# Research on Key Technologies of 260 \({}^{\circ}\)C/210 MPa Ultra-Deep Logging Equipment
## 2 Current Status of the Key Technologies for Ultra-Deep Well Logging Equipment  
Leveraging advanced chip and detector manufacturing technologies, Schlumberger, Halliburton, and other logging companies' well logging technologies and equipment lead the field in high-temperature and high-pressure applications [6]. Schlumberger's high-temperature and high-pressure slim-hole Qstring series has an outer diameter of 76 mm, with temperature and pressure ratings reaching up to 260 \({}^{\circ}\)C and 206.9 MPa. This series is complemented by the Tufline30000 high-strength high-temperature cable system, which has a maximum tensile strength of 30,000 pounds (lbs) and can withstand temperatures up to 232 \({}^{\circ}\)C for 24 h. Additionally, it features an ultra-strong cable drum capable of holding 131,000 m of cable, all of which are custom-made for overseas ultra-deepwater projects. Halliburton's Hostile slim-hole logging series includes tools with outer diameters of 70 mm and 79.4 mm, with maximum temperature and pressure ratings of 260 \({}^{\circ}\)C and 137.9-206.8 MPa, respectively.  
China's ultra-high-temperature and high-pressure well logging services largely rely on imported instruments, which, due to cost considerations, are only used in a few exploratory wells and key development wells, failing to meet the production needs of numerous domestic development wells. In response to this situation, several Chinese companies have started developing high-temperature and high-pressure slim-hole instruments. CNPC has independently developed the \"230 \({}^{\circ}\)C High-Temperature High-Pressure Slimhole Logging Series\" based on conventional instruments. This series overcomes technological bottlenecks such as high-temperature high-integration design based on MCM circuits, high-temperature pressure-bearing structure design and processes, and slim-hole instrument environmental calibration. The resulting high-temperature high-pressure slim-hole (\(\Phi\)76 mm) logging equipment can withstand temperatures and pressures up to 230 \({}^{\circ}\)C and 170 MPa, suitable for minimum borehole diameters of 100 mm. In August 2024, this series successfully completed the fourth phase of the Shendi Ta Ke 1 well project, fully validating the stability and reliability of 13,000 m long cable remote transmission communication, ground collection and downhole instruments, and ultra-deep well logging power skids, setting an Asian record with a logging depth of 9889.63 m. CNOOC's ESCOOL ultra-high-temperature logging system (ESCOOL system) has capabilities for cable logging at 235 \({}^{\circ}\)C/175 MPa and imaging and coring sampling at 205 \({}^{\circ}\)C/140 MPa. To date, it has completed logging operations in over 260 wells, with a maximum pressure of 163 MPa, highest temperature of 206 \({}^{\circ}\)C, and deepest well depth of 8835 m, covering full-size operations from surface large boreholes to ultra-deep slim holes. The high-temperature high-pressure series instruments produced by Jereb have a maximum outer diameter of 80 mm and have completed over 180 ultra-deep well operations exceeding 8000 m, with the highest records being a maximum vertical well depth of 9300 m, highest well temperature of 191 \({}^{\circ}\)C, and maximum pressure of 179 MPa.  
To better ensure the quality of ultra-deep well logging tasks, CNPC Logging is leveraging its existing CPLog rapid and imaging series instruments to continuously tackle the core key technologies. These include 260 \({}^{\circ}\)C/210 MPa logging sensors and mechanical structures, fully enclosed compact 260 \({}^{\circ}\)C circuit systems, 13,000 m cable ultra-deep well communication and storage, ultra-deep well logging borehole correction processing, and fine interpretation and evaluation. The aim is to quickly develop 260 \({}^{\circ}\)C/210 MPa ultra-deep well logging technology equipment to achieve comprehensive and accurate data collection in ultra-high-temperature and high-pressure wells.