Motivation Production data analysis software for shale gas/oil - PDF document

SPADES: Swift Production Data Analysis and Diagnostics Engine for Shale Reservoirs Xu Xue April 28, 2017 Motivation Production data analysis software for shale gas/oil reservoirs • Model free analysis of production data • Better insight of flow mechanisms • Characterization of fracture geometry and conductivity • Refracturing candidate selection 2

Outline • Motivation/Background • Methodology  Derive drainage volume, instantaneous recovery ratio (I.R.R.) and w( � ) from production data  w( � ) illustration for single infinite conductivity fracture  Refracturing candidate selection criteria • Demonstration 3 Radius of Investigation • Radius of Investigation is the propagation distance of the ‘peak’ pressure disturbance for an impulse source or sink (Lee, 1982) 4 kt  r  c Formation Linear Flow Fracture Interference t Wave Front Propagation 4

Generalization via Diffusive Time of Flight ( � ) Homogeneous Heterogeneous Radius of investigation Diffusive time of flight (Lee 1982) (Datta-Gupta 2011) Log10 Time (day) 2.5 2.5 2 2 2 2 2 2 1.5 1.5 1 1 1 1 0.5 0.5 0 0 0 0 0 0 r � 4αt α�x�|�τ�x�|�1 � Diffusivity � � Eikonal Equation ��� � Analytical 6 5 Drainage Volume and � ( � ) • ���� indicates how fast � � ��� • Visualization of the drainage w�τ� � �� � ��� volume evolution � � ��� increases �� (drainage surface area) 7

Outline • Motivation/Background • Methodology  Derive drainage volume, instantaneous recovery ratio (I.R.R.) and w( � ) from production data  w( � ) illustration for single infinite conductivity fracture  Refracturing candidate selection criteria • Demonstration 7 New Model-Free Methodology for Production Analysis • Drainage Volume (RNP Approximation) Generalization of MBH �Δ� �� � � 1 � (1954) PSS to � � � � � �� � � � � � � � �� � transient flow • Instantaneous Recovery Ratio IRR � � � � � � � Impact of Rate � � � � • Drainage Volume Geometry: w(  ) Flow Geometry � � � � � �� � � � �� � �� ⁄ � (Diffusivity Equation) 10

Analysis of Field Production Data • Given Pressure & Rate Data Pressure & Rate Data • Step 1: Drainage Volume 1 � �Δ� �� � � Drainage Volume � � � � � �� � � � � � � � �� � • Step 2: � ( � ) Function � ( � ) Function IRR Curve � � � � � ���� exp � � � � 4� � � • Step 3: Instantaneous Recovery Ratio (IRR) IRR � � � � � � � � � � � 11 Illustration: � ( � ) for Single Fracture Pillbox Shape Model Radial flow �� Linear flow • Drainage Volume � � � 4�� � � �� � �� � �� � � � �� � � � �� � � Finite boundary � 4 �� � � 2��� �� effect �� • Early Time: Fracture Area Linear flow � � � 4 �� � �� � � �� • Late Time: Permeability Radial flow � � � 2����� Linear flow Radial flow 12

Well Performance Analysis: Eagle Ford • 4 Eagle Ford shale oil wells are analyzed 11 Methodology: Drainage Volume and IRR • Well drainage volume • Drainage volume is calculated directly from pressure and production rate • The reservoir volume accessed by the well after hydraulic fracturing - Depends on the fracture geometry, fracture and reservoir properties - Independent of rate history • Well depletion rate • Define Instantaneous Recovery Ratio (IRR) as the ratio of produced volume to the drainage volume • How effectively the accessed volume is being produced - Depends on rate history 12

Methodology: Candidate Selection Criteria • Drainage volume looks at how Good Wells Good much pore volume is accessed by Small Reservoir the well Drainage Volume • IRR compares how efficiently the accessed pore volume is drained We qualitatively rank wells according to their drainage volume (per lateral length) and IRR after sufficient production time Poor Wells Poor Low IRR Reservoir 13 Ranking of Refracturing Candidate Large surface area Small surface area but low conductivity (region I) but high conductivity (region II) • Region I wells are more favorable for refracturing than region II wells • More practical to enhance fracture conductivity with region I wells • Challenging to increase stimulated reservoir volume with region II wells 14

Outline • Motivation/Background • Methodology  Derive drainage volume, instantaneous recovery ratio (I.R.R.) and w( � ) from production data  w( � ) illustration for single infinite conductivity fracture  Refracturing candidate selection criteria • Demonstration 15 SPADES: Introduction 16

SPADES: Production Data Import 17 SPADES: BHP Calculation 18

SPADES: BHP Regression 2 1 19 SPADES: Production Rate Regression 20

SPADES: Single Well Analysis 21 SPADES: Refracturing Candidate Selection 22