LEARNING OBJECTIVES PETROPHYSICAL DATA AND OPEN HOLE LOGGING BASICS MWD and LWD Acquisition By the end of this lesson, you will be able to: Understand the concept of Measurements While Drilling (MWD) and the difference between MWD and LWD Identify five or more typical MWD and LWD measurements, respectively Understand the terminology used for the different events and sections of a directional drilling well path Describe the downhole placement of the MWD and LWD sensors with respect to the bit 1
MWD and LWD Acquisition MWD AND LWD, THE KEYS TO HORIZONTAL DRILLING MWD Sensors include: Directional data Weight on the bit (WOB) Torque at the bit Pressure at the bit Applications and Advantages: Measurements While Drilling MWD (MWD) data include recording real time petrophysical data during Refers drilling to measurements and data used to optimize LWD is sometimes called formation the drilling evaluation process. while drilling (FEWD) Logging Real time While data is Drilling useful in (LWD) highly deviated and horizontal wellbores Refers to petrophysical log Measurements data that is recorded made early while in invasion process drilling. Real time ability to change It is an alternative to wellbore trajectories to reach target wireline logging. LWD Tools are run to acquire petrophysical data including: Gamma ray Resistivity Porosity Acoustic TOOL AND TECHNOLOGY DEVELOPMENT Logs specified in the evaluation MWD Tools 2
MWD & LWD TOOLS HAVE DIFFERENT USES Measurement While Drilling (MWD) Tools Uses: Wellbore steering Direction and azimuth Drilling parameters WOB, torque, pressure Correlation resistivity Gamma ray TYPICAL MWD MEASUREMENTS Logging While Drilling (LWD) Tools Uses: Real time logging of petrophysical parameters: Resistivity, Density, Neutron Porosity, Acoustic, NMR, Formation Imaging LWD density and gamma ray have azimuthal capability LWD can include resistivityat-bit (RAB) Torque Weight on Bit (WOB) Borehole pressure Borehole Temperature Tool Face Angle Hole Deviation from Vertical Hole Azimuth with respect to Geographic Coordinates Gamma Ray (GR) 3
MWD and LWD Acquisition DIRECTIONAL DRILLING AND LOGGING Kickoff Point (KOP) 2 nd Build Section Lateral Horizontal Departure MWD TOOL STRING True Vertical Depth Wireline logs are pulled down by gravity Wireline logs can be run in wells drilled with water based muds with hole angles up to about 45 to 50 Wells drilled with synthetic oil based muds (SOBM) run wireline logs in wells with hole angles up to 70 For higher angles, other log conveyance methods must be used Pipe conveyed logging uses special equipment 4
TOOL & TECHNOLOGY DEVELOPMENT Key Technology developments in Well Logging: Computer Processing 1960s Nuclear logging refinements 1970s NMR tools; established in the 60s but took several decades to refine First tool introduced by Numar (now Halliburton) LWD evolved from MWD measurements initially Gamma and Resistivity curve Now full suite of logs as for Wireline can be run on the pipe during the drilling process Key driver has been highly deviated and horizontal wells 80s Key advance was Mud Pulse Telemetry Early barrier was data transmission to surface LWD MEASUREMENTS AVAILABLE Resistivity shallow and deep Gamma ray Density Neutron Sonic Borehole imaging NMR (Nuclear Magnetic Resonance) Formation Pressure Fluid Sampler 5
MWD and LWD Acquisition DYNAMIC INVASION PROFILE CONCEPTUAL Drilling mud Invasion front DEEP READING PARALLEL TO BEDDING Wireline resistivity logs are typically run after significant exposure times to mud filtrate invasion May require invasion corrections LWD resistivity data is measured soon after drilling Typically does not require invasion corrections Major interpretation issue in shale gas, horizontal completions! 6
MWD LWD SUMMARY MWD: Real-time availability of drilling parameters LWD: Real-time availability of petrophysical parameters LWD: Resistivity, density, neutron, sonic and images comparable with wireline measurements LWD: Invasion-free formation resistivity at bit Petrophysical interpretation principles applicable regardless of the logging tool conveyance method LEARNING OBJECTIVES Advantages of LWD data over Example: Triple Combo Wireline data: LWD Tools = $25K per day Real time sonic and resistivity Log with wireline data can = be $500K used + 2 days rig time to predict increasing geopressures Deepwater well and takes alert 2 the drillers weeks to to drill increase and rig the rate mud = weight $1M per to day maintain safe drilling In this case, conditions. LWD logging is less expensive. Real time resistivity and porosity However, logs if drilling can improve on land selecting at 60 days the + $50K whole per coring day depth. rig time, then wireline logging is less expensive. Understand the concept of Measurements While Drilling (MWD) and the difference between MWD and LWD Identify five or more typical MWD and LWD measurements, respectively Understand the terminology used for the different events and sections of a directional drilling well path Describe the downhole placement of the MWD and LWD sensors with respect to the bit 7