tortuosity?

Answer 6

pressure loss by fracture fluid between the perforations, and main fracture

Question 7

How does encapsulated breaker works

Answer 7

Pressure breaks the protein seal, needs to be tested with HPHT at the lab.

Question 8

1. How do you achieve higher frac conductivity during a HiWAY job? Which of these help?

Answer 8

1. Higher bottom hole flowing pressure
2. Less pressure across the fracture
3. Flow through a channel system rather than a proppant pack

Question 9

1. Understand Frac Modeling: Horizontal –

Answer 9

Horizontal – overburden is less than in-situ stress causing horizontal growth. Primary model when depth is less than 2000 ft.

Question 10

1. Understand Frac Modeling:KGD –

Answer 10

1. KGD – fracture length remains constant. It is a 2D model. The fracture half length is much less than the height. Used in thick zones. xl<h></h>

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Question 11

1. Understand Frac Modeling:PKN –

Answer 11

1. PKN – fracture height remains constant. It is a 2D model. Net pressure varies along the height resulting in elliptical width. The frac half length is much longer than the height. Used for thin zones. Xl>h by 3 times

Question 12

1. Understand Frac Modeling: RAD –

Answer 12

RAD – 2D model where the frac half length is almost equal to the half of the height.

Question 13

1. Understand Frac Modeling: P3D

Answer 13

1. P3D – Pseudo 3D model. Utilized when properties of all zones are consider. Width varies with fracture height.

Question 14

1. Understand Frac Modeling:PL3D –

Answer 14

1. PL3D – fluid flow in 2 directions. Height is calculated. Pressure drop is not constant. Long execution time.

Question 15

1. Understand Frac Modeling:MLF

Answer 15

1. MLF – model used to simulate multilayer fractures.

Question 16

2D Model Assumptions:

Answer 16

1. E, η, C_L and toughness are constant
2. Fluid flow in one direction
3. pressure drop in one direction
4. Lateral strain effects are small compared to the effects in the main body