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Software Requirements Techlog (v2021.1.2 recommended) Techlog Production Logging (v2020.2) PWP V1 Practical examples & project: Not released data! Delete data after class ends Basics of Production logging O&G Field Life Cycle Exploration...

Software Requirements Techlog (v2021.1.2 recommended) Techlog Production Logging (v2020.2) PWP V1 Practical examples & project: Not released data! Delete data after class ends Basics of Production logging O&G Field Life Cycle Exploration Appraisal Development Production Measure Diagnose Abandonment Act Production issues Production problems visible from surface High water cut High GOR Decline in the production Sand production and more…  Production Performance of a Well O il W a te r Region of Monitoring Region of Concern What is Production Logging? ? ? ? What type of production? Where is the production? How much production? Measurement of fluid parameters on zone by zone basis to yield information about the type and movement of fluids within and near wellbore Why do we run a Production Log? Leak detection Water shut off Flow Cross-flow contributions - Casing leaks - Plug setting - Obtain layer - Tubing leaks depletion information - Straddle packers - Reserves allocation - Gas lift valve leaks - Reservoir modelling Why do we run a Production Log? ? ? ? Well diagnostics often leads to intervention to remedy a production problem. The most common goal is the detection of water breakthrough, with a workover decision to be made. Production monitoring is often carried out on a periodic basis to quantify zonal contributions to the total well production. The information is used in reservoir simulation studies for production history matching and material- balance calculations. Injection monitoring is carried out to determine the amount of water or gas being taken by each layer in the reservoir. This is important for reservoir simulation. Well testing applications of PL provide both pressure and flow rate data during well tests. Terminology Holdup is the area fraction of the pipe occupied by the phase of interest. For oil-water flows: yw + yo = 1 For oil-water-gas flows: yw + yo + yg = 1 Vw Vo Vw Vo= Vw+Vs Cut is ratio of flowrates. For instance in an oil-water flow, water cut is given by - yw A (1-yw)A WC (%) = qw/(qo + qw) and more generally by: WC (%) = qw/qt Water Oil Superficial velocity is the velocity that a phase would have if it alone flowed in the pipe, i.e. Q/A. The sum of the superficial velocities is equal to the mean velocity: Vsh + Vsl = Vm A 12 Terminology Mixture Density is the density of a 2-Ø or 3-Ø fluid with a particular holdup combination of gas, oil and water and is given by: Vw Vo Vw Vo= Vw+Vs ρm = ρg x yg + ρo x yo + ρw x yw Slip velocity is the difference in the velocities between a lighter fluid and a heavier fluid, i.e. yw A (1-yw)A Oil slip velocity wrt water is given by: Vso = Vo - Vw Water Oil A 13 How do we perform Production Logging – Downhole Tools PBMS GHOST PGMS (Gradio) PFCS GR, CCL, Gas Holdup Density, Deviation Velocity, X-Y Caliper, Pressure, Water Holdup Temperature Slip correlations PVT yg + yo + yw = 1 --- Universal Relation Yg, Yw, ρ (T, P) ρm = ρg x yg + ρo x yo + ρw x yw --- Gradio Velocity, Area yw --- DEFT (PFCS) (Q = V x A) yg --- GHOST QT = Vm x A --- PFCS Qg, Qo, Qw = f (Holdup, Phase velocities, Area) A Typical Production Logging Tool PBMS (Production Basic Measurements Sonde) Gamma ray Casing Collar Locator (CCL) Pressure Temperature PGMC (Platform Gradiomanometer Carrier) Length ~10m Fluid density Deviation GHOST (Gas Holdup Optical Sensor Tool) 4 gas holdup probes PILS (Platform Inline Spinner) Inline spinner PFCS (Flow-Caliper Imaging Sonde) Fullbore spinner 4 water holdup probes X-Y caliper Pressure Use for pressure measurements in production logging: Pressure dropping while Well stability indication logging in a flowing well Calculation of PVT properties Reservoir and flowing pressures