Patent Publication Number: US-2017350201-A1

Title: Data Logger, Manufacturing Method Thereof and Data Acquisitor Thereof

Description:
CROSS REFERENCE OF RELATED APPLICATION 
     This is a non-provisional application that claims the benefit of priority under 35 U.S.C.§119 to a provisional application, application number 62335705, filed May 13, 2016. 
    
    
     NOTICE OF COPYRIGHT 
     A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to any reproduction by anyone of the patent disclosure, as it appears in the United States Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. 
     BACKGROUND OF THE PRESENT INVENTION 
     Field of Invention 
     The present invention relates to a data logger and manufacturing method thereof, and more particularly to a data logger using in measuring during drilling and a data acquisitor for acquire data from the data logger. 
     Description of Related Arts 
     For drilling operation, tough environment is the most difficulty and the most important factor to technology development. Because of harsh environment, like up to 15,000 psi and 250° C. or even higher, all downhole operation is with high temperature and high pressure. Also during drilling, drilling fluid and additives used causes corrosion resistance requirements. Therefore acquiring and monitoring environment data are critical, while detect the potential safety issues is crucial and necessary. 
     A drilling system  90 P is illustrated in  FIG. 1 . The drilling system  90 P comprises at least one mud pump  91 P, a mud tank  92 P stored with Drilling Fluid, and a drillstring  93 P. The drilling fluid is driven by the mud pump  91 P into the drillstring  93 P while drilling borehole. 
     The drillstring  93 P further comprises a drillpipe  931 P, a drillcollar  932 P and a drillbit  933 P. The drilling fluid is introduced into the drillpipe  931 P from the mud tank  92 P by applying pressure from one or more mud pump  91 P. Then the drilling fluid passes into the drillpipe  931 P, the drillcollar  932 P and reaches to the drillbit  933 P in bottomhole. The drillbit  933 P comprises at least one nozzle for the drilling fluid spring out of the drillstring  93 P. One skilled in the art will understand that the drilling fluid circulates uphole in the annulus section and is then discharged into the mud tank  92 P via a return flow line. So the cuttings generated by the drilling operation are carried by the drilling fluid from the bottomhole to the surface. 
     The drilling system  90 P comprises a shale shaker  94 P. Later back on the surface, the shale shaker  94 P will separate comparatively large cuttings or other solids from the drilling fluid. Then, the drilling fluid is discharged into the mud tank  92 P and is prepared to circulate again by applying the mud pump  91 P. 
     After reaching to the surface, the drilling fluid with cuttings passes along the return flow line and then reaches to a shale shaker, where comparatively large cuttings or other solids can be separated from the drilling fluid. 
     The traditional measurement-during-drilling (MWD) technology is widely used for acquisition of data during drilling operation in a system as disclosed above. The information collected includes pressure, temperature, deviation directional surveys and so on. 
     Although the traditional system is useful, it does have its own limitations. Most of sensors of the MWD system are installed near the drillbit  933 P. Therefore, only the information at the drillbit  933 P can be measured. However, the parameters over the entire borehole, such as temperature or pressure profile, cannot be accessed by traditional MWD system. In addition, MWD system is typically expensive and requires much manpower and time to operate. Moreover, the transmission data rate is extremely low (less than 10 bit/s) because most MWD system still uses mechanical way, like mud pulse telemetry, to communicate between bottomhole and surface as the distance between bottom and surface reaches 12,000 ft and more. 
     In order to fit the drilling operation, measurement has to face harsh conditions. This leads to many problems. The encapsulated cover meets communication method. The efficient sensor meets battery problems. Nice data meets data acquisition problems, even in an acceptable data rate. And all design must consider the requirement of ultra-small size, which is adapted for the drilling system  90 P avoiding huge cost of improvement 
     As reasons mentioned, there is a need to provide a cost-effective device and system capable of measuring and storing downhole parameters, such as temperature and pressure over the entire borehole in real-time. 
