Fig 1 - uploaded by Gilles Guerin
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Configuration of the DSA/core barrel assembly during a rotary coring, and b piston coring. In b , we show the assembly before and after the core barrel has been pushed into the formation
Source publication
In order to evaluate the efficiency of heave compensation in the Ocean Drilling Program, we developed a device measuring the acceleration of the core barrels. First results show that heave compensation limits bit motion to 10% of the surface heave. We also use the acceleration data to characterize the formation. On rotary corers, acceleration ampli...
Contexts in source publication
Context 1
... principal components of the DSA are a pressure sensor and two accelerometers. The pressure sensor measures pressure in the drill pipe every second, which is used to trigger the recording of acceleration data at a pre- programmed depth. One accelerometer is a vertical- component high-sensitivity transducer, recording motion along the axis of the drill string. The other is a high- frequency three-axis transducer to record bit vibrations. The DSA runs as a self-contained memory device with a battery life allowing 9 h of operations and enough memory to record about 1.5 h of data at a 100-Hz sampling frequency. Before deployment, the DSA is connected through a serial port to a data acquisition PC for initial- ization, and the initial recording depth is defined, typically 100 m above coring depth. After recovery, the DSA is reconnected to the PC and the data are downloaded as Ascii files ready for immediate analysis. The first pro- cessing step is the conversion of the raw data into acceleration, using calibration coefficients provided by the accelerometer manufacturers. The sensors, electronics board, memory and batteries are enclosed in a 1.2-m-long stainless steel pressure case (see Fig. 1) and can operate under temperature and pressure up to 85 ° C and 75 MPa, respectively. Specifications are summarized in Table ...
Context 2
... coring in ODP holes is performed by recovering the core barrel at regular intervals, typically every 9.5 m. The procedure is the same for advanced piston coring (APC) in soft sediments, and for the rotary coring bit (RCB) in harder formations. The empty core barrel free falls to the bottom of the drill string, advances 9.5 m during coring, and then is re- trieved by a wireline which latches to the top of the core barrel. After reaching the rig floor, the core is removed for analysis and an empty core barrel is dropped in the drill string to continue the coring process. The DSA was designed to minimize any impact on coring operations. The tool is initialized before a core barrel is prepared for descent. The DSA is then attached by threaded collars to the top of the core barrel (Fig. 1) and the DSA/core barrel assembly is let free falling to the bottom of the drill string. The top of the DSA can receive the normal core retrieval tool, and the entire assembly is recovered together. Only a few minutes are added to the normal rig floor operations to make and disassemble the DSA/core barrel connection. Before any core analysis is performed (cores must usually rest for a few hours to degas and reach thermal equilibrium), the DSA data are available to assess the coring process and characterize formation ...
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Citations
... Heave is ship motion induced by waves. Its effects on the boat and attached drill string were a very important problem during early drilling operations [Ruddiman et al., 1987;Goldberg et al., 2000;Guerin and Goldberg, 2002;Huey, 2009], and the common use of passive heave compensators in combination with GPS positioning aboard the R/V JOIDES Resolution reduce the heave effects to <50 cm during drilling under normal weather conditions [Iturrino et al., 2013]. For technical reasons, the heave compensators have to be stopped during the few seconds of shooting during APC operations. ...
... 3. Use of a drill string acceleration tool. Experiments carried out by Guerin and Goldberg [2002] show that variations in core-barrel acceleration during coring can be acquired using a relatively simple apparatus. They proposed the addition of an accelerometer directly in the cutting shoe of the APC (in a similar fashion to the APCT-3 cutting shoe that carries a thermoprobe) to allow a timely assessment of the behavior of the core barrel during shooting. ...
