Unblocking Process of Complex Sulfur-Iron Scale Blockage in Sulfur-Bearing Gas Wells and Its Mechanism

Yabo Lv; Jiaqiang Ou; Haoran Fu; Juan Li; Zhifeng Luo; Xiaodong Yang; Jinming Zhao; Tingting Yang

doi:10.1021/acsomega.3c04031

Unblocking Process of Complex Sulfur-Iron Scale Blockage in Sulfur-Bearing Gas Wells and Its Mechanism

ACS Omega. 2023 Oct 20;8(43):40242-40250. doi: 10.1021/acsomega.3c04031. eCollection 2023 Oct 31.

Authors

Yabo Lv¹, Jiaqiang Ou¹, Haoran Fu², Juan Li¹, Zhifeng Luo², Xiaodong Yang¹, Jinming Zhao², Tingting Yang²

Affiliations

¹ Central and Northern Sichuan Gas Production Management Office, PetroChina Southwest Oil and Gas Field Branch, Suining, Sichuan 629000, China.
² School of Petroleum and Natural Gas Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500, China.

Abstract

In this paper, through the establishment of a blockage analysis process, multistage weight loss method, and FT-IR, GC-MS, SEM, EDS, XRD and other characterization test means, it is clear that the scale sample is mainly organic material covered with complex and diverse sulfur and iron compounds, and the mechanism of sulfur-containing gas well blockage is revealed by tracing into the well material, formation minerals, acid gas corrosion, and other substances. Through the selection of chelating agent, cleaning agent, and acid concentration, as well as the optimization of different process parameters, the "dispersion-chelation-dissolution" composite unblocking technology is proposed, and a set of unblocking formula systems for complex sulfur and iron scale is clarified. Finally, XRD and SEM characterization tests of the scale samples before and after dissolution were conducted to study the declogging mechanism and confirm the acid-insoluble nature of FeS₂ and its stability in a weak acidic environment.