Cementing technology for casing damage remediation of Well Yuetan-1 in the offshore area of Liaodong Bay

Well Yuetan-1 is a high-pressure gas well in the offshore area of Liaodong Bay. During cementing of the third casing section, the Ø244.5 mm casing string was damaged and fractured at 1 238 m, which led to the sealing loss across high-pressure gas reservoir intervals from 2 626 m to 3 690 m. In order to effectively restore well integrity and meet the drilling requirements of the fourth casing section, a cement slurry system with low water loss, low flow resistance, high thixotropy and high channeling prevention capacity and thus suitable for cement squeezing operations was developed, according to the inspection results of the downhole cable camera and the downhole complex situation of Well Yuetan-1. A casing damage remedial cementing technology for high-pressure gas wells was formed, in which casing damage cracks are sealed by choke cement squeeze, and the high-pressure gas reservoirs are isolated by retainer cement squeezing and intermittent cement squeezing cement. After the treatment, the casing string was pressure-tested to 20 MPa with no pressure drop and no annular pressure, and the high-pressure gas reservoir was well sealed. The daily gas production in the trial production reached 19 000 m³/d. This technology and field application provide technical references for the treatment of similar complexities such as casing damage.