Research And Application On The Theory And Method Of AIL Array Induction Logging

Array induction logging as an important resistivity logging method could exactly measure the undisturbed zone resistivity and reservoirs evaluation of oil and gas. In this dissertation, based on the previous research findings, the four classical geometrical factors theory as Doll, Gianzero, Moran and Born have been discussed the characteristics and limitations in detail by the electromagnetic field and the differential form Maxwell's equations. Then AIL logging characteristics, tool design and implementation, logging data processing and interpretation are presented.Based on study of Schlumberger, Baker atlas and Halliburton's tools in detail, AIL logging parameter of design and implementation has been presented. Subarray is the fundamental unit of the coil array. This dissertation takes examples for two cases of four-coil subarray and three-coil subarray to study on the subarray structure, frequency choice, design essential and geometry characteristic. The geometric factor characteristic of subarray has been discussed on the coil arrange. The rules has been defined about frequency choice and tool design essential. The technical criterion has been proposed on the geometry characteristic.AIL array logging have ten coils from L1 to L10 based on three-coil subarray of two-coil transmitting and one coil receiving. It has four three-coil subarray with radial investigation depth 0.72m, 1.23m, 1.82m and 2.97m. The active and reactive signal components have been synchronously recorded, and eight resistivity curves could be recorded too. Study on the geometric factor characteristic to form charts of radial response and vertical response based on coil system parameter. The emendation chart has been planned according to the skin effect and borehole correction. Study on the tool calibration with tool calibration principle, method and parameter. Signal processing and method application have been researched on the deconvolution filtering, signal composition and background conductivity computing. Based on AIL logging coil system, numerical simulation of response on theborehole and mud resistivity, surrounding formation and formation model are presented.Total circuit scheme and time sequence of tool design and implementation have been designed on the AIL logging characteristic. The design and analysis for circuit unit have been carry out on the several units such as main control circuit, signal phantom circuit, signal control circuit, amplifier circuit, A/D circuit, transmitter drive circuit and power circuit.AIL logging have been applied on the oilfield with full test and a lot of data to be recorded successful. This logging data have been researched by data processing and interpretation. By the comparative analysis, outputting results present several cases in detail, such as the resistivity sensitive, oil and water layer identifiable, quantitative interpretation, invasion characteristics of mud filtrate, dual-trace phenomena and thin-layer identification.