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Brief introduction of Sitan engineering logging instruments
- Sep 11, 2018 -

In the process of oilfield exploration and development, logging is an important means to determine and evaluate oil and gas layers, and is also an important means to solve a series of geological problems. A series of well logging methods that analyze and evaluate cementing quality, perforation conditions, borehole conditions, reservoir operations, and stimulation measures by detecting casing, cement sheath, and formations are called engineering logging. For a variety of methods in engineering logging technology, SITAN has designed a series of logging instruments, such as Multi Finger Caliper(MFC), Magnetic Thickness Tool (MTT), Magnetic Thickness Detector (MTD), Radial Bond Tool(RBT).

The multi-finger caliper (also called as Multifinger Imaging Tool (MIT)) is used to determine the inner diameter of the casing, the depth of the perforation, and the depth of the coupling to detect the quality of the metal casing. These instruments include X-Y caliper, 24-arm caliper, 40-arm caliper, and 60-arm caliper. The motor controls the opening and retraction of the detecting arm, and the movement of the mechanical detecting arm along the well wall causes a change in the output signal of the displacement sensor. After signal processing, a stereoscopic image is finally obtained by means of the imaging software. Analyze images and test data to determine (identify) deformation, misalignment, bending, perforations, cracks and contamination of the casing, and corrosion or defects outside the casing. It also accurately measures lateral and longitudinal cracks of the casing and the thickness of the casing.

The magnetic logging tool is used to determine the damage, corrosion, and penetration of the casing. It mainly includes Magnetic Thickness Tool (MTT) and Magnetic Thickness Detector (MTD). The sensor array of the Magnetic Thickness Tool (MTT) is composed of 16 (12) independent sensors, each of which can measure a wall thickness curve of the casing. Combined with the measurement of the multi-arm caliper, the damage of the outer wall or the damage of the inner wall can be distinguished. The Magnetic Thickness Detector (MTD) uses the principle of electromagnetic induction to detect casing damage, such as thickness variation, corrosion, deformation and rupture, and can accurately indicate the structure of the downhole and the position of the tool, and can detect ferromagnetic substances outside the casing (such as casing centralizer , surface casing, etc.).

The Radial Bond Tool (RBT) is used for casing well cementing quality inspection, and the cement bond effect is checked by recorded sound amplitude, acoustic variable density and full wave train information. The acoustic pulse generated by the acoustic transducer in the instrument radiates in all directions, scans the well wall, the sector receiver receives the echo signal, and then obtains the cement distribution profile through the graphical processing. The cement bond logging reflects the condition of the first cementing surface, and identifies the location, size and distribution of the channel and the hole existing in the first interface; the variable density logging complements the analysis of the first cementing surface, and the top of cement and the second cementing interface can be accurately evaluated.