     SUMMARY OF THE PRESENT INVENTION 
     The invention is advantageous in that it provides a data logger, wherein the data logger is adapted for measuring environmental data during drilling, so as to provide acquiring and monitoring borehole conditions by a data acquisitor. 
     Another advantage of the invention is to provide a data logger, wherein the parameters over the entire borehole is received by the data logger, while the data logger carried by the drilling fluid. 
     Another advantage of the invention is to provide a data logger, wherein the data logger is adapted to drilling system which reduces cost greatly and the data logger is in ultra-small size to fit the drillstring of the drilling system. 
     Another advantage of the invention is to provide a data logger, wherein the measurement system further comprises an initiator, an injector, a recoverer, a data acquisitor, and a charger cooperated with the measurement of the data logger, so as the data acquisitor is capable to collect and record data over the whole borehole. 
     Another advantage of the invention is to provide a data logger, wherein the data logger is turned on by the initiator to be waked up before measuring and the data logger gets a start signal to record data. 
     Another advantage of the invention is to provide a data logger, wherein the data logger is injected into borehole by the injector to begin measuring and be carried by the drilling fluid, so as to ensure the data logger to be carried by the drilling fluid into the borehole. 
     Another advantage of the invention is to provide a data logger, wherein the acquisitor provides an acceptable data rate of the transmission data rate of the data logger to increase efficiency of measurement. 
     Another advantage of the invention is to provide a data logger, wherein the data logger is carried by the drilling fluid to travel over the drillstring and the borehole, so as to collect and record data which highly valuable to analysis environment during drilling. 
     Another advantage of the invention is to provide a data logger, wherein the data logger is distributed collecting data to detect the potential safety issues and reduce costs of drilling. 
     Another advantage of the invention is to provide a data logger, wherein the data acquisitor is capable to provide temperature and pressure profile of the borehole. 
     Another advantage of the invention is to provide a data logger, wherein the data logger is made in ultra-small size, such as less than 7.5 mm, in order to pass through the nozzle of the drillbit and all of devices of the measurement system is suitable for micro size data interface. 
     Another advantage of the invention is to provide a data logger, wherein the data logger is capable to be exposed in the harsh environment in long time traveling of measurement. 
     Another advantage of the invention is to provide a data logger, wherein the data logger receives energy in plug charging or in wireless charging with non-contacting method to transmit energy to the data logger by the charger. 
     Another advantage of the invention is to provide a data logger, wherein the data logger comprises a sensor unit which further comprises a pressure sensor in ultra-small size with high measurement range and can be used in high pressure environments, so as the conditions of the borehole can be measured. 
     Another advantage of the invention is to provide a data logger, wherein the data logger is capable to suffer mechanical strength, thermal properties, and resistance to chemicals, so as to measure the environment of the borehole efficiently. 
     Another advantage of the invention is to provide a data logger, wherein the manufacturing of the data logger further considers the density of the data logger to enhance mobility so that data loggers can be carried efficiently by the drilling fluid through the entire wellbore. 
     Another advantage of the invention is to provide a data logger, wherein in consider of sensor efficiency, power supply, data storage and transmission, the data logger and the measurement system is well operational in actual drilling industry. 
     Additional advantages and features of the invention will become apparent from the description which follows, and may be realized by means of the instrumentalities and combinations particular point out in the appended claims. 
     According to the present invention, the foregoing and other objects and advantages are attained by a data logger, comprising: 
     a mainboard; and 
     a jacketing, wherein the mainboard is covered with the jacketing, wherein the data logger is capable to be carried by said drilling fluid traveled in borehole, wherein the data in borehole is collected by the mainboard of the data logger during traveling. 
     According to the embodiments of the present invention, wherein the main board of the data logger further comprises a controller, a sensor unit, a power unit, a communication unit and a board body for supporting the controller, the sensor unit, the power unit and the communication unit together, wherein the sensor unit and the communication unit are controlled by the controller, wherein the controller, the sensor unit and the communication unit are supplied power by the power unit, wherein the sensor unit is capable to collect environment data which waited to be transmitted through the communication unit. 
