# Research on Key Technologies of 260 \({}^{\circ}\)C/210 MPa Ultra-Deep Logging Equipment
## 3 Research on Key Technologies of Ultra-High-Temperature and High-Pressure Logging
### Large borehole Data Processing  
In logging environments, factors such as borehole diameter, mud density and salinity, mud cake, borehole roughness, mud invasion zones, formation temperature and pressure, the surrounding rock, and instrument outer diameter and clearance can inevitably influence various logging curves. Especially in the cases of poor borehole and mud quality, these non-formation factors can cause severe distortion in the logging curves. In ultra-deep wells, the impact of these non-formation factors is even more pronounced due to the multiple openings, particularly when there are large boreholes in the first or second openings. Therefore, it is necessary to establish a comprehensive set of borehole environment correction charts for the instrument series to ensure the accuracy of the measurement data. The process and method for calculating reservoir parameters in ultra-deep wells are similar to those for conventional reservoirs, with differences mainly in two areas: the calibration of logging by rock physics experiments and the evaluation of reservoir effectiveness and accurate fluid identification under deep high-temperature and high-pressure conditions. For the former, the measurement parameters under confining pressure conditions should be used to calibrate the logging curves. For the latter, an improved evaluation system is needed. Through in-depth research on deep high-temperature and high-pressure reservoirs, the currently adopted evaluation system (as shown in Figure 14) includes the following:  
1. Calculation of the reservoir parameters based on conventional logging data. 2. Evaluation of reservoir levels near the borehole using imaging logging. 3. Identification and evaluation of fractures, the analysis of formation anisotropy, and provision of engineering data using array sonic data. 4. Evaluation of fracture development near the borehole using far-field sonic detection. Among them, 3 cm represents the radial detection depth of the electric imaging instrument, 1.9 m represents the radial detection depth of the array lateral instrument, 3 m represents the radial detection depth of the array acoustic instrument, and 3-40 m represents the radial detection depth of the remote detection of acoustic reflection imaging instrument. The black, green, blue, and red lines in the third column represent the resistivity  
Figure 14: Evaluation system for the effectiveness of dual-porosity medium reservoirs and accurate fluid identification under deep high-temperature and high-pressure conditions. curves HALT1, HALT2, HALT3, and HALT4, respectively, corresponding to different radial detection depths in array lateral logging. Figure 15 shows the application results of the above evaluation system in the Dagang XX well. The well was drilled to a depth of XX70 m with a bottom hole temperature of 216 \({}^{\circ}\)C. After successfully obtaining the data, reservoir effectiveness evaluation and fluid identification were carried out. Firstly, the porosity and resistivity spectra derived from micro-resistivity imaging logging data were inverted to obtain the vertical distribution of porosity near the wellbore (Track 10). Vertically, Layer 213 exhibits relatively developed porosity. Subsequently, conventional curves were used to calculate the lithology profile (Track 8) and porosity values (yellow-filled section in Track 7) near the wellbore, while resistivity invasion relationship information (Track 6) was also obtained. Layer 213 remains a relatively high-quality reservoir within this interval. Then, the bulk modulus and Poisson's ratio near the wellbore, calculated from the array acoustic data, overlapped (Tracks 11 and 12), revealing gas-bearing responses in Layers 213, 214, 216, and 218, with Layer 213 showing the most significant gas-bearing response. Finally, fractures near the wellbore were detected using far-detection techniques, revealing a set of fractures near Layer 216, approximately 28-30 m away from the wellbore.