Piston cores collected from IODP drilling platforms (and its predecessors) provide the best long-term geological and climatic record of marine sediments worldwide. Coring disturbances affecting the original sediment texture have been recognized since the early days of coring, and include deformation resulting from shear of sediment against the core barrel, basal flow-in due to partial stroke, loss of stratigraphy, fall-in, sediment loss through core catchers, and structures formed during core recovery and on-deck transport. The most severe disturbances occur in non-cohesive (sandy) facies, which are particularly common in volcanogenic environments and submarine fans. Although all of these types of coring disturbances have been recognized previously, our contribution is novel because it provides an easily accessible summary of methods for their identification. This contribution gives two specific examples on the importance of these coring disturbances. We show how suck-in of sediments during coring artificially created very thick volcaniclastic sand layers in cores offshore Montserrat and Martinique (Lesser Antilles). We then analyze very thick, structureless sand layers from the Escanaba Trough inferred to be a record of the Missoula mega-floods. These sand layers tend to coincide with the base of core sections, and their facies suggest coring disturbance by basal flow-in, destroying the original structure and texture of the beds. We conclude by outlining and supporting IODP-led initiatives to further reduce and identify coring disturbances, and acknowledge their recent successes in drilling challenging sand-rich settings, such as during IODP Expedition 340.
... It is therefore critical to minimize downhole tool motion for high quality logging data acquisition. During the Ocean Drilling Program (ODP) and the Integrated Ocean Drilling Program (IODP), Lamont-Doherty Earth Observatory (LDEO) of Columbia University designed and maintained wireline heave compensating systems that supported efficient and high-quality logging data acquisition (Goldberg, 1990; Guerin and Goldberg, 2002; Myers et al., 2001; Sarker et al., 2006). The U.S. Implementing Organization (USIO) decided to replace the previous active heave compensating systems during the 2006–2007 extensive conversion of the D/V JOIDES Resolution in order to reduce rig-up time, improve monitoring quality, and, if possible, improve compensation efficiency. ...
available. doi:10.2204/iodp.sd.15.08.2013
... In marine environments, floating platforms routinely encounter sea surface waves ranging from several cm to a few meters in height that generate both vertical heave and torsional ship motions. A wireline heave compensator is a critical onboard instrument that reduces downhole motion on logging tools deployed from a moving platform, and minimizes motion effects on downhole measurements (Goldberg 1990; Myers et al. 2001; Guerin and Goldberg 2002). During the Ocean Drilling Program (ODP) and the Integrated Ocean Drilling Program (IODP), Lamont- Doherty Earth Observatory (LDEO) of Columbia University, a partner in the US Implementing Organization (USIO), has been providing logging and downhole tool services aboard the JOIDES Resolution, a 143-m-long and 9,719- ton seagoing research vessel that drills core samples and collects measurements below the seafloor (Fig. 1a). ...
... During the Ocean Drilling Program (ODP) and the Integrated Ocean Drilling Program (IODP), Lamont- Doherty Earth Observatory (LDEO) of Columbia University, a partner in the US Implementing Organization (USIO), has been providing logging and downhole tool services aboard the JOIDES Resolution, a 143-m-long and 9,719- ton seagoing research vessel that drills core samples and collects measurements below the seafloor (Fig. 1a). LDEO's Borehole Research Group designed and maintained a wireline heave compensating system that achieved efficient and high-quality logging data acquisition during ODP (1983– 2003) and the IODP Phase I (2003–2005) operations (Goldberg 1990; Sarker et al. 2006; Guerin 2009). However, the LDEO system's configuration, its required maintenance, and its location away from the rig floor motivated the USIO to replace it with a more operationally flexible system that maintains or improves the compensation efficiency and data acquisition quality required by the scientific ocean drilling community. ...
The basic functionality and performance of a new Schlumberger active wireline heave compensation system on the JOIDES Resolution was evaluated during the sea trial and a 3-year period of the IODP Phase II operations. A suite of software programs was developed to enable real-time monitoring of the dynamics of logging tools, and assess the efficiency of wireline heave compensation during down-hole operations. The evaluation of the system effectiveness was performed under normal logging conditions as well as during stationary tests. Logging data were analyzed for their overall quality and repeatability, and to assess the reliability of high-resolution data such as formation microscanner (FMS) electrical images. This revealed that the system reduces 65–80 % of displacement or 88–98 % variance of downhole tool motion in stationary mode under heave con-ditions of ±0.2–1.5 m and water depths of 300–4,500 m in open holes. Under similar water/heave conditions, the com-pensator system reduces tool displacement by 50–60 %, or 75–84 % variance in downhole tool motion during normal logging operations. Such compensation efficiency (CE) is comparable to previous compensation systems, but using advanced and upgradeable technologies, and provides 50– 85 % heave motion and heave variance attenuation. Moreover, logging down/up at low speeds (300–600 m/h) reduces the system's CE values by 15–20 %, and logging down at higher speeds (1,000–1,200 m/h) eliminates CE values by 55–65 %. Considering the high quality of the logging data collected, it is concluded that the new system can provide an improved level of compensation over previous systems. Also, if practically feasible, future integration of downhole cable dynamics as an input feedback into the current system could further improve its compensation efficiency during logging operations.