Fluid density calculations First down pass Last up pass Pressure Use for pressure measurements in production logging:  Well stability indication  Calculation of PVT properties  Reservoir and flowing pressures  Fluid density calculations DPDZc = pressure derivative wrt depth, corrected for deviation. WFDE = gradiomanometer fluid density, corrected for deviation Temperature Uses for temperature measurements in production logging: PVT properties Entry points are not clear on the Qualitative flow analysis in low flowrate spinner curves due to low fluid conditions velocity in a 9-5/8” casing. Leak detection Entry points can be identified using Quantitative flow analysis the temperature curves. Temperature Measurement Temperature Exchanges in a well 19 Typical Temperature Log 20 Well Producing Liquid Well Producing Gas Spinner Temperature Spinner Temperature geothermal geothermal gradient gradient gas flow Water Flow 21 Liquid Channeling Gas Channeling Spinner Temperature Spinner Temperature geothermal geothermal gradient gradient Water Flow Flow behind behind the casing casing 22  Crossflow 1 Temperature Th e temperature initially reacts to the fluid entry at the perforations. flowing Crossflow from zones 4 - 3, means colder fluid is flowing down. 4 The temperature reacts showing a Schlumberger Confidential Crossflow flow + drop from the point where the down crossflow stops. 3 Crossflow 2 Geothermal Gradient Geothermal 1 perforated zone  Crossflow 2 Temperature This is the same situation as the flowing previous case except the flow is now in the up direction A heating effect is seen on the 4 temperature. Schlumberger Confidential flow + Crossflow Crossflow up 3 2 Geothermal Gradient Geothermal 1 perforated zone Leak A leak may show a drop in flowing temperature as fluid is entering into the formation leaving less fluid in the borehole. leak flowing with leak Schlumberger Confidential zone Geothermal Gradient perforated zone Fluid Properties Surface Conditions Water Gas Oil  PVT of Water Water density and viscosity change only slightly with pressure and temperature Density is mainly affected by the proportion of dissolved salts (salinity) Density vs salinity at standard pressure and temperature PGMC: Differential pressure gradiomanometer Factors affecting the Gradio density measurement Friction – In liquid wells above 2.5 m/s, correction will be needed for the frictional pressure drop. Yo-Yo – A bouncing tool will superimpose a sinusoidal signal on the density. This will require careful filtering to remove it. Jetting entries – First one and then the second pressure port will see an elevated pressure from a jetting entry. Density data opposite a jetting entry cannot be interpreted. Acceleration – Where the flowing cross sectional area changes, the flow will accelerate/decelerate and the apparent density increase/decrease. No corrections are possible. Deviation effects (Loses accuracy after 60deg deviation). Spinners Fullbore spinner on PFCS Inline spinner (PILS) Flow Scanner (FSI) mini spinner PFCS : PSP Flowmeter Caliper Sonde Spinner selection Criteria PFCS: Fullbore spinner vs turbine Fullbore spinner Turbine 4 sizes (2.2”, 2-1/2”, 3-1/2”, 1 size 4-1/2”) Foldable Not foldable Low to medium fluid High to very high fluid velocities velocities Repairable Not repairable Can get you stuck Cannot get you stuck FSI Tool Spinner response Flowrate measurement relies on relative fluid to tool velocity The spinner measures the average velocity of all the fluids V Cable Velocity Spinner rotation is measured in RPS or C/S Fluid Velocity V Spinner rotation Calibration Fluid Velocity Production Logging Procedure Cable Speed Spinn - +- er + Production Logging Procedure Cable Speed Spinner - +- + Production Logging Procedure Cable Speed Spinner - +- + Production Logging Procedure Cable Speed Spinner - +- + Production Logging Procedure Cable Speed Spinner - +- + Production Logging Procedure Cable Speed Spinner - +- + Production Logging