Production Logging Fundamentals Learning Objectives Production Logging Fundamentals By the end of this lesson, you will be able to: Demonstrate the principles and operation of the logging tools associated with flowmeter tools Demonstrate the principles and operation of the basic temperature logs Demonstrate the principles and operation of basic radioactive tracer logs Discuss the added value of running a downhole video log in addition to production logs Present the principles and operation of basic spinner flowmeter logs Present the principles and operation of the gradiomanometer log Illustrate the performance of cased hole logs in single phase flow Understand the interest of running multiple tools within a Production Combination Tool 1
Major Through-Tubing Cased Hole Production Tools This Section Casing Collar Locator Log Gamma Ray Log Caliper Noise Logs Temperature Logs Radioactive Tracer Logs Spinner Flowmeter Logs Pressure Logging Tool Gradiomanometer Logs Not Covered Pulsed Neutron (TDT) Logs Casing Collar Locator (CCL) Counting Pipe Collars is a Common Application Counting Pipe Collars is a fundamental need for depth correlation Top magnet High impedance amplifier & voltmeter Collar locator Sub. 2ft (.61 m) Bottom magnet Permission to publish by the Society of Petroleum Engineers of AIME. Copyright 1983 SPE-AIME. 2
Production Logging Fundamentals Casing Collar Locator (CCL) Counting Pipe Collars is a Common Application Counting Pipe Collars is a fundamental need for depth correlation Initially correlated in depth by using a specific open hole log (usually the Neutron-Density or Gamma Ray log) High impedance Subsequent cased hole runs can be correlated by using only amplifier & voltmeter the CCL The CCL is a short tool that is Top run magnet immediately below the cable head Requires an electrical feed through to communicate with the sensors of the remaining tools Collar locator Sub. 2ft (.61 m) Permission to publish by the Society of Petroleum Engineers of AIME. Copyright 1983 SPE-AIME. 9000' 9050' 9100' 6' Bottom magnet Typical Casing Collar Recorder CCL Log Collar Logs A B Depth Advantages (2743 m) A. Running in hole (2758 m) (2774 m) B. Pulling out of hole (1.8 m) Permission to publish by the Society of Petroleum Engineers of AIME. Copyright 1983 SPE-AIME. Robust and rugged instrument. Limitations 1. Flush joint casing joints may be difficult to detect. 2. Some non-magnetic Corrosion Resistant Alloy (CRA) materials will not provide collar indications. 3. Some pipe manufacturers provide very consistent pipe lengths, and thus no variation in casing pipe joint length. 4. Small diameter CCL s (centralized) may not detect collars in large diameter casing strings. Remember: Different reading due to cable stretch 3
Gamma Ray (GR) Tool Gamma Ray: correlation with open hole logs Continuously measures and records natural radioactivity in the formations adjacent to the wellbore using radioactive decay of: Potassium, uranium, and thorium elements Generally use a scintillator crystal and photomultiplier receiver for maximum log quality Log reflects the shale content of rocks, as radioactive elements tend to concentrate in clays and shales Clean formations usually have low radioactivity Gamma Ray (GR) Tool Drill Collar Gamma Ray Detectors At least one GR tool will be run during the open hole logging program Subsequent cased hole GR logs can be correlated to this log The GR sonde detector measures gamma radiation Dual Detectors Bank A Bank B 4
Production Logging Fundamentals Gamma Ray (GR) Tool Main applications Gamma Ray: correlation with open hole logs Depth control measures for cased hole wireline natural operations Continuously and records radioactivity in the formationsdepth adjacent to the wellbore using radioactive decay of: Precision correlation Drill Collar Potassium, uranium, and thorium elements When radioactive sources have been introduced at a particular casing depth or by perforating charge H T least Sometimes At one GR tool will tool is used with perforating guns Generally use aa Gun-GR scintillator be run during the open crystal and photomultiplier Advantages hole logging program receiver for maximum Gamma Ray Simple tool requiringlog minimal interpretation Detectors quality Subsequent cased hole Limitations logs can be Log GR reflects the shale correlated to this log GR definition or variation may be low over intervals of interest, content of rocks, as making correlation difficult The GR sonde detector radioactive elements tend Can be the result of poor natural variations of gamma ray strength measures gamma to concentrate in clays Signal suppression due to sensing multiple through strings radiation and shales Centralized small diameter tool inside a large casing Bank B O PY Bank A R IG Clean Dualformations usually Detectors have low radioactivity Caliper Monitors wellbore condition (open or cased hole) After a drilling phase, caliper data are integrated to determine the volume of the open hole C Caliper offers a qualitative indication of the condition of the wellbore and the degree to which the mud system has maintained hole stability Very useful with any Production Logging run The caliper measurement point corresponds exactly to the measurement point of the flowmeter impeller 5
