Modelling Unconventional Wells with Resolve and Reveal Juan Biörklund (Gauloise Energía) and Georg Ziegler (Wintershall Holding)

Modelling Unconventional Wells

with Resolve and Reveal

Juan Biörklund (Gauloise Energía)

and

Georg Ziegler (Wintershall Holding)


PVT Modelling

Reservoir Modelling

Well Modelling

Chemical EOR

Water Chemistry

Reveal Features

Adsorption

Diffusion

Rock Mechanics

Rock Failure

Fracturing

Designed to study specialized near well bore effects and assess their impact on the production from the reservoir


Quick Calculations

Tight reservoirs with complex well geometries

Systems with up to 20,000 wells with 100 wells being drilled per month

Shale Oil / Gas Wells

Horizontal, inclined and fractured wells

Gas adsorption, diffusion, directional stress dependent permeability variations etc...

Capabilities (Resolve & Reveal)


Dimensionless transient reservoir response capturing the well, fracture and reservoir geometry Dimensionless pseudo-pressure pseudo-time (pD tD)

Match this response to production history Modify reference parameters k and phi(rw

2)

Adjust PVT reference conditions for pD and tD

Concept


Perform predictions Use matched pD tD and super-position to predict Pwf

Transient IPR for rate estimation

Well scheduling

Automate the procedures using visual workflows Model definition and workflow in Resolve

Indirectly access simulation capabilities of Reveal

Concept (cont.)


6

Shale Gas Well


7

Microseismic

Frac Xf is 3 -5 x longer than seen in FracPro, proved with Microseismic

Multi-Fracs does not interfear near wells (approx. 300m)(Sketch not same as seen)


Fracture Input Parameters

8


Fracture Finite Element Grid

9


History Match

10

History match a shale well- Additional Input Data -

Young’s modulus (248000 bar).

Poisson’s ratio (0.275).

Biot’s coefficient (0.75).

Langmuir adsorption curve (70 scc/g).

Fracture permeability variation (no data).

Compaction table (Palmer & Mansoori – SPE 52607).

Fracture geometry and properties (NRT Log & Gohfer)


History Match

11

History matching : Reveal model


Input Parameters


History Match: Reveal Model

13

Calculated Pressure

Me

asu

red

Pre

ssu

re

Ra

te


pD tD Curves - Resolve

14

pD tD curves

Why

A method that allows us to perform rapid calculations with complex well geometries

What they are

Dimensionless transient reservoir response that captures the well, fracture and reservoir geometry



15

pD tD curves (pseudo-pressure pseudo-time)

02103266.6 3

P

pD B

dp

Q

khp

t

TwD c

dt

r

kt

02

3102637.024



16

Optimization

Resolve - Powerful Optimizing Tool on Field Level Production

Why Resolve

Handles large number of wells

Easy to analyze well performance

Infinite scenarios to find best match


pD tD Curves

17

Use GAP with Eclipse / Reveal / pD tD

One wellReveal Model

One wellpd td curve

Two wellEclipse Model


Resolve: Modelled vs. History


19

Shale Oil Well


Issues No gas break-through seen in the simulation

What is the frac geometry causing this behaviour?

Tight Reservoir Module uses only analytical method (pD tD)

3 Fracs simulated as one, inflow problems

Solutions Model the fracs explicitly with Reveal frac gridding option

Evaluate resulting pD tD curves from analytical vs. numerical

Detailed Resolve model explains where GOR increase when pressure is below Pb at certain fracs

Oil Models: Resolve & Reveal


Resolve pD tD Match

Dimensionless parameters – no geometry info


Resolve Workflow


Setup Resolve model and ran several cases to test sensitivity on different parameters and interaction between them such as:

Porosity, Stimulated K, Matrix K

Fracture half length, Fracture height

Stimulated Rock Volume (SRV)

Compressibility

Control Reveal with Resolve

RESOLVE Logic


Resolve / Reveal Sensitivities

24

Case_Name Porosity Permeability Compressibility Fracture Half Length Fracture Height SRV MatrixKCase_24 0.04 0.0008 1.00E-05 262 82 13 0.0001Case_25 0.04 0.0008 1.00E-05 262 82 13 0.0002Case_26 0.04 0.0008 1.00E-05 262 82 13 0.0003Case_27 0.04 0.0008 1.00E-05 262 82 13 0.0005


What is different between a Resolve analytical and a

Reveal numerical model?

Transfer fracture model from Resolve tight module to

Reveal to back calculate geometry.

Oil Reservoir Model


Pressure after one month

Reveal Oil Reservoir ModelModel variable compaction table, stress dependent

perm and changing cleat compressibility


Porosity Reduction with Pressure

27/11/2013 02/03/2014 30/06/2014

Effect of Cleat Compressibility

4.01

3.96

3.90

3.65

3.80

3.74


Reduction of Oil Density over Time

12/12/2013 31/01/2014 30/06/2014

Changing Oil Density over Time

41.5

40.4

39.3

38.2

37.1

36.0


Porosity and compressibility have similar effects on BHP match

Changes on SRV affects the late match

Stress - Permeability function has an effect on the transient behaviour (early decline / build up)

BHP calculation need careful considerations due to the instability of low rate wells.

Stress dependent permeability needs to be included in the Reveal models to obtain a match

Reservoir Model - Conclusions


30

Thank you for your attention

Questions?

Documents

Modelling Unconventional Wells with Resolve and Reveal Juan Biörklund (Gauloise Energía) and Georg Ziegler (Wintershall Holding)