Procedure Cable Speed Spinner - +- + FLUID ENTRY Apparent velocity to Mixture velocity Spinner velocity, Vapp, comes from the green area and therefore the mixture velocity, Vm, is smaller Vm = Vapp x VPCF VPCF is the velocity profile correction factor Practically VPCF varies between 0.6 to 0.93 In the interpretation software, VPCF is determined using the Reynolds number and the ratio between spinner blade and pipe diameter Reynold’s Number Reynold’s Number is a dimensionless group: Schlumberger Confidential D v   N Re  7.742  10  3  where: D = Pipe Internal Diameter (in) v = Fluid Velocity (ft/s) r = Fluid Density (g/cm3) m = Fluid Viscosity (cp) Turbulence will not occur if Reynolds number is less than 2000 Usually the fluid is fully turbulent if Reynolds number is more than 4000 Velocity Profile Correction Factor In most cases, and for use in the field, a value of: C = 0.83 Schlumberger Confidential will give satisfactory results For computational use, a curve fit can be used using: m=log10(NRe) where m is defined and C computed from the table 0.000 < m < 3.200 C=0.5 3.200 < m < 3.348 C=1.0135m - 2.7432 3.348 < m < 3.554 C=0.4440m - 0.8360 3.554 < m < 3.850 C=0.1450m + 0.2390 3.850 < m < ∞ C=0.0400m + 0.6260 Velocity Profile Correction Factor ( Vavg = Vmax * C ) 1.0 0.9 Schlumberger Confidential 0.8 Transition Region Laminar 0.7 Flow Correction Turbulent Flow Factor, C 0.6 0.5 0.4 0.2 0.1 101 102 103 104 105 106 107 108 Reynolds Number, NRe  Conventions POSITIVE cable velocity is going down Consider that depth, Z, is assumed to be increasing with time as we go down, so dZ/dt is positive, the cable velocity is positive Positive spinner when tool is going down In zero flow conditions the spinner rps has the same sign as the cable velocity Calibration plot axes Positive Spinner Up Velocity Down Velocity Negative Spinner 9/15/2024  In Situ Spinner Calibration – Zero Flow 10 Spinner (rps) 8 Positive spinner slope 6 Typically we choose; 4 Negative Positive spinner intercept spinner threshold 3 +ve velocities and 2 RPS -100 -80 -60 -40 -20 0 0 20 40 60 80 100 3 –ve velocities Tool Velocity (ft/min) -2 Negative spinner slope Negative Positive But these can choices spinner threshold -4 spinner intercept can be adjusted. -6 d -8 -10 9/15/2024  Spinner Response Change in viscosity Spinner RPS Increasin g fluid viscosity Fluid Velocity Increasing fluid viscosity  Spinner Exercise 20 Pass Spinner Cable speed (rps) (ft/min) 1 8 50 15 3 10 100 Spinner rotation (rps) 5 12 150 2 2 -50 10 4 -2 -180 6 -4 -220 7 -6 -250 5 121 Construct flowmeter calibration 0 plot. -300 -200 -100 0 100 200 Determine the fluid velocity. -5 -10 Cable speed (ft/min) 9/15/2024  Spinner selection Criteria Maximum relative Maximum relative fluid velocity fluid velocity Spinner Blade (in) Casing (in) Slope (rps/fpm) Pitch (in/rev) Threshold (fpm) recommended for before spinner bearing life collapsing (ft/min) (ft/min) 2.2 4-5 0.100 1.97 N/A 980 N/A 2.5 4-5 0.089 2.24 6.55 1120 800 PFCS 3.5 7 to 9-5/8 0.96 2.08 4.98 1040 250 4.5 9-5/8 0.091 2.19 2.96 1090 100 fpm) Use a value from experience in other wells or Use the value from the spinner design (eg. 5 fpm) SLB-Private  Velocity Calculation Based on Flowing In-Situ Calibration(s) – Determine X-axis intercept for rate (i) or – Determine Y-axis intercept for rate (i), y(i) Vt from Zero- – Determine response slope, m(i) flow Velocity given by: y(i) calibration Vmax(i) = x(i) + Vt = + Vt m(i) Why are the response curves not parallel? – Different fluid type or mixture (holdup) – Increased efficiency of energy transfer to the spinner at higher speeds. SLB-Private  Flowing & Zero flow zones Spinner RPS Threshold of the “Positive” line - Vt + Vt Up Down Cable Speed 2 x Vt SLB-Private  Non-directional vs Directional Spinners Non - Directional Directional Spinner Increasing velocity Spinner rotates clockwise due to tool movement in static fluid Fluid entries No Flow 0 20 -10 0 10 SLB-Private  Non-directional vs Directional