     According to the embodiments of the present invention, wherein the controller, the sensor unit, the power unit and the communication unit are electrically connected to each other. 
     According to the embodiments of the present invention, wherein the main board of the data logger further comprises a storage unit, wherein the sensor unit is capable to collect environment data to be storage in the storage unit. 
     According to the embodiments of the present invention, wherein the main board of the data logger further comprises a switch, wherein the switch is turned on to wake up the controller, the sensor unit, the storage unit and the communication unit. 
     According to the embodiments of the present invention, wherein the switch is a photo detector. 
     According to the embodiments of the present invention, wherein the communication unit further comprises at least one connector connected the storage unit to be read from outside the data logger. 
     According to the embodiments of the present invention, wherein the communication unit is at least two pads connected to the surface of the data logger. 
     According to the embodiments of the present invention, wherein the storage unit is a flash memory. 
     According to the embodiments of the present invention, wherein the power unit further comprises a receiving unit and a rechargeable battery, wherein the receiving unit is received power to charge the rechargeable battery for the rechargeable battery provides power supply to the controller, the sensor unit, the storage unit, the switch and the communication unit. 
     According to the embodiments of the present invention, wherein the sensor unit further comprises a pressure sensor, wherein the pressure sensor collects pressure data of environment as the data logger travels in borehole. 
     According to the embodiments of the present invention, wherein the sensor unit further comprises a temperature sensor, wherein the temperature sensor collects temperature data of environment as the data logger travels in borehole. 
     According to the embodiments of the present invention, wherein the pressure sensor further comprises a pressure sensor chip and a bonding elements, wherein the bonding elements is electrical connected and fixed the pressure sensor chip with the board body. 
     According to the embodiments of the present invention, wherein the pressure sensor chip and the boding elements are packaged by a sealing layer which is covered a non-sensing area of the pressure senor chip to expose a sensing area of the pressure sensor chip. 
     According to the embodiments of the present invention, wherein the pressure sensor further has a sensing channel formed by the sealing layer to make the sensing area of the pressure sensor chip efficient to sense the pressure and collect data of pressure. 
     According to the embodiments of the present invention, wherein the sensing channel is formed integrated by the sealing layer. 
     According to the embodiments of the present invention, wherein the jacketing is compound by sealing materials and density control materials. 
     According to the embodiments of the present invention, wherein the data logger further comprise a shell outside the jacketing to enhance the resistance to chemicals. 
     According to the embodiments of the present invention, wherein the data logger has diameter less than 7.5 mm. 
     In accordance with another aspect of the invention, the present invention comprises a data acquisitor to acquire data from at least one data logger as recited above, comprising: 
     at least one seat for placing the data logger; 
     a transmitting connector set inside the seat; and 
     an acquisition board to acquire data recorded in the data logger through the transmitting connector and the connectors of the communication unit of the data logger. 
     According to the embodiments of the present invention, wherein the data of the data logger is acquired by the acquisitor to be further analyzed. 
     In accordance with another aspect of the invention, the present invention comprises an acquisition method of the measurement system as recited in claim  20 , comprising following steps: 
     identify the data logger; and 
     downloading data from the data logger. 
     In accordance with another aspect of the invention, the present invention comprises a method of manufacturing the data logger as recited above, comprises following steps: 
     assembly the main board of the data logger; 
     placing the main board in a mould; 
     pouring the material of the jacketing between the main board and the mould; 
     solidifying the jacketing and demoulding; 
     placing the mould on the other side of the main board; 
     pouring the material of the jacketing between the main board and the mould; and 
     solidifying the jacketing and demoulding to be the data logger. 
     According to the embodiments of the present invention, wherein the mould is shaped in cup-shape. 
