Pipeline Repair and Hot Tapping Project for Defective Girth Weld Replacement at K2+230m of Riyi Pipeline

Project Overview:

The Riyi Crude Oil Pipeline spans 390km, starting from Rizhao City, Shandong Province, passing through Lianyungang, Suqian, and Huaian in Jiangsu Province, and Chuzhou in Anhui Province, before terminating at the Yizheng Terminal in Yangzhou, Jiangsu.

Key Pipeline Specifications:

• Design Pressure: 8.5 MPa
• Diameter: 914mm
• Material: L450 (X65) straight/seam-welded steel pipe
• Wall Thickness: 12.5mm / 15.9mm / 17.5mm
• Transported Medium: Crude oil
• Operating Pressure: 3.5–5.9 MPa

Pipeline Repair Requirement:
The Rizhao Section of the pipeline is managed by PipeChina Shandong Company (Rizhao Operating Area). Following the 2024 Girth Weld Excavation & Inspection Plan, two high-consequence area (HCA) welds between Rizhao Oil Depot and Valve Station #1 were excavated on March 26. PAUT & TOFD non-destructive testing (NDT) confirmed defective welds.

On April 6, the China Special Equipment Inspection & Research Institute (CSEI) conducted a fitness-for-service (FFS) assessment, concluding that the welds were unacceptable for continued operation.

Challenges:

• The defective section is located in the pipe corridor zone of Lanshan District, Rizhao.
• The weld is adjacent to the parallel Kejia Crude Oil Pipeline, making B-type sleeve welding impossible.
• To relieve stress, 25m of pipeline on both sides was manually excavated, but the defective weld remained too close to the Kejia pipeline.

Scope of Work:

• DN914 Double Block & Bleed (DBB) Isolation

Construction Period:

May 6, 2024 – June 6, 2024

Location:

Rizhao, Shandong Province, China