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Bao Dezhou Zhang Xinyun
(China Petroleum Logging company, Ltd.)
ABSTRACT: Imaging logging technology plays a key role in complex and heterogeneous reservoir exploration. In the imaging log families, the array induction imaging log has outstanding effects in the comprehensive interpretation of oil zones featured with low resistivity, which effectively determines the oil saturation of reservoir, and quantitatively describes the invasion profile of drilling fluid, thus catches more and more log interpreters’eye.
This paper briefly introduces the technological and methodological features of a newly developed array induction imaging logging tool (MIT), and outlines the digital composite technology, borehole environmental correction and field tests of the tool. Based on comparative analysis with the same kind tools of other companies in numerous wells in northern
Key words: MIT array introduction, imaging logging, technological structure, field test, applicative analysis
INTRODUCTION
With the development of computer technology, modeling focused introduction logging tool is evolving forward to digitalization and array. In the 90s of 20th century, several world class logging companies introduced array introduction imaging logging tools one after another. The new technology greatly enhanced traditional introduction logging tool, not only improving the vertical resolution and the quantitative description of formation radial heterogeneous invasion, but also simplifying coil manufacturing technique, broadening the tool dynamic range, meanwhile improving logging efficiency[1].
Array introduction imaging logging tool is a new generation of digital and array logging tool, which have the detector with array coil system and adopt multiple frequencies for real time data acquisition. The measurement provides the real and imaginary components of formation conductivity which is processed to obtain the resistivity curves with multiple vertical resolutions and investigation depths. The technology is mainly applied to describe formation bedding and mud invasion, delineate permeable oil/gas layer, compute formation resistivity for oil saturation computation, provide visual 2 dimensional image for the comprehensive interpretation of complex and heterogeneous formation.
During the ninth five year plan, China National Petroleum Corporation (CNPC) organized and conducted the research and development of the array induction imaging logging technology, and the developed array introduction imaging logging tool (MIT) was tested in oil fields. This paper discusses the features of the MIT method and technological structure, and introduces the test and application of MIT, and analyzes the points for attention in the data processing and interpretation in hostile borehole situations
MIT TECHNOLOGICAL STRUCTURE
The MIT system consists of surface processing modulus, software and downhole tool. The modulus include telemetry module and data decoding module, and the software includes field logging software, composition software, and borehole correction, calibration and image processing software. The downhole tools include CTS telemetry sub, power sub, data acquisition sub, prime amplifier sub, coil system sub, pressure balance sub, transmitter circuit sub. The tool specification is as follow:
measurement range 0.1-2000 ohmm