Corrosion resistance technology for rod and tube in drainage wells in South Yanchuan coalbed methane field

In view of pump inspection caused by corrosion to rod and tube in some drainage wells in South Yanchuan coalbed methane field, research has been conducted on corrosion resistance technology for drainage wells. The gas components from drainage wells and the components of produced formation water are analyzed; research has been done on the corrosion law of various materials in different water type conditions, and based on this, the main causes have been identified for rod and tube corrosion in South Yanchuan Block, and two corrosion inhibitors are selected: KD-H03-1# and KD-H03-2#. This technology was tested on five wells, including Well Y3-40-24U; After treatment, the daily fluid production of drainage wells was 2.8 m3 and daily gas production was 585.29 m3. The result shows that addition of KD-H03-1# inhibitor to CaCl2 water type can delay corrosion to downhole rod, tubing and pump and can extend the pump inspection period, providing new technical support for continuous drainage and production of drainage wells in South Yanchuan Block.