DrillingDrilling MethodsMethods UsedUsed byby thethe WesternWestern RegionRegion ResearchResearch DrillingDrilling ProgramProgram Wireline Coring Air Drilling Mud Drilling Logging and Construction Monitoring
Three-dimensional geohydrologic and geochemical framework analyses require reliable subsurface data. This includes collecting Geologic, Geophysical, Hydrologic, and Geochemical data. The Western Region Research Drilling Program (WRRDP) collects these data in all types of geologic environments using multiple drilling methods, geophysical logging of holes, and installation of wells and other instruments.
Steven Crawford U.S. Geological Survey Western Region Henderson, Nevada Wireline Coring
Wireline coring is the most efficient method for collecting cores. Cores collected using this method greatly enhance Coring sample 205 feet subsurface data. Using the Scale: In feet below land wireline system, cores can be surface taken continuously, or the drill-ahead system can be used if cores are taken intermittently. The WRRDP drill rig is capable of continuous coring a hole, then switching over to traditional drill pipe to ream the hole for instrumentation. 206 feet Western Region Research Scale in Drilling Program drill rig centimeters
207 feet
Latching up to 5-foot barrel attached to Hoisting core barrel up Core barrel being core barrel 5-foot spring retract to line up over tripped down hole wireline casing Note: Spring retract allows core barrel to protrude beyond cutting bit in soft zones. This protects the core from mud or air invasion.
Core barrel retrieved Barrel broken down Liner with core removed from barrel
208 feet
Proper handling and recording of core is critical prior to lab analysis. 209 feet
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Liner is cut and 210 feet Extraction of liner containing core is described core material Air Drilling
Air-hammer drilling is used in hard rock and unconsolidated-unsaturated studies. Unsaturated studies use an air-hammer/under-reamer system that pulls casing down as the hole is drilled. This allows wells and instrumentation to be installed inside the casing before the casing is pulled out of the hole. Reverse air circulation is also a method offered Drilling site using air-hammer drilling method by the WRRDP.
Air hammer
8-inch threaded casing (6-inch is also available for use with this system) Guide device
Under reamer Casing jacks and pilot bit "push" casing back out of hole with 50,000 pounds of force.
Air
Cyclone
Cuttings
Foot interval samples show dramatic changes on small scale. Air swivel diverter directs cuttings to The rig's 900 cfm/350 psi air compressor forces the cyclone cuttings to the surface through the diverter to the cyclone. The cyclone allows air to escape upwards while cuttings drop out through the bottom. For larger diameter holes, a backup unit can be piggy backed to the rig's compressor for additional air volume.
Simple onsite measurements plotting chloride profile
Cores can be immediately sealed airtight. Chemical and physical properties of the core material can then be analyzed in the lab. Cores in saturated and unsaturated Measuring EC and Cl zones can be taken using the push-core barrel. Two-foot cores can be analyzed for both physical and chemical properties. Mud Drilling
Fluid path Fluid path Both Direct and Reverse mud circulation methods are offered by the WRRDP. Direct mud circulation allows the scientist to collect both sieve and shaker samples. Spot coring is also possible. This method allows for rapid drilling of larger diameter holes and reaming of pilot holes. Flooded Reverse circulation uses either mud or water + polymers and air. Samples obtained using this method are very clean and accurate.
Drill pipe or collar
Stabilizer
Drill bit
Stabilizer
Drill bit Reverse circulation dual wall pipe
Reliable grout seals are set using a high-pressure positive displacement piston grouter.
The pickup pump "vacuums" mud and cuttings from the borehole and diverts them to the shaker or mud-filtering system.
The shaker tank serves as the mud filtration system. Once filtered the mud is then pumped back down the borehole.
The desilter cones or desander The shaker screen separates separate the finer sands from drilling mud from coarser cuttings. drilling mud.
Mud pumps
Dual positive displacement (piston) mud pumps force the drilling fluid down the borehole when the rig's centrifugal pump is over pressured. These pumps are used at deeper depths.
