| Along with the upgrading of the level of industrialization and rapid economy, theenergy problem has become the important restriction factor of economic developmentin China, Statistics show that China’s oil demand will reach to540million tons to2015, and external dependency also will arise to more than60%. In order to deal withthe energy shortage problem, we need to accelerate the pace of oil and gas resourcesexploration and expand energy exploration areas, and the exploration area is large andlow degree in China’s Midwest basin piedmont zone, but the exploration potential ishuge, Therefore, the oil and gas exploration extends to complex mountainous regionwill be the more effective solutions.As the main method of current oil and gas exploration, the seismic explorationhave made more fruitful results in the long-term practice process, especiallycontinuous increase of land seismic exploration equipment performance in a largescale, which make the seismic exploration construction wiring more flexible, andexploration efficiency has been improved continuously. In complex mountainousregion, however, because of the complexity of the surface topography condition andunderground structure, as well as the particularity of geographic environment, whichmakes it is very difficult to acquired the seismic data, and because of these it proposedsevere challenges to progress and development of seismic exploration technology andequipment. Especially proposing some new requirements to those key technologyincluding the calability and portability of the equipment, the randomness anduncertainty to layout three-component geophones, the overall compatibility of thedevice and its laid flexibility under complicated conditions, time synchronization inadverse environments and field quality control of seismic data. The primary problem of seismic exploration is the science of seismic data acquisition problems. Althoughmulti-wave seismic exploration method still has a lot of problems need to solve intechnically, but due to the cost of a single input can get abundant full waveinformation, so it will become a trend that the longitudinal wave and converted wavejoint exploration instead of pure longitudinal wave exploration, especially itsoperability and low cost characteristics in the field, which is more suitable forcomplex mountainous seismic exploration.For the special requirements of the mountain exploration, this article relies on the"the development of multi-wave and broadband seismic data acquisition system undercomplicated mountainous condition which belongs to important scientific instrumentsequipment developed special for NSFC, and the "nuclear geophysical prospectingtechnology instrument development and application research" belonging to theNational Science Fund for Distinguished Young Scholar. Improving the quality ofseismic data acquisition and the exploration efficiency as the springboard, anddominated by multi-wave seismic exploration method, launching several research thatmulti-functional sensor integrating the gesture detection, portable self-containedsignal acquisition station, adaptive data transmission network and control acquisitionsoftware and so on. There are the following key technologies and innovativeachievements in this paper:(1) Gesture detection for multi-functional gepohone. Assembling the orthogonalthree-component geophone with high sensitivity of MEMS accelerometer, andintegrating high precision gyroscope, electronic compass and angle sensors,respectively for acquire the weak seismic signals, the orientation of geophone and tiltangle and other relevant information, in order to adjust the detector of eachcomponent to receive various seismic composition more effectively, and it isadvantage to implement the amendment of the each components of the detectorazimuth deviation. It replaced the traditional energy approximation estimation methodwhich exist the inherent errors. Its azimuth information can offer a good support forsensor layout of azimuth adjustment in the construction processed. Ensure theconsistency that the shot point of seismic source and acceptance point.(2) Signal acquisition station development based on FPGA and IP soft-core. Thelogical sequence of the multi-channel ADC (A/D converter) is controlled by hardware,using the double buffer technology to realize the switch type storage of data toeliminate non-uniform use problem which is caused by the storage time delay caused,and build strict parallel acquisition data channels. Completely based on IP core development of multi-tasking driving, which make the system configuration andadjust more flexible, and enhance the integration degree of the machine greatly, thusimprove the portability of the acquisition station.The system was based on FPGA platform, and multi-functional IP soft-core drivemode, it improves integration degree of the acquisition system from the aspects ofhardware, reduce the size of equipment. Using a single signal collection stationconnect four-way three-component geophone, and convenient to the expansion of theacquisition channel and meet the demand of cutting, at the same time, cooperate withdata transmission method of wire and wireless hybrid network, and ensures the systemcan meet with the need of field exploration,"adjust measures to local conditions " toselect reasonable observation system, so as to improve the quality of seismic dataacquisition and the efficiency of exploration.(3) Upgrade of the system dynamic range and low noise processing. Achievingmicrovolt level signal response level to improve the input dynamic range adoptingfixed-gain amplifier with very low offset voltage and cascading programmableamplifier. Clean and stable power supply system is the assurance of low noise, inorder to balance the power efficiency, using LC filter and LDO ripple suppressioncircuit to processing power ripple and noise, thereby reducing the system noise andimprove the fidelity of the acquisition system.(4) Improve the acquisition system compatibility and adaptability. Achieveprime amplification of the system, filtering function parameters could be configureddynamically. Therefore it is compatible to a variety of detectors and explorationmethods, at the same time, increasing system’s bandwidth, it eliminate aliasing anddistortion effects. The system adopts the mode of data transmission of wired andwireless Ethernet hybrid network, which make the construction and wiring moreflexible.(5) The development of control acquisition software based on QT platform andOpenGL. Development of graphical control platform which is easy to operate andintegrated control and transmission protocol, pretreatment and analysis,2d waveformdisplay and switch quickly,3d gesture show and so on. Enhance the readability of thewaveform based on rectangle filling technology, and process the phenomenon oftwo-dimensional waveform display screen flicker automatically using the QWidgetwhich is based on double buffer technique. For the3D display, it is based on the3dframe of OpenGL, coordinating with custom three-dimensional model of the detector,and capturing detector’s gesture real-time. Overall, the paper makes use of independent acquisition station, using the designidea of distributed remote telemetry collecting to building seismic data acquisitionnetwork, integrating three-component MEMS accelerometer sensors, electroniccompass, gyroscope, angle sensors to make up multi-functional detector, designingmulti-channel signal conditioning module which can be configured, and improve thesystem dynamic range and bandwidth, cooperating with parallel acquisitiontechnology to form the strict parallel acquisition circuit which can extensible and becutting, and making the acquisition station can be compatible with a variety ofdetector. At the same time, to use the Ethernet transmission technology of wire andwireless hybrid network to enhance the adaptability of system under variouscomplicated construction conditions, and to improve seismic data transmission ofreal-time and anti-interference ability, from the point of hardware to improve thequality of seismic data acquisition. Thus enhance the adaptability of seismicexploration equipment in complex mountainous region construction, and construct theobservation system flexibly, to further improve the quality of seismic data acquisitionand exploration efficiency. |
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