Caliper Monitors wellbore condition (open or cased hole) Blades or multi-finger types Limitations Applications AfterMain a drilling phase, caliper data are integrated to determine Caliper tool: the volume of the open hole Variable Variable resistance Normal two or four arm calipers Correct the flowmeter readings 1.Caliper offers aresistor qualitative indication of the condition of the will only give general indications for diameter variations due to wellbore and the degree to which the mud system of corrosionhas and other more either heavily scaled tubulars or maintained stability sophisticated tools need to be differenceshole in open hole AB completions Very useful with any Production Loggingrun runto examine the corrosion issues further 3. Determine restrictions for future tubing or casing work (workover planning) R IG 4. The caliper data can be used independently for determining general internal corrosion, Caliper paraffin buildup, or mineral Moving arm caliper scaling H T Locate packer seats in open 2.The caliper measurement point corresponds exactly to the hole sections measurement point of the flowmeter impeller O PY arm Caliper Blades or multi-finger types AB Caliper tool: Variable resistance C Variable resistor Caliper arm Moving caliper arm 6
Production Logging Fundamentals Caliper Monitors wellbore condition (open or cased hole) Blades or multi-finger types Limitations Applications AfterMain a drilling phase, caliper data are integrated to determine Caliper tool: the volume of the open hole Variable Variable resistance Normal two or four arm calipers Correct the flowmeter readings 1.Caliper offers aresistor qualitative indication of the condition of the will only give general indications for diameter variations due to Multi-finger Calipers wellbore and the degree to which the mud system of corrosionhas and other more either heavily scaled tubulars or maintained hole stability Motorized Centralizers to ensure effective centering force sophisticated tools need to be differences in open hole AB H R IG 3. Determine restrictions for future Damage tubing or casing work (workover Scale planning) Paraffin deposits 4. The caliper data can be used independently for determining general internal corrosion, Caliper paraffin buildup, or mineral Moving arm caliper scaling T with Equipped rollers to prevent casing andexamine tubing damage run the corrosion completions Very useful anywith Production Logging runto issues further Locate packer seatslogging, in open caliper For cased hole thecorresponds caliper will give indications 2.The measurement point exactly to the about: hole sections Conditions inside the casing measurement point of the flowmeter impeller O PY arm Noise Log C Spectral Noise Logging (SNL) is an acoustic noise-measuring technique used in oil and gas wells for: Well integrity analysis Identification of production and injection intervals Hydrodynamic characterization of reservoirs 7
Noise Log Spectral Noise Logging (SNL) Records acoustic noise generated by fluid or gas flow Tool listens passively to downhole noise such as gas bubbling up through liquid in the wellbore Behind pipe, a channeling flow passes through tight spots, which cause higher velocities, sudden pressure reductions and significant flow turbulence The noise-logging tool listens for noise associated with the turbulence The tool includes piezoelectric crystal transducers which convert the oscillating pressure of wellbore sound to corresponding oscillating voltage The oscillating voltage is applied to a speaker at the surface, as well as each of four high-pass filters Each high-pass filter detects nothing below its filter range Log noise filters for 200, 600, 1000 & 2000 Hz Two-phase flow occurs at about 200 to 600 Hz High rate single phase flow occurs above 1000 Hz Sound is highly attenuated by gas Tool works best for low rate gas leaks Noise Spectrum Relative amplitude Two phase 200 Single phase 600 1,000 2,000 Differential Pressure Frequency, hz 8
