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Special Detection

Sinopec PG gasfield, located at Xuanhan area, Dazhou city, Sichuan, is one of the main gas source of Sichuan to East Gas Pipeline Project and also a world famous high acid gasfield. Its average 8%CO2content and 15%H2S lead to severe producing condition. As an important well control equipment, Xmas tree counts a lot in grasping and monitoring wellhead condition. Since brought into production two years ago, PG gasfield couldn’t have implemented detection to Xmas trees owning to limitation of domestic detection technology. In July 2011, supported by technology demonstration and project approval, Xmas tree ultrasonic self-correcting 3D multi-point detection and interpretation system imported by UP from Canada Infomax Company was achieving comprehensive detection against 51 wells’ Xmas trees on PG gasfield. A single well database was also established. Altogether 8 abnormal wells were found out, here we pick out the P #302-2 well as a typical case.

On the P #302-2 well, there is a 70 Mpa FMC integral Xmas tree. Three key parts were choosen to be detected thoroughly. (see detecting parts in picture below)

Onsite Detection Schematic Diagram

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The production quota of P #302-3 well is 90*104 m³/d and the total output reaches 75932*104 m³, its a high-yielding well. Some abnormal points were found out at No.1 detected part during its Xmas trees detection.

The entire No.1 detected part present uneven thinning and the avrage thinness is 0.010±0.005mm;  C-4 (X: 65Y: 82) is abnormal: image shows abnormal transverse cracks, the central abnormality degree is 0.23mm and the figure is 3.32*1.59mm; testing waveform shows that the border noise points of abnormal parts is smooth and the middle noise points become bigger. In conclusion, it is interpreted as slight abnormality. 


Inner Wall Image 


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 3D Stereogram     

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  3D Color Temperature Diagram

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Abnormal Points Oscillogram

P #302-3 Well Part 1 Image