     According to the embodiments of the present invention, wherein during pouring the material of the jacketing further comprises putting density control materials inside. 
     According to the embodiments of the present invention, wherein the density control materials is selected from low density epoxy foam, aerogel and glass microsphere. 
     According to the embodiments of the present invention, wherein after the step of solidifying the jacketing and demoulding to be the data logger, the method further comprises following steps: 
     placing the main board in the mould; 
     pouring the material of the shell between the main board and the mould; and 
     solidifying the shell and demoulding. 
     Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings. 
     These and other objectives, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of a traditional measurement-during-drilling (MWD) technology in a drilling system. 
         FIG. 2  is a perspective view of a data logger of a real-time measurement system according to a preferred embodiment of the present invention. 
         FIG. 3  is a schematic view of the real-time measurement system according to the above preferred embodiment of the present invention. 
         FIG. 4  is a real product picture of the data logger before measurement and after measurement according to the above preferred embodiment of the present invention. 
         FIG. 5  is a perspective view of the main board of the data logger of a real-time measurement system according to the above preferred embodiment of the present invention. 
         FIG. 6  is a perspective view of an alternative mode of the main board of the data logger of a real-time measurement system according to the above preferred embodiment of the present invention. 
         FIG. 7  is an example temperature profile of the data logger of a real-time measurement system according to the above preferred embodiment of the present invention. 
         FIG. 8  is an example pressure profile of the data logger of a real-time measurement system according to the above preferred embodiment of the present invention. 
         FIG. 9  is a front view of the data acquisitor of the data logger according to the above preferred embodiment of the present invention. 
         FIG. 10  is a schematic view of the data acquisitor of the data logger transmitting data to a computer according to the above preferred embodiment of the present invention. 
         FIG. 11  is a schematic view of the data acquisitor of the data logger according to the above preferred embodiment of the present invention. 
         FIG. 12  is a flow chart of the real-time measurement system according to the above preferred embodiment of the present invention. 
         FIG. 13  is a block diagram of the data logger according to the above preferred embodiment of the present invention. 
         FIG. 14  is a schematic view of the molds for manufacturing the data logger according to the above preferred embodiment of the present invention. 
         FIG. 15  is a flow chart of manufacturing the data logger according to the above preferred embodiment of the present invention. 
         FIG. 16  is a schematic view of the density control during manufacturing the data logger according to the above preferred embodiment of the present invention. 
         FIG. 17  is a product picture of the data logger according to the above preferred embodiment of the present invention. 
         FIG. 18  is a flow chart of an alternative mode of manufacturing the data logger according to the above preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following description is disclosed to enable any person skilled in the art to make and use the present invention. Preferred embodiments are provided in the following description only as examples and modifications will be apparent to those skilled in the art. The general principles defined in the following description would be applied to other embodiments, alternatives, modifications, equivalents, and applications without departing from the spirit and scope of the present invention. 
     One skilled in the art will understand the technical term used in the present invention, such as drilling, drillstring, shale shaker, drillpipe, drillcollar, drillbit, drilling fluid and so on, are sample of application situation of the preferred embodiments of the present invention. 
     A data logger  10  is provided in a preferred embodiment of the present invention, as shown in  FIG. 2 . The data logger  10  is a kind of small SoC (System-on-Chip) system for understanding, which can sensor parameters of the surrounding environment, record data, transmit data and supply power for its working. As the surrounding environment is not common, the data logger  10  has to face to extremely harsh conditions in the universe, for example in the borehole of drilling or the bottom of abysmal sea. As the data collected by the data logger  10  is priceless, the importance of the data logger  10  is incomparable to traditional loggers and the measure system of the data logger  10  has to be fully considered around the data logger  10 . 