Spinners Non - Directional Directional Spinner Increasing velocity Spinner rotates clockwise slowly due to fluid entry Fluid entries No Flow 0 20 -10 0 10 SLB-Private  Non-directional vs Directional Spinners Non - Directional Directional Spinner Increasing velocity Spinner stalls when tool and fluid velocity are very close Fluid entries No Flow 0 20 -10 0 10 SLB-Private  Non-directional vs Directional Spinners Non - Directional Directional Spinner Increasing Spinner starts turning again velocity in other direction, as fluid velocity exceeds tool velocity Fluid entries No Flow 0 20 -10 0 10 SLB-Private  Basic Concepts and Definitions Holdup: the area fraction of the pipe occupied by the phase of interest Cut: the ratio of flow rates. E.g. water cut, WC (%) = Qw/Qt Superficial velocity: the velocity that a phase would have if it flowed alone in the pipe, i.e. Qi/A. Mean velocity: the sum of the superficial velocities, Vsh + Vsl = Vm Slip velocity: the absolute velocity difference between phases flowing together, Vs = Vl – Vh Single Phase Flow Rate = Average Velocity x Area Multi Phase Flow Rate = Phase Velocity x Phase Area -Phase Area = Area x Phase Holdup SLB-Private Holdup In two phase oil-water flow, buoyancy causes the oil bubbles to rise through the slowing moving water. Since the lighter phase is travelling faster, the heavier phase is said to be ‘held up’ in the pipe, hence the expression ‘hold-up’. Water holdup (FloView ) FloView probes differentiate water from hydrocarbon based on fluid conductivity FloView probe DEFT (Digital Entry and Fluid Imager Tool)  Provides holdup measurements for hydrocarbon-water system  Based on the electrical conductivity of the flowing fluid 62  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time  Holdup Measurement Non Conducting( Conducting Low volt) Conducting Conducting(High Volt) Time Specifications WATER Hold-Up Electrical Probes Accuracy 5 % (2% w hen Yw >90)m Devi 1mm Max imum fluid v elocity 2 m/s (telemetry) Minimum w ater salinity 1,000 ppm @ 100degC Limitations Water Continuous Phase, 2,000 ppm @ 25 degC …. Charts Mixture Velocity < 2m/s 1 Caliper LVDT Oil Continuous Phase, Range 2 to 11 in Mixture Velocity < 1m/s Accuracy / Resolution 0.2 in / 0.04 in Orientation Relative Bearing (min 10 deg dev.) Accuracy +/- 6 deg 84  Holdup Measurement Holdup is a downhole fraction measurement:  Only differentiates water vs hydrocarbons  Distinct fluids and Show entry points in two and three-phase flow  Local measurements are representative  Flow is not affected by presence of the sonde  Determine volumetric flow in two and three-phase flow Probe output is binary Water Holdup is computed as: Flow Probe Yw=signal low time/total time Time 0 1 Water Holdup ≠ Water Cut GHOST (Gas Holdup Optical Sensor Tool) Four Optical Probes Provide Gas Holdup and Bubble Count Minimum 0.1 mm bubble size can be detected 86 Gas Holdup Optical Sensor Tool (GHOST) Probes differentiate gas from liquid based on contrast in refractive index Probe Response 88 Cases for using the sensors Case Spinner Gradiomanometer Caliper, Temp. & FLOVIEW GHOST Press. Injection Y Optional Y Optional Single Phase Y Optional Y Optional Water-Oil Y Y Y Y Water-Gas Y Y Y Y Oil-Gas Y Y Y Y 3-Phase Y Y Y Y Y 9/15/2024  Multiphase flow - Effect of Deviation Oil velocity is high due to buoyancy Some water is displaced by the oil and moves down Segregation occurs quickly Main body of water moves upwards Oil entry Deviated Well-Recirculation Typical PL program Shut-In conditions Flowing conditions Perform passes at different speeds across the Wait for stable flow interval of interest Schlumberger Confidential – pressure, spinner, density ? Perform spinner calibration Log interval of interest (passes up and down at Determine fluid levels different speeds) – Perform spinner calibration Detect Cross-flows (if any) – Identify flowing profile & cross-flow – Identify fluid entries Log stations if requested Shut-In the well before POOH in