... Table 1 shows the measurements for each test. These results are similar to those found using drill string acceleration data (Guerin and Goldberg, 2002) and drilling bit parameter data (Myers et al., 2001). The amplitude of downhole acceleration varies between 1.61×10 -3 and 24.4×10 -3 between 0.09 and 0.11 Hz, and between 0.9×10 -3 and 7.4×10 -3 for amplitude of uphole acceleration when linear HMC is not operating. ...
This paper was selected for presentation by an OTC Program Committee following review of information contained in an abstract submitted by the author(s). Contents of the paper, as presented, have not been reviewed by the Offshore Technology Conference and are subject to correction by the author(s). The material, as presented, does not necessarily reflect any position of the Offshore Technology Conference, its officers, or members. Papers presented at OTC are subject to publication review by Sponsor Society Committees of the Offshore Technology Conference. Electronic reproduction, distribution, or storage of any part of this paper for commercial purposes without the written consent of the Offshore Technology Conference is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of where and by whom the paper was presented. Write Librarian, OTC, P.O. Box 833836, Richardson, TX 75083-3836, U.S.A., fax 01-972-952-9435. Abstract Recovery of cores and logging data from a dynamically positioned drill ship introduces significant heave related depth uncertainties. Heave compensation plays a pivotal role in assuring downhole data integrity by countering the effects of the ship's heave while tools are downhole. A linear displacement wireline heave compensation system has been in routine use on the D/V JOIDES Resolution since 1988. A rotary heave compensation system has been designed for the IODP recently to replace the linear unit. The new rotary unit consists of an electro-hydraulic winch, supporting position sensors, electronics and software to add and remove cable slack in response to ship heave. Analysis of acceleration logs recorded from downhole tools in both time and frequency domain compares the effectiveness of the linear and rotary heave motion compensators. Fourier amplitude spectra of uphole and downhole acceleration indicate that compensation reduces the heave influence on downhole acceleration by an order of magnitude for both compensation systems. These results are consistent for a variety of downhole tools, and suggest an average of 52-74% variance reduction in downhole acceleration for the linear system. Analysis of acceleration data with the rotary heave compensator system shows 75-80% variance reduction between the uphole and downhole spectra. Although these results are preliminary, our analysis shows comparable effectiveness of the rotary and linear compensation systems.
We established a cable-free memory-logging system for drill-string-deployed geophysical borehole measurements. For more than 20 years, various so-called “logging while tripping” (LWT) techniques have been available in the logging service industry. However, this method has rarely been used in scientific drilling, although it enables logging in deviated and unstable boreholes, such as in lacustrine sediment drilling projects. LWT operations have a far lower risk of damage or loss of downhole logging equipment compared with the common wireline logging. For this purpose, we developed, tested, and commissioned a modular memory-logging system that does not require drill string modifications, such as special collars, and can be deployed in standard wireline core drilling diameters (HQ, bit size of 96 mm, and PQ, bit size of 123 mm). The battery-powered, autonomous sondes register the profiles of the natural GR (gamma radiation) spectrum, sonic velocity, magnetic susceptibility, electric resistivity, temperature, and borehole inclination in high quality while they are pulled out along with the drill string. As a precise depth measurement carried out in the drill rig is just as important as the actual petrophysical downhole measurements, we developed depth-measuring devices providing a high accuracy of less than 0.1 m deviation from the wireline-determined depth. Moreover, the modular structure of the system facilitates sonde deployment in online mode for wireline measurements.