Production Logging Fundamentals Noise Spectrum Relative amplitude 200 Frequency, hz 600 1,000 High noise amplitudes indicate locations where the flow Two path phase is submitted to turbulence2,000 The noise log has been used as an indicator of channeling behind pipe Flow through channel is indicated on a noise log by the presence of high amplitude noise at places where restrictions in the channel causes throttling of fluid Flow through a leak results in a pressure drop Single phase that generates detectable noise Noise Log Principle 200 HZ 600 1000 2000 Differential Pressure Millivolts 55.0 27.3 14.1 High Pass Filters 5.7 Piezoelectric Crystal Microphone 9
Noise Log Principle Piezoelectric Crystal Microphone 200 HZ Millivolts 55.0 Filter s output consists of positive excursions from neutral alternating with negative excursions 600 27.3 Amplitude is measured two ways 1000 14.1 1. Measure from peak of positive excursions to trough of following 2000 5.7 negative excursion Peak to peak amplitude High Pass Standard gain or Standard sensitivity recording Filters 2. Measure from the peak of a positive excursion to neutral Peak amplitude One-half standard gain recording Noise Log Principle 200 HZ Millivolts 55.0 Measurements Filter s output consists of positive excursions from neutral alternating with negative excursions Amplitude is measured two ways A single station measurement lasts 3 to 600 4 minutes 27.3 Relocating the tool requires 1 minute 1000 14.1 1. Thus, Measure the logging from peak rate of is positive approximately excursions 15 stations to trough per of hour, following and 2000 a 5.7 negative 4-hour logging excursion run accommodates 60 measurements 30 measurements Peak to peak amplitude are used for a course-measurement grid, with successive High Pass Standard measurements gain or Standard separated sensitivity by recording 1/30 th of the total survey Filters 2. interval Measure from the peak of a positive excursion to neutral The remaining Peak amplitude 30 measurements are used for detailing areas of interest One-half standard gain recording Piezoelectric Crystal Microphone 10
Production Logging Fundamentals Noise Log Interpretation Single Phase Leak Gas into Liquid Leak A Noise Level Peak Millivolts Noise Log Interpretation Single Phase Leak DEPTH DEPTH B Noise Level Peak to Peak Millivolts Gas into Liquid Leak 1. Sound reflects downward at interface 2. The tool sensor is built for coupling to liquid rather than gas A Noise Level Peak Millivolts B Noise Level Peak to Peak Millivolts 11
Noise Log Application: Internal Well Blowout A well was drilled through (762) two (762) gas A well zones was drilled through two gas Plugged and abandoned, and the zones wellhead cut at the sea floor Plugged and abandoned, and the Six months later wellhead cut at the sea floor An internal gas blowout reached the mudline, causing the sea to (914) (914) churn Six months later A relief well was drilled to kill the uncontrolled An internal zone gas blowout reached the mudline, causing the sea to churn (1067) (1067) A relief well was drilled to kill the uncontrolled zone Temperature Log (1219) (1372) (1219) (1372) Temperature log Simplest, most accurate, and most widely applicable production log Temperature gradient changes are caused by natural phenomena within the earth s crust, and fluid movement Two curves: Gradient curve temperature vs depth Differential curve derivative of temperature with depth Temperature logs will be run both with the well flowing and shut in Gas expansion cooling is about 1 F (0.5 o C) / 40 psi (276 kpa) High water flow heating is about 3 F (1.5 o C) / 1000 psi (6895 kpa) Qualitative data help derive where, not how much 12
Production Logging Fundamentals Temperature Log HRT = High Resolution Temperature CCL T Electronic cartridge H Bridge O PY R IG Temperaturesensitive resistor C Geothermal Gradient Variation Temperature in well depends on factors such as: Temperature of surrounding formations Wellbore flow conditions Heat transfer characteristics of completion Fluid movement near the wellbore The temperature distribution in the earth s crust is called the Geothermal Temperature Profile Geothermal Gradient Varies Due to Rock Properties Through Layers The temperature trend in the earth s crust increases with depth, leading to a geothermal temperature profile 13
Local Geothermal Gradient O PY R IG H The geothermal temperature profile varies significantly from area to area, and the slope of the geothermal temperature varies from formation to formation T In desert conditions, surface temperature may initially decrease, reach a neutral point, and then increase Example of Geothermal Gradient C Knowledge of the geothermal temperature profile is necessary for temperature log interpretation Record one baseline log within a well shut-in and stabilized, before production start-up The geothermal gradient is generally assumed to be constant when interpreting temperature logs in a given area COOKING LAKE 14
