Milling operations are underway. We expect to start directional drilling of sidetrack 2 tomorrow. It will take several days to directionally drill the sidetrack before coring can begin.
Much has happened in the past week. Last Friday, a second attempt was being made to fish the stuck bottom-hole assembly. This attempt was unsuccessful, and the decision was made to terminate efforts to save this side track. The pipe was pulled out of the hole, and the milled window at 3,124m was cemented shut. Efforts then began for drilling of the second side track with a window at approximately 2,941m. To facilitate drilling, a top-drive system was substituted for the kelly drive. Now with the top-drive in place, the whipstock has just been placed into position. Milling of the window will begin shortly.
Our attempt to recover the stuck bottom-hole assembly from the top of core hole 1 last night was not sucessful, so we are now gearing up for our second fishing attempt. Assuming this operation is sucessful, then we have several days of rig operations and hole conditioning ahead of us before we can start coring. We will not be posting daily updates during this time, so that our hard working on-site core handling team can take some time off. We will be back ""on the air"" in a few days.
Operations continued today to free the pipe from the milled window. A free-point determination was successfully completed last night, and the joint above the stuck point was shot free. The pipe was tripped out this morning and a new bottom-hole assembly comprised of a watermelon mill, bumpers, and jars is currently being sent back down the hole to fish the stuck pipe.
After successfully retrieving the 5 inch casing, a reamer run was started to clean the open hole prior to coring. When the bit reached the measured depth of 3194 meters, which is the depth of one of the active faults that offset the casing in the main hole, we had considerable difficulties. When pullijng the drill string from the open hole, a stabilizer in the bottom hole assembly became stuck at the top of the window milled through the casing. Operations are underway to free the pipe.
After multiple attempts, the 5 inch casing used to support the DOSECC coring string would not reach the bottom of the open hole interval. It was decided to remove this casing and use a conventional core barrel with a downhole motor. In the photo, some of the 5 inch casing is shown being laid down by the crew in preparation for a reaming run.
Following reaming of the hole, efforts are underway to deploy the 5 inch casing to the bottom of the hole. This casing is used to support the coring rods.
Reaming of the hole went very well last night. Today the pipe was tripped out and the lower section was laid down. Tonight the 5"" bushing pipe will be placed in the hole in final preparation for coring.
Reaming of the hole commenced today in preparation for running in the 5 inch guide bushing (steel pipe that stabilizes the coring rods) before we rig up the top drive DOSECC coring equipment. The onsite core science team is finalizing preparations to handle, photograph, and log the core which should be on deck shortly.
The rotary drilled section for corehole 1 was successfully completed today. This hole parallels the main hole drilled in 2005 and is offset by approximately 10 meters. After tripping out, a reaming assembly will be run in the hole in preparation for installation of the 5 inch casing needed to support the coring system.
Directional drilling continues on our way to the first core run. Today was an unusually cloudy, cool day out at the drillsite: a much appreciated respite from the hot weather of the past couple of weeks.
Over the past day, we have directionally drilled several hundred feet. The pipe was then tripped out early this morning, and the hole was reamed until mid afternoon. A gyrocscopic survey was then made to confirm the drilling direciton. Following a successful survey, the night crew will resume directional drilling early next morning (July 10).
Directional drilling continued this morning. In order to keep the hole on track, the rig crew tripped out pipe and is preparing to ream the hole prior to sending the gyroscope down to the bottom.
Drilling is progressing rapidly following several days of slow timed drilling through arkosic sandstone formation. Following a change over to a tricone bit early this morning, drilling passed from the arkosic sandstone into an interbedded siltstone/sandstone sequence. This transition corresponds to the western boundary of the low velocity zone identified from the 2005 drilling logs.
Time drilling ended last night at midnight, and the pipe was tripped out. Following some general maintenance of the mud motor and lines, the crew will be tripping back into the hole with the directional drilling assembly. The next couple of days will be devoted to directional drilling into the sandstone formation.
The directional drillers continue to build angle off of the whipstock, in preparation for directional drilling and coring. The ratio of cement to arkosic sandstone in the cuttings is being carefully monitored to make sure that the drill bit is fully out into the formation before we begin to directionally drill to the start of core hole #1.
Preparations are nearing completion for sample handling. Dr.Thomas Wiersberg, from GFZ Potsdam, has recently arrived on site to set up his gas analysis equipment. As during previous phases of the SAFOD project, Thomas' data will provide important information on the fluids and gases entrained in the drill hole during Phase 3.
Preparations are ongoing at the site. Ronald Conze, from the GFZ Potsdam, is setting up and testing the DMT scanner that will be used to photograph the cores.
Preparations continue for the handling of the cores. Brett Carpenter of Penn State and Eric Sandusky of Saint Louis University are preparing tables for the core washing and cutting lab. Brett and Eric will be working onsite this entire summer to help process, describe, and archive the cores.
Dave Kirschner of Saint Louis University is serving as the onsite Core Manager at SAFOD during Phase 3. He is shown here with Brad Carkin of the USGS working on the calibration of a GeoTek core scanner, loaned to SAFOD by the USGS Marine Geology group. The core scanner will be used to photograph the core and measure a variety of geophysical properties (density, magnetic susceptibility, resistivity).
Ronald Conze and Frank Krysiak from GFZ Potsdam arrived today from Potsdam to help install and modify the Drilling Information System. As in Phases 1 and 2, the DIS will be used to store and manage drilling and scientific information in real-time. During Phase 3 it will also incorporate date from the GeoTek core scanner and will interface with the CoreWall system developed by the LacCore group in conjunction with the Electronic Visualization Laboratory. CoreWall will be used onsite to record detailed information about the cores as it is obtained. This information will be made available to the scientific community at the completion of Phase 3.