     The data logger  10  comprises a mainboard  11  and a jacketing  12 , wherein the mainboard  11  is covered with the jacketing  12  to packaging the mainboard  11  to protect the mainboard  11 . The jacketing  12  is made of chemical materials that is corrosion resistant, so as to encapsulate the mainboard  11  in a protective coating to be functional during operating. It is worth to mention that the jacketing  12  is compound by sealing materials and density control materials to avoid the data logger  10  to be effected by gravity since the mainboard  11  is almost made of electrical metal. Therefore, the data logger  10  is preferably adapted to drilling operation, which can be carried by the drilling fluid traveled the whole borehole and recycled by the drilling system. 
     A real-time measurement system  100 , as shown in  FIG. 3 , comprises at least one data logger  10 , an initiator  20  for turning on the data logger  10 , an injector  30  to inject the data logger  10  into borehole, a recoverer  40  to get the data logger  10  back from borehole, a data acquisitor  50  to transmit data from the data logger for analyzing, and a charger  60  for supplying power to the data logger  10 . Since the drilling fluid traveling the whole borehole drove by the drilling system, the data logger  10  can be carried to collect environment data continually to measure situation of borehole in real-time. It is worth to mention that the real-time measurement system  100  needn&#39;t be set in advance to the drilling system to reduce lots of cost. 
     As the density of the data logger  10  is to be controlled near to the drilling fluid, the data logger  10  can be carried by the drilling fluid to travel the whole borehole and be recycled to download data that collected in the borehole. The data logger  10  can collect several kinds of parameters during traveling, including pressure, temperature, acceleration, γ-ray and so on and be to profile according to the time from initiation to acquisition which lasts up to 2 hours about 15,000 ft well. 
     In operation, it is preferably that several the data loggers  10  are inject in borehole and carried by the drilling fluid. It is worth to mention that each of the data logger  10  is individual which is hardly to affect others. It measures temperature, pressure and other parameters continuously after it is initiated by the initiator  20 . The initiator  20  is preferably to be an optical signal transmitter. The initiator provides an optical signal to the data logger. This signal may be a visible light, or an invisible light including infrared light and ultraviolet light. The switch  121  in the data logger  10  receives the optical signal and wake up the data logger  10  from deep sleep mode. After the initiation, the data logger  10  is able to start measurement at adjustable sampling rate, for example, 1 second per sample or 2 seconds per sample. The sampling rate of the data logger  10  can be modified by programming. Each sampling cycle in different sampling rate, for example, in 1 second per sample, only 1/100 seconds is taken by the data logger  10  to complete the measurement and store the data. Data logger  10  is in power saving mode in other 99/100 seconds. The strategy of power management can help the data logger  10  work long enough with a limitation of the battery capacity. 
     When multiple the data loggers  10  are initiated by the optical signal sent from the initiator  20 , they are all deployed into the top of drillpipe when making pipe connection. In one embodiment, the data loggers  10  are incorporated into a certain amount of high viscosity fluid to be injected into the drilling fluid. The data loggers  10  are circulated together with the drilling fluid inside the drillstring. Then they reach to the drillbit and pass through the nozzles. In operation, a short distance, for example, 10 ft should be kept between the nozzles and the bottomhole. This can reduce the impact force when the data loggers  10  hit on the bottom wall the well since the jet velocity from the nozzles is very high. The data loggers are circulated upward in the annulus section and reach to the shale shaker. The data loggers  10  and cuttings generated downhole during drilling operation are separated from the drilling fluid on the shale shaker. A group of magnetic strips are placed on the shale shaker, so the metal part inside the data loggers  10  can be attracted by the magnetic strips. All the survived data loggers  10  are retrieved on the magnetic strips. During the trip with the drilling fluid in the borehole, the data loggers always take measurement and store the measurement data continuously. The data loggers  10  are then connected to the data acquisitor  50  for the data downloading process. 
     The data logger  10  further comprise a shell  13  outside the jacketing  12  to enhance the resistance to chemicals. The shell  13  is optional since the jacketing  12  is well sealed the main board. It is worth to mention that the shape of the data logger  10  is selectable from ball, ellipsoid, hemisphere and so on which can be decide by the shell  13  or the jacketing  12 .  FIG. 4  is a picture of the data logger before measurement and after measurement according to the preferred embodiment of the present invention. The shape won&#39;t be changed because of the shell  13  or the jacketing  12 . 