One of the main challenges during coring, particularly in exploration wells, is the possibility of unidentification of the right coring point/depth. Typically, this can be noticed only at the surface using gamma-ray logging or geology study. In such cases, the retrieved core sample is already obtained from the undesired formation or interval and thus, the success of the operations has been seriously challenged as a lot of money and efforts have been wasted. Facing this challenge, coring may be repeated (this time trying to be in the right depth interval). Ignoring to core and just relying on subsequent wireline logs for formation evaluation is not an option in an exploration well (because the logs would remain uncalibrated without core data and of limited value). Another challenge of coring (and generally formation evaluation) is that coring and wireline logging are taken under different times and thus well and formation conditions causing some adverse mud invasion or mechanical changes, and even depth matching issue (refer to Chap. 8).
MTi motion sensor measured the heave motion of the supporting ship. The motion of the MTi was controlled by a servo-motor system which determined the period and range of heave motion. The integral of output of MTi acceleration was dealt with a digital high-pass filter which eliminate the low-frequency noises. So the heave speed of the supporting ship was obtained. The simulation model was set up. And the semi-physical simulation test was done with the input of velocity that measured by MTi. Semi-physical simulation test shows that active heave compensation unit of underwater vehicle is a good way to improve the security of underwater vehicle.
The scientific drilling vessel Chikyu has started drilling at Nankai trough under the international organization, IODP. The Nankai trough located beneath the ocean off the southwest coast of Japan is one of the most active earthquake zones on the planet and one of the best-studied subduction zones as well. The Nankai Trough Seismogenic Zone Experiment attempts for the first time to drill, sample, and instrument the earthquake-causing or the seismogenic portion of Earth’s crust, where violent, large-scale earthquakes have occurred repeatedly throughout history. Before starting the international drilling operations, an integration drilling test off Shimokita Peninsula was conducted and we acquired actual drilling data such as vessel heave, hook load, and compensator position. Confirming its validity, data acquisition systems have worked continuously in international drilling operations. It is very important to consider the actual drilling data for the drilling operation and for further technical development. This paper describes the scientific drilling programs of the drilling vessel Chikyu and the drilling data acquisition for future technical development in relation with the sample data acquired in the internal drilling operations.
The scientific drilling vessel Chikyu was designed to have the capability to drill down to 10,000 m total vertical depth and to obtain core samples. To reach such deep drilling and to recover scientifically worthy core samples, it is important to know the drill pipe dynamics using the actual drilling data for strength evaluation of the drill pipe and for control of a drill bit.
To reach such deep drilling, a fine strength evaluation is mandatory because there is little margin. So, the estimation of dynamic tension due to vessel heave motions is necessary. During the design phase, strength evaluation of the drill pipe is conducted under several assumptions. To ensure the strength of the drill pipe, it is important to utilize data acquired from actual drilling operations and to verify the analysis model. Furthermore the core recovery rate is affected by the variation of the weight on bit caused by the propagation of the vessel heave motions. Therefore, a heave compensating system will be used and it is very important to evaluate the performance.
Thus, the authors have acquired the drilling data including the vessel motions, the hook load variations and the motion of the heave compensator. And analysis with actual drilling data shows the dynamic tension that was actually exerted and the basic performance of the heave compensator. This paper described that the dynamic tension considering influence of the compensator and also the performance of the heave compensator from the viewpoints of following capability including a phase difference. Actual drilling data provided the worthy information on the drill pipe dynamics. The considerations will be utilized for future operations such as Tohoku Earthquake Drilling Program and Nankai Trough drilling programs and also for future technical development.
In order to reduce the influence of the bench extraction equipment from the working deep-water exploration ship when it has swing or heave movement by wind and waves, according to the 3000m deep-water exploration ship work condition and the structural parameters, through analysing and calculating, wave compensation control system of deep-water exploration ship bench extraction equipment was researched. Modeling and simulation analysis were done used by dynamic system software Matlab/simulink which has the functions of modeling and simulation. So that displacement response simulation curve of wave compensation system was obtained, which can be utilized to analyze the motion compensation effect of bench further.