Typical cuttings collected by sieving mud and/or sampling from the shaker screen and cones. Logging and Construction
Borehole Geophysical Logging Well Construction
Geophysical logging services are included in all holes Well construction and instrumentation is performed by the the WRRDP drills. Logs are printed onsite and digital files WRRDP. For ground-water studies, typical construction well can be e-mailed to project managers. Standard logging nests include five to six individual monitoring wells. The tools which accompany the van include the following: screened interval of each well is surrounded by a sand resistivity tool (16-inch, 64-inch, lateral gamma, SP, temp., pack. Seals are pressure grouted into place between fluid resistivity), electromagnetic induction tool screened zones. (conductivity, gamma, in open or fluid-filled hole), caliper tool, and deviation tool or inclinometer. Special tools can Well also be also run such as the acoustic televiewer, sonic construction Lithology (density), spectral gamma, and the borehole camera. 5 4 321 6 0 Fill Silty sand
Electro- Silty muddy sand Magnetic Spontaneous Induction Potential Resistivity Resistivity (Conductivity) Silty sand Caliper, Gamma, SP, 16-inch, 64-inch, EM, Vs and Vp in in counts in in ohms in ohms in millimhos velocity, in Silty sand with inches per second millivolts per meter per meter per meter feet per sec coarse beds 0 10 20 0 100 200 -50 100 250 0 75 150 0 75 150 0 200 400 0 5,000 10,000 0 300 Silty sand
Sand 300
Silty sand
600
600 SAND
Sand
900 Sandy silt
GROUT Bedded silt with sand DEPTH FROM LAND SURFACE, IN FEET DEPTH FROM LAND SURFACE, layers Depth from Land Surface, in Feet 900 1,200
SAND Sand
1,500
GROUT Silty sand Geophysical logs and lithologic information Well site 4S/12W-25G 1-6 (Long Beach water 1) 1,200 Sand
SAND Coarse sand EM induction Bedded silt Resistivity with sand Caliper layers Deviation SAND Sand Coarse sand 1,500 SCREENED GROUT INTERVAL
Printer Computer Installation of unstaturated zone study instrumentation, such as neutron logging access tubes, gas-sampling tubes, psychrometers, temperature probes, and lysimeters, are Geophysical tools used standard procedure for the WRRDP. Seismometers and strain meters can also be installed for earthquake studies. Drawworks comes with 2500 feet of cable Well (piezometer) Inside of van showing computer used to covered by rag Instruments run logging and plotting software are wired to Heat dissipation data-logger probes
Instrumentation installed in borehole at Artificial Recharge Pond tracks downward migration of recharge through an unsaturated zone. Wires attached to two advanced tensiometers and seven heat dissipation probes Monitoring
The WRRDP has experience in monitoring Downward movement of wetting front at VVWD recharge pond along Oro Grande Wash near Victorville, southern California via geophysical logging. Two examples 0 below demonstrate the ability of 50 Position of wetting front Electromagnetic Induction logs (EM logs) Advanced tensiometers 100 Heat dissipation probes to track both fresh water recharge Electromagnetic logs 150 through the unsaturated zone in a desert 200 environment and seawater intrusion in coastal environments. Temperature and Depth, in feet 250 flow metering are other very useful logs 300 350 downward rate of that can be run repeatedly over time. movement ~ 0.27ft/d
400 O-02 D-02 M-03 J-03 S-03 D-03 M-04 J-04 S-04 D-04 M-05 J-05 Date
From J.A. Izbicki San Diego Ca. EM data are proven with data from instruments installed in the borehole.
Changes in EM logs over time show the downward movement of the wetting front
EM Logs for EM Logs for Well CM2 Well Q2
CM2 EM Log Change Q2 EM Log Change 1994 & 1996 (1994 – 1996) Feet 1994 & 1996 (1994 – 1996) Feet 0 mS/m 800 -800 mS/m 800 0 mS/m 600 -600 mS/m 600
100 100
The EM log conductivity 200 200 decreased in well CM2 at 150 to 240 feet below land surface, indicating 300 300 a retreat of the seawater front.
A comparison of EM logs done in 1994 400 400 (red) and 1996 (blue) shows the changes The EM log conduc- that occurred during the 2-year period. tivity increased in well Q2 at 500 500 800 to 850 feet below land surface, reflecting continued 600 600 water-quality degradation in the 700 lower aquifer system 700 in this area. 0 mS/m 800 -800 mS/m 800 CM2 EM Log Change Feet 800 1994 & 1996 (1994 – 1996)
900 For more information on this USGS program contact: Steven Crawford (702) 564-4541 or : [email protected] 0 mS/m 600 -600 mS/m 600 e-mail Q2 EM Log Change Feet 1994 & 1996 (1994 – 1996)