     A flow chart of the measurement system  100  is illustrated in  FIG. 12 . The data logger  10  is turned on by the initiator  20  and waked all sensors to collect data. The initiator  20  provides switch signal  200  to the data logger  10 , for example optical signal, electrical signal or magnetic signal, to start the measurement of borehole. Then the data logger  10  can be injected in borehole by the injector  30  which provides injecting power  300  to place the data logger  10  in the drilling fluid. The data logger  10  later be recovered by the recoverer  40  out of the drilling fluid. Finally, the data of the data logger  10  is acquired by the acquisitor  50  to be further analyzed. What is more, the data logger  10  can be charged by the charger  60  as needed when back from borehole. And if the data logger  10  out of power during in borehole, the measurement will be pause but the data logger  10  still can be carried back by the drilling fluid and be recycled to be charged. 
     As disclosed above, the method of measurement of the measurement system  100  comprises following steps: 
     Initiating the data logger  10  to prepare to collect data; 
     Injecting the data logger  10  into borehole; 
     Collecting data by the data logger  10  which carried by drilling fluid; 
     Recovering the data logger  10  from the drilling fluid; and 
     Downloading data from the data logger  10 . 
     Further, before injecting or after collecting data, the method further comprises following steps: 
     Charging the data logger  10 . 
     The step of initiating the data logger  10  further comprises receiving a switch signal  200  to initiating the data logger  10 . 
     The step of injecting the data logger  10  can be manual or mechanical, which the data logger  10  is forced by an injecting power  300 . 
     In an alternative mode of the preferred embodiment, the step of downloading data and charging can be synchronous. 
     After downloading the data, the data logger  10  can be reused for next measurement. 
     Furthermore, as shown in  FIG. 13  the main board  11  of the data logger  10  further comprises a controller  111 , a switch  112 , a sensor unit  113 , a power unit  114 , a communication unit  115 , a storage unit  116 , and a board body  110  for supporting the controller  111 , the switch  112 , the sensor unit  113 , the power unit  114 , the communication unit  115  and the storage unit  116  together. The switch  112  is preferably to be a photo detector  1121  in the preferred embodiment. The communication unit  115  further comprises at least one connector  1151  connected the storage unit  116  to be read from outside the data logger  10 . The storage unit  116  is preferably to be a flash memory  1161  in the preferred embodiment. One skilled in the art will understand that the controller  111 , the switch  112 , the sensor unit  113 , the power unit  114 , the communication unit  115  and the storage unit  116  are electrically connected to each other. And the sensor unit  113  is capable to collect environment data to be storage in the storage unit  116  waiting to be transmitted through the communication unit  115  later back to the data acquisitor  50 . The power unit  114  provides power to the controller  111 , the switch  112 , the sensor unit  113 , the communication unit  115  and the storage unit  116  for working. 
       FIG. 5  shows an alternative mode of the preferred embodiment of a data logger  10  with the temperature sensor  1132  used in the system. The main board  11  of the data logger  10  comprises the controller  111  with an internal flash memory, a photo detector  1211 , a light-emitting diode (LED) and a temperature sensor  1132  and other relative components such as resistors and capacitors. An external flash memory  1161  may be added when higher data capacity is needed. The main board  11  has to be designed in an ultra-small size, low cost and low power consumption, for example, a round microchip has 5 mm in diameter. The power unit  114  is preferably selected for a small size and a large capacity. It may be a lithium rechargeable battery. A small size power unit  114  may be an inductive coil, which uses an electromagnetic field to obtain energy from the external inductive coil in a charging base station. All the components are encapsulated in a protective shell and comprise a spherical shape. The jacketing  12  may be a transparent, high mechanical strength, high glass transition temperature resin, epoxy or conformal coating. So it is able to protect the components on the mainboard  11  away from the harsh high temperature high pressure downhole conditions. Also, the density of the jacketing  12  should be close to the drilling fluid density so data loggers  10  are able to move with drilling fluid. The communication unit  115  which preferred to be two pads  1151  connected to the interface of the mainboard  11  is placed on the surface of the data logger  10 . During data downloading process, the two pads  1151  are used to connect to the data acquisitor  50  to establish a communication between data logger  10  and the data acquisitor  50 . 