Rig 37 is upright. The crew will finish preparing the rig tonite, and work on blow-out preventers will start early Thursday morning. Phase 3 is underway!
The site preparation is underway and the drill rig mobilization will begin on Thursday June 14, 2007. Drilling operations are schedule to commence on June 19. Phase 3 has started!
At 3:00 am our coring operations ended successfully as the core barrel reached the rig floor. The science team was on site for immediate core handling, which included marking, sectioning, and subcoring. The core barrel contained 12 feet of 6-inch diameter core, and the core has already been taken to Bakersfield for spectral gamma logging and is on its way to the USGS in Menlo Park. Processing of the core will start on Monday and last throughout next week. On site at present we are almost ready to start the hydraulic fracture test as we attempt to measure the least principal tectonic stress at a vertical depth of over 10,000 ft on the northeast side of the San Andreas Fault!
Our coring efforts are going very well, with the core barrel advancing at a rate of about 4 feet per hour. After the core reaches the surface, some time late tonight, we will cut and box the core, take subcore samples for formation fluids/gas analysis, and begin preparing for tomorrow's hydraulic fracturing test.
This morning we finished drilling through the cement at the bottom of the casing and continued to drill through six feet of fresh rock. We have decided to stop drilling at this depth (13,090 ft) and proceed with the coring, so the core barrel should go into the well late tonight or very early tomorrow morning. We expect the core to come to the surface some time tomorrow. For the remainder of today, caliper and bond logs are being run in the casing to inspect the condition of the well and the quality of the cement job.
The 7-inch casing has been successfully cemented in place, and the drilling crew is currently working to clean the cement out of the bottom of the hole. After this is completed, we will drill approximately 30 feet of new hole and continue to collect cuttings samples. Scientists from the USGS will be arriving towards the end of the week as we begin coring operations.
Now that our open-hole logging and sampling program is completed, the hole will be cleaned and cased and the casing cemented in place over the next 4-5 days. During that time we will be off line until we are ready to initiate coring operations out the bottom of the cased hole.
Today we acquired about 60 sidewall cores from various intervals of the SAFOD borehole. We are now rigging up to condition the borehole for setting casing, which will start in a few days.
Geophysical logging was completed last night. A sidewall coring tool is being run into the hole tonight in an attempt to obtain samples from multiple depths in the hole.
After a successful logging run last night with the super-combo (resistivity, density, neutron and gamma ray) and the sonic tools, acoustic and electrical image logging is well underway. This logging run should be completed later this evening and the science team will use the image logs to finalize where the sidewall cores will be obtained.
We completed our first logging run early this morning and are getting ready for the second. Meanwhile geologists and geophysicists on the science team use some data from the first run along with cuttings analyses and mud gas information to determine the best places in the hole to aim for side-wall cores.
The first pipe conveyed logging run is underway and a preliminary look at the data indicates that the data from this run correlates very well with the LWD data obtained during drilling.
We are currently tripping out of the hole after reaming and conditioning for the last 24 hours. The first geophysical logging run through the San Andreas fault at seismogenic depths will begin during the early hours of tomorrow morning.
Reaming of the borehole is underway and the science team has been busy today taking samples of cuttings from the reaming and catching up on data archiving and processing of samples previously collected.
The science team is happy to announce that drilling of SAFOD was completed today at noon when we reached a total depth of 13082 feet, approximately 150 feet northeast of the surface trace of the San Andreas Fault. Reaming and conditioning of the borehole begins tonight in preparation for geophysical logging operations tomorrow.
Drilling began this morning at 11:50 am with what is likely to be the last bit that will be used during SAFOD Phase 2. We anticipate a further 35 hours of drilling time. The rate of penetration is averaging about 10 ft/hr and the cuttings samples continue to be predominantly shale with less siltstone.
At a depth of 12,804 feet we are tripping out of the hole to replace the drilling bit and we expect to continue drilling tomorrow around noon after reaming the borehole.
Drilling has resumed at 12,570 feet (measured depth) following a routine bit replacement. Cuttings samples (and a fossil fragment from the northeast side of the fault) have been sent to Menlo Park for analysis. Drilling mud samples are being analyzed for grain size distribution and composition to see if there is a change in clay content in the mud before, during and after drilling through the fault zone.
Yesterday, August 2nd, at about 18:35 PDT, we drilled through a very significant fault zone located about 100m SW of the San Andreas surface trace, and within the region where microearthquake data indicate the San Andreas fault to be at 3 km depth. Our first indication of entering the fault zone was a modest increase in drilling rate starting at about 2:30 yesterday afternoon. This early break was comparable to what we've seen when drilling through minor faults or weaker lithologic units - an increase from ~6-9 ft/hr to 12-15 ft/hr. At the same time, an increase in mud gas was observed, particularly radon, hydrogen, CO2 and hydrocarbons. Over the hours that followed we observed a number of very distinct drilling breaks, including one in which we drilled for several feet at rates as fast as 41 ft/hr. Overall, the fault zone appears to be several tens of meters wide with distinct zones characterized by faster drilling. Cuttings from the fault zone itself contain trace amounts of serpentine minerals. Cuttings from the northeast side of the fault are siltier, but it is not yet certain that we have crossed into rocks of the Franciscan formation on the northeast side of the San Andreas. Additional samples will help clarify this. We will continue to collect cuttings, monitor gas, and perform on-site analyses until the next bit trip, which is scheduled for 2:00 am tonight. Drilling should then resume around mid-day tomorrow. We will continue to post frequent updates to this web page throughout the coming days.
Today SAFOD reached a depth of a depth of 12,452 feet at an average of 7 feet per hour. Geologists on site have noticed a slight increase in the amount of crystalline material and calcite veining in the cuttings.