Production Logging Fundamentals Temperature Log Applications Detect changes in surrounding temperature Identify annulus cement top after cement hydration Detect cooling effects of expanding gas (Joule-Thomson effect) Confirm operation of gas lift valves Help evaluate fracture treatments Identify true reservoir temperature for other studies, such as PVT Identify flow behind pipe (qualitative indication only) Identify leaks in completion (packer, tubing, etc) Qualitative evaluation of fluid flow by comparing with geothermal and/or shut in gradients Limitations: Quantitative interval flow rates cannot be determined Time lapse techniques during successive shut-in passes effective for identifying relative volume of produced/injected fluids Temperature Log Temperature profiles can be used to indicate where fluids are entering the wellbore Geothermal gradient Flow without gas entry Flow with gas entry Asymptote 15
Logged Temperature Gradient TEMPERATURE INCREASE CEMENT TOP Logged Temperature Gradient Geothermal gradient logged after cementing a casing string to identify cement top while cement is curing (Exothermic setting reaction) Logged Geothermal Gradient to Identify Lost Circulation If an initial (base line) temperature log has been recorded (Run #1), Then, after a small fluid volume has been pumped into the well, Run #2 shows a gradient shift occurring above the lost circulation zone providing evidence of a leak from an old or corroded casing. Temperature Increase Lost circulation zone e.g., leak in old casing 16
Production Logging Fundamentals Temperature Log Example (3200) Initial Temperature Log Log illustrates estimated normal thermal gradient and increased sustained temperature (fluid flow upwards outside pipe) Interpretation: high temperature fluid flow behind casing from 13,850 ft (4,221 m) (3505) (24.5 cm) T (3658) (3810) H (3962) (4115) R IG Hot fluid flow behind casing from source here Apparently, cross flow to about 11,000 ft (3353 m) (4267) O PY (4328) Temperature and Noise Logs Temperature Logs Noise Logs Before & After Remedial Work Before After C (3200) (3505) (3383) (3383) (3414) (3414) (3444) (3444) (3475) (3475) (3505) (3505) (3536) (3536) (19.4 cm) (24.5 cm) (3658) (3566) (3566) (24.5 cm) (24.5 cm) (3597) (3597) (3627) (3627) (3810) (3962) (4115) (4267) (4328) (3658) (3658) (3688) (3688) (3719) (3719) (3749) (3749) (3780) (3780) (3810) (3810) Before Remedial Workover After Remedial Workover 17
Typical Water Injection Well Temperature Geothermal Gradient Shut-in H T Depth Injection O PY R IG Injection Zone C Water Injection Well Temperature Log (1509) (1514) (1522) (1524) This log illustrates The water injection temperature profile And, The shut-in (1 hr) temperature profile as the warmer formation increases the temperature of the shut-in column of injected cold water This log also indicates a possibility of channeling below the depth of the lowest perforations (1530) (1555) 18
Production Logging Fundamentals Example of Thermal Anomaly Friction within rocks Gas expansion Channeling Well Temperature Log Production zones may or may not be clearly identified on a temperature log When free gas is flowing from the reservoir, pressure drawdown will induce a significant cooling of the gas in the nearwellbore vicinity due to Joule-Thomson effect Gas entry locations are identified by cool anomalies on a temperature log A B Gas C Ggrad DTS Prod-1 Rate Rate CumRate Gas or liquid? 19
Temperature Gradient Flowrate Interpretation Entry 3 Q 3 T G3 T L3 T 3 Entry 2 Q 2 Entry 1 Q 1 T G2 (Q 1 + Q 2 ) T L2 = Q 1 T 2 + Q 2 T G2 Q i = Q i-1 (T i -T Li ) / (T Li -T Gi ) T L2 For more information, review the Romero-Juarez Method which uses a similar gradient method Temperature Gradient Flowrate Interpretation Entry 3 Q 3 Entry T Li 2= the flowing fluid temperature at top of entry #i Q 2 T G3 Q i = the flowrate from entry #i T Gi = the static geothermal temperature at depth of entry #i T L3 T G2 T 3 T L2 T 2 T L1 T 2 (Q 1 + Q 2 ) T L2 = Q 1 T 2 + Q 2 T G2 Entry 1 Q 1 Q i = Q i-1 (T i -T Li ) / (T Li -T Gi ) For more information, review the Romero-Juarez Method which uses a similar gradient method T L1 20
Production Logging Fundamentals Temperature Logging Recommendations Record a full (top to bottom) reliable geothermal gradient log (base line log) during the first Production Logging run Routine: stabilize rate for 48 hours, log, shut in for about 24 hours Record temperature profiles, well shut-in, at repeated time intervals Log down and up, make re-runs (after 1-2 hrs), check log response Analyze temperature log versus flowmeter log Temperature profiles can be used for flow rate estimation Document results and recommendations Remember: in high rate gas wells, with low compressibility, the Joule-Thomson effect may be reversed and create a local heating at the fluid entry point (molecular friction effect) Radioactive Tracer Logs Mostly used on water injection wells Investigates only about 1 ft (0.31 m) deep outside casing Techniques: controlled time and interval Use peak-to-peak transit time Good for relatively low injection rates Typically use iodine I-131 (8 day half-life) Require precise well diagram Accurate logging of sequence of events essential 21