     The controller  111  provides system control, data conversion and management of the data logger  10 . It is preferably selected for ultra-small size, low power microcontroller in the market. The storage unit  116  may be an individual external memory chip to store the measurement data and other information including ID of the data logger. A photo detector  1211  detects the optical signal  200  sent from the initiator  20  and then enables the microcontroller to enter the work mode. The LED controlled by the controller  111 , is used to inform the operator the status of the data logger  10 . For example, when the data logger  10  is under charging, the LED stays on; when the data logger  10  is initiated, the LED turns off; when the data logger is sampling, the LED starts blinking; when the battery runs down, the LED turns off again. 
     The temperature sensor  1132  is an ultra-small size, low power and high precision component. The temperature sensor  1132  may be a digital output type, which has a microcontroller compatible interface for data management; or an analog output type, which need an analog-to-digital converter (ADC) inside the controller  111  to convert the output to the digital data so it can be stored into the storage unit  116 . 
       FIG. 6  shows an alternative mode of the preferred embodiment of a data logger  10  used in the system  100 . The pressure sensor  1311  comprises a pressure sensor chip  11311 . The pressure sensor chip  11311  may be in a small size that can measure pressure in fluid, clean air or non-corrosive gas environment. Connection wires may be used between the mainboard  11  and the pressure sensor  1311 . A small size (1 mm diameter) hole needs to be drilled on top of the pressure sensor  1311  to make a contact area between the pressure sensor  1311  and drilling fluid when the data logger  10  is circulating downhole. 
     Downhole pressure measurement may vary from a few thousands psi to tens of thousands psi. Normally the accuracy of the ADC in the controller  111  is not high enough for the downhole pressure measurement. Therefore, in order to have a precise pressure measurement, an external high precision ADC may be used to convert the pressure measurement. This ADC may have low power consumption, high resolution with a compatible interface to the microcontroller. 
     In addition, the sensor unit  113  further comprises an accelerometer  1133 , a γ-ray sensor  1134 , a sonic sensor  1135 , a PH sensor  1136  and a soil sensor  1137 , wherein the accelerometer  1133  collects acceleration data, wherein the sonic sensor  1135  collects the sonic data, wherein the PH sensor  1136  collects the PH data, wherein the soil sensor  1137  collects the soil data. As some kinds of the sensor has requirement of reach the outside of the data logger  10  to feel the condition of the environment. One skilled in the art will understand that it risks to expose the main board  11  to the harsh environment. Therefore the sensors preferred to be die in module. The pressure sensor  1131  of the sensor unit  113  is made packaged and ensured valid. And the data will be acquired by the acquisitor  50  to be profile like  FIG. 7  and  FIG. 8 . 
     The data acquisitor  50 , as shown in  FIG. 9  to  FIG. 11 , further comprises at least one seat  51  for placing the data logger  10 , a transmitting connector  52  set inside the seat  51  and an acquisition board  53  to acquire data recorded in the data logger  53  through the transmitting connector  52  and the connectors  1151  of the communication unit  115  of the data logger  10 . For further analyzing, the data acquisitor  50  comprises a transmitting medium  54  for transmitting data to a processing terminal, for example a computer or server. 
