Patent Application
20210079782
Well logging is the practice of making a detailed record (a “well log”) of the geologic formations penetrated by a borehole. The log may be based on physical measurements made by 15 instruments lowered into the hole. Logging tools may measure the natural gamma ray, electrical, acoustic, stimulated radioactive responses, electromagnetic, nuclear magnetic resonance, pressure and other properties of the rocks and their contained fluids. The data itself is recorded either at surface (e.g., real time mode), or in the hole (e.g., memory mode) to an electronic data format and their either a printed record or electronic presentation called a “well log” is provided. Well logging operations can either be performed during the drilling process, i.e., logging-while-drilling, to provide real-time information about the formations being penetrated by the borehole, or once the well has reached Total Depth and the whole depth of the borehole can be logged.
Wireline logging is performed by lowering a “logging tool”- or a string of one or more instruments—on the end of a wireline into an oil well or borehole and recording petrophysical properties using a variety of sensors. Logging-while-drilling (“LWD”) is a technique of conveying well logging tools into the well borehole downhole as part of the bottom hole assembly (“BHA”). LWD tools work with a measurement-while-drilling (“MWD”) system to transmit partial or complete measurement results to the surface via typically a drilling mud pulser or other techniques, while LWD tools are still in the borehole, which is called real-time data. Complete measurement results can be downloaded from LWD tools after they are pulled out of the hole, which is called “memory data.”
Typically, LWD tools require complex interfacing between the different tools in the BHA, e.g., data links, mechanical, electrical, EE FW and EE SW. The data links in the BHA are often prone to failure and expensive to repair. Highly trained field engineers may be needed to assemble, program, run the tools and interpret the data. What is more, the BHA often employs communication and a power bus providing power and controlling all the tools in the BHA. It is common if one tool fails, to compromise the job.
What is needed then is an improved logging-while-drilling assembly. Advantageously, the present application pertains to a self-powered logging-while-drilling assembly. The assembly has a body comprising a releasable hatch and a battery within said body configured to power the assembly. A memory and/or processor may be employed with a resistivity micro-imager and/or a spectral gamma sensor.
A logging-while-drilling (“LWD”) assembly is disclosed. The logging-while-drilling assembly is a self-powered and stand-alone tool. That is, the logging-while-drilling assembly is not dependent upon any external power or communications to function reliably and may be run anywhere in the drilling string, for instance above the mud motor and below the MWD system. Operators may employ the logging-while-drilling assembly when drilling info is not needed in real-time and instead can download the data after the run to decide where to shoot and frack.
The LWD assembly may be synchronized at the surface with a measurement-while-drilling (“MWD”) system in the drilling string for depth correlation for data processing after the job. All measurements are processed and stored in memory and raw data is recorded for quality control. The LWD assembly may be configured to independently acquire a high side tool face angle used for imaging of deviated wells. The LWD assembly is full autonomous and independent from any other tools in the drilling string. The LWD assembly is self-powered by its own dedicated power source of any kind. The LWD assembly is initialized after power-up by synchronizing the tool clock with the LWD assembly. The LWD assembly primarily uses cables and connectors for power up, synchronization and data download or dump after the job. In certain embodiments, the LWD assembly's only interaction with any other tools in the drilling string (if any other tools are present) is to synchronize the tool clock for performing depth correlation of the data after the run. In yet other embodiments, the LWD assembly may be run even without any other tool in the drilling string, and in this case, the depth correlation may be performed using a drill chart.
The LWD assembly may be configured having a smart power safe mode by detecting rotation and vibration, e.g., a “sleep” mode when RPM=0 and there is no vibration. In certain instances, WiFi may be an option when power availability is not an issue, e.g., as is often the case for short tool runs. If the WiFi is not reliable due to interference around the rig floor, the programming and the data download after the run may be performed through a data port using cable and any standard connectors.
The LWD assembly micro imager includes a guard electrode 18 and imaging electrodes 21 and 23. The guard electrode 18 is isolated from the body 1 with isolator 17 and locked to the body 1 with fasteners 20 thru isolators 19. The imaging electrodes 21 and 23 are isolated from the body 1 thru isolators 22 and 24. The LWD assembly wiring is configured using cross drilling between the pockets, which is well understood by those skilled in the art.
One or more hatches may be sealed using face seals or single/double “O” ring seal configurations understood by those skilled in the art. The number of cavities may vary with the diameter of the LWD assembly, e.g., the number is higher for large diameters and lower for small diameter tools.
Advantageously, operators may save significant costs by running the LWD assembly on its own and obtaining valuable well data for future well design stages while paying only a fraction of the typical cost. The LWD assembly processes the measurement data and stores both raw and processed data. The raw data and readings of the magnetic and gravitational fields may be used for validating the measurements; the processed data may then be used for a fast initial assessment of the well.
In additional embodiments one may replace spectral gamma with another suitable type of measurement or combination of measurements. For example, a resistivity measurement may be useful. The type of resistivity measurement employed may depend on the well, its characteristics, and the desired results. However, one type of useful resistivity may be azimuthal resistivity and more particularly one in which it is used as a standalone measurement. Such measurements and tools therefore are described in, for example, the following U.S. Pat. Nos. which patents are incorporated herein by reference:
The present application claims priority to U.S. provisional application 62/901,301 filed Sep. 17, 2019 which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62901301 | Sep 2019 | US |