Radioactive Tracer Tool Shot = 20 cc CCL Ejector Port Top Gamma Detector Bottom Gamma Detector Radioactive Tracer Log: Tracer Loss Method Timed Logging Runs to Detect Radioactive Fluid Location Tracer Loss Measurement A Peak = slug position (1494) Signal amplitude proportional to flowrate B (1506) (1500) (1512) C (1518) D (1524) Run No. 1 4 min Run No. 2 6 min Run No. 3 8 min Run No. 4 10 min Run No. 5 12 min Run No. 6 14 min Run No. 7 16 min Run No. 8 18 min Run No. 9 20 min 22
Production Logging Fundamentals Radioactive Tracer Log: Velocity Shot Recorder on time drive detector stopped @ 4900' (1494 m) (1494) Ejector @ 4895' (1492 m) Start Time Reaction time in casing A = 10 sec (1497) (1500) (1503) (1506) (1509) (1512) (1515) (1518) (1521) (1524) Radioactive Tracer Guidelines Material clears tool in 33 sec Material channeling to 4900' (1494 m) outside casing Material being flushed into formation Caliper any open hole and run base log Log above injection zone, check flow rate Use two gamma ray detectors and centralize tool string Space to get reasonable tool detection times (> 10 sec) Use controlled times to find injection zones Use controlled interval to find flow rates Investigate all identified anomalies Document results 23
Continuous Flowmeter (CFM) Principle The Flowmeters spinner must flowmeter be centralized is the most in the commonly wellbore so used that accurate device for flow measuring velocity flow of flow profiles, stream both center in injection can be determined and production Use a caliper wells. for accurate flow Impeller determination placed in well to measure fluid velocity To determine Signal period the on minimum output coil fluid velocity required Frequency for spinner of rotation to rotate: F Measures in rps 1. Multiple up and down passes are made Characteristics and calibration chart is developed to rps determine are filtered fluid before flow velocity recording and cable Spin logging direction speedis now presented on logs Continuous 2. Spinner Flowmeter velocity will Sonde be at fluid (CFS) conditions Maximum at the point Pressure of measurement (psi) and will Maximum need to be Temperature converted back ( F) to stock 350 (177 tank C) conditions during final calculations Makeup Length (inches) 24.0 (61 cm) 15000 (103 mpa) Magnet Temperature and Flowmeter Logs Example 1 Temperature Log T A Electrical Connection Upper Bearing Pickup Coil Spinner Lower Bearing Continuous Flowmeter Depth T P M Depth Temperature G 1 C. T A Increased flow 24
Production Logging Fundamentals Temperature and Flowmeter Logs Example 2 Temperature Log T Continuous Flowmeter A2 M2 T1 P1 M1 Increased Flow O PY R IG Temperature H Depth A2 Depth P2 T T2 C Temperature and Flowmeter Logs Example 3 M Formation Producing Liquid at M Liquid Entering Casing at M Anomaly M Flow Behind Pipe M Formation Producing Liquid at M Liquid Entering Casing Through Perfs at M 25
Temperature and Flowmeter Logs Example 4 Anomaly M Expanding from Formation into Formation / Casing at M Gas Flowing from M with Little or No Expansion Gas Expanding from Annulus into Casing through Perforations at M O PY R IG Gas Expansion / Prod Rate at M Low Perm Rock Demonstrates More Cooling due to Greater Pressure Drop at Formation / Borehole interface H M T M Spinner Flowmeter Tools Types: continuous, full bore, diverter C Calibration in hole required Two-pass technique applied (log up and down) Use together with gradiomanometer (density differences) Slippage velocity and water holdup applied for calculation of two-phase flow rates Qoil and Qwater 26
Production Logging Fundamentals Full Bore Flowmeter Sonde (FBS) Early flowmeters were designed for low flowrates and adapted accordingly However, mechanical design involved flaws that sometimes induced operational complications These weaknesses led to the development of the Full Bore Flowmeter (FBS) tool Maximum Pressure (psi) 20000 (138 mpa) Maximum Temperature ( F) 392 (200 C) Weight (lbs) 11 (5 kg) Makeup Length (inches) 35.1 (89.2 cm) Courtesy of Schlumberger Full Bore Flowmeter Sonde (FBS) Early Uses collapsible flowmeters large were spinner designed blades for thatlow unfold flowrates only when and exiting adapted the tubing accordingly Run collapsed position within centralizer arms while within the tubing However, mechanical design Centralizer arms protect spinner blades involved flaws that sometimes induced However, operational both are easily complications damaged Both expand to large fraction of casing These inner diameter weaknesses by unfolding led to when the development reaching the larger of the casing Full Bore Flowmeter (FBS) tool Size of spinner blades allows larger flow cross section to be monitored Maximum Pressure (psi) 20000 (138 mpa) Maximum Temperature ( F) 392 (200 C) Weight (lbs) 11 (5 kg) Makeup Length (inches) 35.1 (89.2 cm) Courtesy of Schlumberger 27