     An exemplary embodiment of the connection established between the data logger  10  and the data acquisitor  50 . Two or more the transmitting connector  52  mounted in the seat  51 , are soldered or plugged into the interface on the acquisition board  53  of the data acquisitor  50 . These transmitting connector  52  are used for data transmitting and receiving. When the data logger  10  is placed in the seat  51 , the two or more the connectors  1151  on the data logger  10  face down towards the transmitting connector  52 . By pushing the data logger  10  inside the ball seat tightly, the connectors  1151  have contacts with the transmitting connector  52 . Therefore, a wired connection between the data logger  10  and the computer is established through the data acquisitor  50 . By sending proper commands from the main computer side, data stored in the data logger  10  can be transmitted and finally downloaded to the computer. 
     Another embodiment of linking the data logger  10  and the data acquisitor  50  is wireless connection. there are no pins installed in the ball seat. Antennas may be installed in the data logger  10  and the data acquisitor  50  for enhance wireless connection. The data stored in the data logger  10  is wirelessly transmitted to the data acquisitor  50 , and then to the computer through the cable. 
     The preferred embodiment of the present invention further provides a method of manufacturing the data logger  10  and a mould  70  for packaging the data logger  10 , as shown in  FIG. 14  to  FIG. 18 . The mould  70  is shaped in cap which suitable for placing the main board  11  inside. 
     The method of manufacturing the data logger  10  comprises following steps: 
     Assembly the main board  11  of the data logger  10 ; 
     Placing the main board  11  in the mould  70 ; 
     Pouring the material of the jacketing  12  between the main board  11  and the mould  70 ; 
     Solidifying the jacketing  12  and demoulding; 
     Placing the mould  70  on the other side of the main board  11 ; 
     Pouring the material of the jacketing  12  between the main board  11  and the mould  70 ; and 
     Solidifying the jacketing  12  and demoulding to be the data logger  10 . 
     The material of the jacketing  12  is preferably to be thermosetting adhesive, opticalsetting adhesive and so on. One of the material of the jacketing  12  is polymer epoxy resin which can be solid in common temperature. 
     Further, during pouring the material of the jacketing  12  further put density control materials inside, such as low density epoxy foam, aerogel, glass microsphere and so on, which is about 0.4-0.8 g/cc. Therefore the density of the data logger  10  is adjustable to be near to the density of the drilling fluid and the center of gravity is steady. As in  FIG. 16 , direction M is the opposite of the gravity that the suffered. 
     The method of manufacturing the by the shell  13 , after the step of solidifying the jacketing  12  and demoulding to be the data logger  10 , further comprises following steps: 
     Placing the main board  11  in the mould  70 ; 
     Pouring the material of the shell  13  between the main board  11  and the mould  70 ; and 
     Solidifying the shell  13  and demoulding. 
     Furthermore, as the sensor unit  113  needed to be touched to the environment, like the sensing channel  11314  of the pressure sensor, it is worth to mention that the shape of the mould  70  needs to be matched to the sensing channel  11314 . As shown in  FIG. 18 , the method of manufacturing the data logger  10  is illustrated. The tube which formed the sensing channel  11314  is placed at the sensing area  113111  of the pressure sensor chip  11311  advanced. While pouring the material of the jacketing  12  between the main board  11  and the mould  70 , the sensing channel  11314  can be formed integrated by the jacketing  12 . And it is worth to mention that the tube can be demould or can be leave inside the as long as the sensing area  113111  is ensured. Also, the sensing channel  11314  can be formed by the sealing layer  11313  and then enhance by the jacketing  12 . And the sensing channel  11314  can be formed only by the sealing layer  11313  which also works to keep the sensing area  113111  functional. In  FIG. 18 , the method of the manufacturing of the sensing channel  11314  is disclosed which teaches other kinds of sensor to form channels for sensing the environment as required. 
     One skilled in the art will understand that the embodiment of the present invention as shown in the drawings and described above is exemplary only and not intended to be limiting. 
     It will thus be seen that the objects of the present invention have been fully and effectively accomplished. The embodiments have been shown and described for the purposes of illustrating the functional and structural principles of the present invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.