Papers by Keyword: Well Logging

Abstract: Designed a high rate data transmission system based on OFDM for well logging. The system used time domain equalization and frequency domain equalization. The transmission data rate of the system can reach 1.2Mbps over 7440 meters CAMESA cable, and its BER is less than .

Abstract: Computerized well logging equipment plays an important role in petroleum exploration and production, and data acquisition system is the core of it. In order to improve the acquisition systems which are used in some oil fields in recent years, a new design of data acquisition system is introduced. The ARM embedded chip and the FPGA chip are the kernel chips of the data acquisition system, and the Ethernet is the communication medium between the cards of the data acquisition system and the host computer of the numerical controlled well logging system. This data acquisition system has more integrated level and communication speed higher than the others of same kind.

Abstract: In this study, the well logging response of CBM reservoir have been analyzed, and discussing the factors that affect the gas content of coal seam. The well logging technology has been employed in connection with log data and gas content. Take one oilfield’s well logging data for example, statistical analysis method and Langmuir equation method are selected to calculate the gas content of one coal seam, the two calculated results are basically the same, the highest value are about 26 cm³/g, is a high-yield coal seam.

Abstract: The most popular method to split the production is mainly based on permeability and effective thickness of reservoir. In this general method, the permeability comes from the well logging interpretation. But this permeability can not reflect the flow characteristics of real fluid in the reservoir. In this paper, a new production split method is proposed considering the well logging method, the well test method and relative permeability curve. It is proved to be reliable and effective after cases study. It is worth to promote in oilfields.

Abstract: Improving log vertical resolution is the principal pathway to enhance identification capability for the thin-layers. This paper introduces the method which is based on the wavelet transform and the deconvolution to improve log resolution. First, gain the sub-band information on the different scales after logging curve is decomposed by wavelet. Then the detailed coefficients on the third scale are processed with deconvolution filtering, and the detailed coefficients on the first scale are dealt with threshold denoising. At last, reconstruct the logging curve whose resolution is improved. The processed results of two wells’ logs indicate that the log vertical resolution has been improved obviously using this method, which can satisfy the demands of thin-layer evaluation.

Abstract: The reasonable estimate of rock mechanics is extremely important to the design of hydraulic fracture, but the direct triaxial test is a high consumption of time and money. The relation between the dynamic rock mass parameters and the static ones could be used to establish a new method to assess rock mechanics. This new method which was composed by some formulations generated by the well logging data and the Hoek-Brown criterion with the iterative computation way could provide calculated GSI, Young modulus and Poisson ratio data. These data has a little deviation, less than 10% which can be acceptable in project scope, with triaxial test value of rock core. As a result, this method has been proved to be easy and credible to use.

Abstract: An impulse-based single-borehole radar prototype for well logging is presented. An armored multi-conductor well logging cable is used to connect subsurface sonde and surface equipment in the prototype which is well compatible with the other well logging instruments. The performance experiments of the prototype have been conducted in a test field. The results show that the prototype system is capable of detecting the target which is 8 meters away from the borehole.

Abstract: Fractured rocks are the main oil and gas exploration objects offshore in China in recent years, which include the fractured sandstone, carbonate, volcanic rock, coal methane bed, shale gas and so on. The accurate calculation of the rock mechanics parameters (elastic modulus and Poisson’s ratio) play remarkable role in petroleum engineering operations, such as borehole stability, mud density window determination, perforation, EOR, in-situ stress predication and so on. Now the applications show that the in-situ stress estimation based on the rock parameters obtained by acoustic logging is much different from the downhole measurement with wireline formation tester. The pore space of the fractured rock contains fracture and cave and it is different from sandstone. In the paper a novel method based on the effective media theory with well logging for the rock mechanics parameters calculation of the fractured rock is introduced, and some problems and potential application are also discussed.

Abstract: In exploration for natural gas hydrates, drilling, coring and well logging are the most important access to make deep understanding of the nature of hydrate reservoirs, besides the seismic prospecting methods. Because of the harsh conditions for hydrate stability and the complex of occurrence formations, the drilling and coring generally have a great difficulty and high cost. Therefore, the well logging becomes the priority method. The resistivity and sonic logging method, which were applied as the earliest logging method in the evaluation of hydrate reserviors, have been continuously applied ever since and the evaluation results derived from them have a relative accuracy and reliability. Other logging tools, such as borehole imaging, density, electromagnetic, nuclear magnetic resonance, etc. are also used to make integrated interpretation and evaluation for the hydrate reservoirs. Until now the applied porosity and hydrate saturation evaluation models are better suitable to the homogeneous reservoirs. However, they still need to be amended or improved for the anisotropism (e.g., fracture sediment) and shale-rich reservoirs. In addition, the external factors such as drilling fluid washout and invasion will also affect the well logging results. The combination of various well logging methods is an effective way to improve the accuracy of identification and quantification of hydrate reservoirs.

Abstract: The drilling mud invasion is a dynamic process varying with time and reveal the permeability or the relatively permeability of the formation saturated with fluid. The mud invasion profile denotes the water saturation change with the radial distance from the borehole wall. The logging with the shallow depth of investigation (DOI), such as density logging, neutron logging and shallow electrical logging, often detects the information of the flushed zone. We chose DOI logging to model the slope invasion profile with the hyperbolic secant function, and the calculated logging reading comparing from the real logging reading to optimize the invasion profile. The results show that the mud invasion profile and the invasion depth are strongly affected by porosity, where the invasion depth reduces with porosity adding.