the Tubing ! Production Logging Interpretation FACTS Single phase: determination of downhole profile and Schlumberger Confidential interpretation of downhole data is straight forward. Multiphase flow : phenomena like holdup, slippage velocity and phase segregation complicates the flow behavior. For the interpretation of production logs under multiphase flow conditions, Holdup is of major importance. Single Phase Interpretation Qo (bpd) Sensors used Flow meter Schlumberger Confidential – To calculate total flowrate Temperature – Fluid entries, Flow behind pipe Pressure – Well performance Multiphase Interpretation More Sensors required Gradiomanometer – Fluid mixture density Schlumberger Confidential eProbes: PFCS or DEFT – Water Hold-up oProbes: GHOST – Gas Hold-up Fluid Conversions: PVT Downhole rates to Surface ? INTRODUCTION TO PRODUCTION LOGGING IN Schlumberger Confidential HORIZONTAL WELLS  Gas Failed External Casing Packer Fault Formation Instability Schlumberger Confidential Stagnant Gas Fractures Cuttings Oil Layer Stagnant Water Water Effect of Deviation on Flow Ideal Horizontal Well – 90deg Schlumberger Confidential 90 degrees Effect of Deviation on Flow Horizontal Wells at 88 deg and 92 deg Schlumberger Confidential 88 degrees 92 degrees  Schlumberger Confidential Flow Scan Imager (FSI) FSI Applications Measure the phase holdups Measure the phase velocities Schlumberger Confidential Measure the diameter Compute flow rate Flow rate = holdups  velocity  cross-sectional area 1 mini-spinner, 1 FlowView & 1 GHOST probe The FloScan Imager Advantage over Conventional String Schlumberger Confidential Techlog Production logging Techlog Production Logging Workflow Depth-based Wellbore Spinner Fluid Properties PL data Image Plot Calibration Data export Setup Multi-pass Rate Data Stacking Parameters Display Calculation Time-based PL data Summary Report TPHL data Holdup Optional tools SIP Corrections WPA Data Preparation Visualization / QC Processing Answers Results Techlog PL – Data Preparation Wizard to complete the data preparation in few clicks. For customized preparation use the methods Sensor activation - Used to deactivate bad sensor data Station Preparation - Used to get stations ready to plot on the depth log Passes setup - Applies properties to variables and dataset & organizes the project browser for clarity Tool setup - Applies tool string related properties to the data & additional computation using default configuration Unit change - Rename unidentified unit to Techlog units Techlog PL – Data Preparation DLIS & LAS Techlog PL – Toolbox  Multipass Display – Plots chosen variables with the same scales and correct colors  Station to depth – Creates a depth based dataset from stations  Reference match – Used to automatically align multiple logs to the same reference depth  Variable Flag – Used to disallow sections of data from processing  Plots  Wellbore image plot - Creates images from data (commonly probes)  Section profile plots  Holdup & Flow profile plot Techlog PL – Processing & Stacking  Spinner Velocity  Interactive computation of slopes and thresholds  Compute Vapp with automatic algorithm  Holdup Processing  Used to disallow sections of data from processing  Holdup computation from capacitance and resistance  Multi-sensor processing  Computes position-dependent averages from inputs  Includes MapFlo & FSI processing for SLB tools  Stacking  Combine the results of many passes into one averaged dataset Techlog PL – Fluids, Rates, WPA, SIP and Report  Fluids  Defines the fluids that exist in each reservoir zone  Creates an (optional) output table for viewing  Rate Calculation  Input the stacked dataset, PVT & zonations  Computes the flow from each zone & surface equivalents  Selective inflow profile  Compute the reservoir pressure and AOFP  Well performance advisor  Helps choose the appropriate intervention  Summary Report  Using the built-in report editor in Techlog  Customizable to save you time Questions