Full Bore Flowmeter Sonde (FBS) Early Uses collapsible spinner blades flowmeters were The FBS large tool isdesigned more thatlow unfold only when the tubing for flowrates andexiting adapted complex than the Maximum Pressure (psi) Maximum Temperature ( F) Weight (lbs) Makeup Length (inches) O PY Courtesy of Schlumberger 20000 (138 mpa) 392 (200 C) 11 (5 kg) 35.1 (89.2 cm) R IG H reliable flow data as the Both expand to large fraction of casing These weaknesses led towhen the a inner diameter by unfolding spinner blades cover development of the Full Bore reaching the larger casing larger fraction Flowmeter (FBS)of toolthe whole Size of spinner blades allows larger flow topath. flow cross section be monitored T accordingly Run in collapsed position within centralizer arms while within the tubing continuous flowmeter but However, mechanical design Centralizer arms protect spinner blades tends provide more involvedto flaws that sometimes induced However, operational both are easily damaged complications Diverter Flowmeters The most accurate the spinner Maximum Pressure of (psi) 15000devices (103 mpa) low total rates and multiphase when Maximum Temperature ( F) 350 (177flow C) occurs. Weight (lbs) Makeup Length (in) cm) Can detect flowrates as low as60 10(152 to 15 Maximum to 2.4(bbl/d) m3/d). bbl/d (1.6Flow Spinner Hold-up Meter C Basket Open 2000 (318 m3/d) A typical 1-11/16-in (4.3 cm) tool has a barrel Basket Closed 10000 (1589.9 m3/d) ID of approximately 1.45 in (3.9 cm). Maximum Deviation ( ) 60 A flow of 10 bbl/d results in a velocity of 3.4 ft/min (1.04 m/min) inside the barrel. 3 Single phase (bbl/d) >100 (15.9 m /d) Because of the limited clearance between Qo in two phases (bbl/d) 30velocity (4.8 m3/d) the spinner and the barrel,>this is 3/d) Qw in two phases (bbl/d) >400 enough to overcome friction and (63.6 rotatemthe Accuracy (%) 10 spinner. A flow of 100 B/D passes through the barrel enough to start at 34 ft/min (10.4 m/min) Diverter/Basket Flowmeter the homogenization of the flow. Exit Ports Basket Size In a casing, a rate of Small Largem3/d) 2,000 bbl/d (318 Minimum Casing, in (cm) to obtain 4 ½the (11.4) 7 (17.8) is needed same effect around a continuous spinner. Maximum Casing, in (cm) 7 (17.8) 9 ⅝ (24.5) Metal Petals Water Resistivity Cell DC Motor The tool can be 1800 calibrated directly for such (286.2) 1000 (159) flow. Maximum Flow, bbl/d (m3/d) 28
Production Logging Fundamentals Diverter Flowmeters Basket Open Basket Closed Large 7 (17.8) R IG Small 4 ½ (11.4) 7 (17.8) 9 ⅝ (24.5) 1800 (286.2) 1000 (159) O PY Maximum Flow, bbl/d (m3/d) Metal Petals T >100 (15.9 m3/d) > 30 (4.8 m3/d) >400 (63.6 m3/d) 10 Diverter/Basket Flowmeter Basket Size Maximum Casing, in (cm) Hold-up Meter 60 Single phase (bbl/d) Qo in two phases (bbl/d) Qw in two phases (bbl/d) Accuracy (%) Minimum Casing, in (cm) Spinner 2000 (318 m3/d) 10000 (1589.9 m3/d) Maximum Deviation ( ) Exit Ports Maximum Pressure (psi) 15000 (103 mpa) Maximum Temperature ( F) 350 (177 C) Weight (lbs) Makeup Length (in) 60 (152 cm) Maximum Flow (bbl/d) H Water Resistivity Cell DC Motor Diverter Flowmeters The most accurate of the spinner devices Maximum Pressure (psi) 15000 (103 mpa) Small clearance between the spinner and low total rates and multiphase flow when Maximum Temperature ( F) 350 C) the ID of the barrel assures almost(177 no occurs. Weight (lbs) diversion of flow around the spinner. Makeup Length (in) cm) Can detect flowrates as low as60 10(152 to 15 As the it generates a Maximum (bbl/d) (1.6Flow to 2.4rotates, m3/d). bbl/dspinner Exit Ports Spinner Hold-up Meter C Basket Open of voltage pulses 2000 (318 m3/d) specific per Anumber typical 1-11/16-in (4.3 cm) tool has a barrel Basket Closed 10000 (1589.9 m3/d) revolution. ID of approximately 1.45 in (3.9 cm). Maximum Deviation ( ) 60 Apulse flow ofrate 10 bbl/d in acan velocity The fromresults the tool be of (1.04 m/min) the barrel. for 3.4 ft/minthrough transmitted theinside logging (15.9 m3/d) Single phase (bbl/d) >100cable Because of the limited clearance between surface recording and determination of Qo in two phases (bbl/d) > 30 (4.8 m3/d) the spinner and the barrel,per thissecond. velocity is corresponding revolutions 3/d) Qw in two phases (bbl/d) >400 (63.6 enough to overcome friction and rotatemthe Accuracy (%) flowmeters are rated 10 Typical basket for spinner. (160 177 C) temperatures 320 350 F A flow of 100 B/D passes through the and barrel 138 enough ft/min (10.4 (103 to mpa)to. start 15,000 at to34 20,000 psiam/min) Diverter/Basket Flowmeter Metal Petals Water Resistivity Cell the homogenization of the flow. 1.70-in (4.3 cm) tool accommodates Basket Size Small Large 3 In abbl/d casing, rate 3/d) of 2,000 bbl/d (318 m /d) 3,000 (477a m Minimum Casing, in (cm) to obtain 4 ½the (11.4) 7 (17.8) is needed same effect around 2.25-in (5.7 cm) tool: 5,000 bbl/d (795 m3/d) a continuous spinner. Maximum Casing, in (cm) 7 (17.8) 9 ⅝ (24.5) 3/d) 3-in (7.6 tool cm) tool: 8,000 bbl/ddirectly (1272 mfor The can be calibrated such Maximum Flow, bbl/d (m3/d) 1800 (286.2) 1000 (159) DC Motor flow. 29
Diverter Flowmeters The Measurements Small Maximum most clearance accurate Pressure are between of (psi) made the spinner with the 15000 spinner the devices (103 tool mpa) and when stationary. the Maximum ID low of the total Temperature barrel rates assures and ( F) multiphase almost 350 (177 no flow C) occurs. Weight (lbs) The diversion Makeup Can tool detect Length is of lowered flow around flowrates (in) to the the as low deepest spinner. as 60 10 (152 to 15 cm) measurement As Maximum the bbl/d spinner (1.6 Flow to 2.4 depth, rotates, (bbl/d) m 3 /d). then it generates opened. a specific Basket Open 2000 (318 m 3 /d) Basket A number typical Closed 1-11/16-in of voltage (4.3 cm) pulses 10000 tool has per After recording the measurement (1589.9 depth, a barrel m 3 /d) revolution. ID of approximately 1.45 in (3.9 cm). the Maximum tool is pulled Deviation up ( ) (while open) 60to the A flow of 10 bbl/d results in a velocity of next The measurement pulse rate from depth. the tool can be 3.4 ft/min (1.04 m/min) inside the barrel. Single transmitted phase (bbl/d) through the logging >100 cable for (15.9 m 3 /d) The Because of the limited clearance between Q o in surface risk of diverting two phases recording flowmeter (bbl/d) and determination getting > 30 of (4.8 m 3 /d) spinner and the barrel, this velocity is stuck corresponding Q w in two the enough phases hole is revolutions to overcome (bbl/d) higher than per friction >400 it second. would and (63.6 rotate mthe 3 /d) be Typical Accuracy for a spinner. basket continuous (%) flowmeters flowmeter. are rated 10 for 320 If the 350 F A flow tool of (160 is 100 stuck, 177 C) B/D the passes temperatures cable through can be the pulled and barrel 15,000 loose at Diverter/Basket to 34 and 20,000 ft/min retrieved. (10.4 psia m/min) (103 Flowmeter to 138 enough mpa). to start the homogenization of the flow. Basket If Size 1.70-in the flowmeter (4.3 cm) tool is stuck accommodates in casing, it may be In a casing, a rate of Small 2,000 bbl/d (318 Large 3,000 least bbl/d expensive to leave the tool in (477 m mthe 3 /d) Minimum Casing, is needed in (cm) to obtain 3 /d) hole. 4 ½ the (11.4) same effect 7 (17.8) around 2.25-in Maximum Casing, a continuous (5.7 cm) tool: in (cm) spinner. 5,000 bbl/d (795 m 3 /d) If the flowmeter is stuck 7 (17.8) in tubing, 9 ⅝ it (24.5) may 3-in The (7.6 tool cm) tool: can be 8,000 calibrated bbl/d directly (1272 mfor such Maximum Flow, bbl/d (m 3 /d) 1800 (286.2) 1000 3 /d) be necessary to pull the tubing. (159) flow. Spinner / Flowmeter Log Guidelines Need to achieve stabilized flow rate Calibrate tool Record multiple passes at various speeds Record stationary readings above and below perforations Record repeat runs The method is Best for single-phase flow Good for oil and water two-phase flow Questionable under liquids and gas flow Needs additional support (software, gauges, etc.) Questionable for hole angles beyond 70 Document all results Exit Ports Spinner Hold-up Meter Water Resistivity Cell DC Motor Metal Petals 30
Production Logging Fundamentals Pressure Logging Tool Usually contained within the same housing as the temperature tool Sensor (strain or quartz gauge) measures absolute pressure at logging point Its resolution is limited by a potentiometer transmitting device which causes pressure changes to appear as discrete steps on the recording Data to be used in combination with other production logging tool components Limitation: Quartz crystals need to be well protected or risk damage Gradiomanometer Measures pressure differentials Pressure differential is the sum of: Hydrostatic head Friction head The difference in kinetic effect between the 2 bellows Mechanism requires calibration with a known fluid At normal fluid velocities friction is very low, an unless there is a change in flow velocity between bellows, there is no kinetic effect Pressure differential as seen by the gradiomanometer is usually only due to the average fluid density Most effective for identifying gas entry and locating standing water levels 31
Gradiomanometer Components Spacing 2 ft (0.61 m) Electronic cartridge Transducer Upper Sensing bellows Slotted Housing Floating connecting tube Lower Sensing bellows Expansion bellows Gradiomanometer Components Spacing 2 ft (0.61 m) Electronic cartridge Readings to be corrected for hole deviation and possible friction Limitation: Application is of limited interest in highly deviated or horizontal wellbores when stratified flow is present Readings to be corrected for hole deviation and Hole deviation: Transducer Correction is applied possible by dividing friction reading by cosine of the deviation angle Limitation: Application is of limited interest in highly Kinetic effect: Upper Sensing Correction bellows to absolute deviated readings or is horizontal required due to high downhole flow velocity wellbores when stratified Slotted Housing Higher than 2000 bbl/d (318 m flow is present 3 /d) in 4-½" (11.4 cm) tubulars Higher Floating than connecting 5000 bbl/d tube (795 m 3 /d) in 5-½" (14 cm) tubulars Lower Sensing bellows Expansion bellows 32
Production Logging Fundamentals Gradiomanometer Log Interpretation Zones 0.4 gm/cc Free gas + liquid Gas or gas + liquid 0.7 gm/cc oil, or gas + water, or oil + gas + water T Hydrocarbon entry possibly with some water Water H 1.0 gm/cc water column either static or moving O PY R IG ρw = 1.0 gm/cc ρo = 0.7 gm/cc ρg = 0.2 gm/cc Production Combination Tool Great progress in production PCT Logging logging Tool has Specification been made with the development of tools to work under dynamic conditions Fullbore Flowmeter Combinations of tools Gradiomanometer C Caliper Flowrate meter Manometer Fluid identification devices Thermometer Depth control Casing Collar Locator Gamma Ray 33
Production Combination Tool (PCT) PCT Logging Tool Specification Fullbore Flowmeter Gradiomanometer Caliper Manometer Thermometer Casing Collar Locator Gamma Ray T In open hole, the presence of a caliper is essential. H In cased hole logs, it is useful to obtain a diagnosis on the actual casing diameter. R IG When local conditions are unknown, this PCT configuration helps to record the maximum amount of relevant data to diagnose well flow conditions. O PY Run only those tools that are needed ( Fit-forpurpose rather than Nice-to-have ). Flowmeter Quicklook Qualitative Analysis Depth Z m 0 GR GAPI 2000-40 CVEL m/ min 40-11 SPIN rps 15 6.6 CAL in 7. 0.95 W FDE g/ cc 1.04 113.4 W T EP C 114 2100 W PRE psia 2250 2310 2320 2330 C 2340 2350 2360 2370 2380 2390 2400 2410 2420 Fluid Entries Possible corrosion Fluid Entries Fluid Entries 2430 2440 34
Production Logging Fundamentals Conventional Production Logging Summary Essential recording tools for single- or two-phase flow: Thermometer (Temperature log) Spinner flowmeter Gradiomanometer Density log As a standard configuration downhole diagnosis tool, the Combination Logging Tool usually includes: Thru-Tubing Caliper Temperature log Spinner flowmeter Pressure log Gradiomanometer Density log Other logs include: The Noise log is useful in specific applications to diagnose flow issues The Radioactive tracer is used in injection wells The Thermal Decay Time log (Pulsed Neutron) is a reservoir engineering tool to monitor water saturations over well life All these tools provide valuable information to be analyzed by qualified analysts Downhole Video Alternative to Production Logs Advances in downhole video equipment now offer this measurement as an alternative to the new class of production logging measurements. A downhole video log is a means to directly identify location of fluid entries into the well, because almost all production wells contain water through which the hydrocarbons are passing. High rate water entries can also be detected from the image distortion caused by high levels of turbulence. This approach is qualitative and does not fully replace production logging tools. 35
Downhole Video Alternative to Production Logs Characterizing wellbore fluids Especially entry points Inspecting downhole mechanical equipment Downhole Video Alternative to Production Logs In Supplement open hole fishing wells, rock formations services are easily viewed Detect casing by the camera or tubing When leaks drilling mud is used, mud Spot is mineral opaque deposits and usually prohibits use of a video Find scale camera corrosion and bacterial buildup Examine the condition of downhole equipment Inspect the operation of downhole equipment 36