Volume 63

A Novel Atmospheric-Pressure, Low-Temperature Evaluation Method for Natural Gas Hydrate Dissociation Inhibitors Utilizing Cyclopentane Hydrate Haozhe Chen, Lili Yang, Xuanyu Long, Limin Zhu, Sanpeng Huang

Abstract

During natural gas hydrate (NGH) drilling and production, changes in reservoir temperature and pressure conditions, along with heat generated by drilling operations, can lead to partial or even uncontrolled hydrate dissociation. This phenomenon increases the risk of wellbore instability and jeopardizes drilling efficiency and safety. Hydrate dissociation inhibitors have thus emerged as critical components for stabilizing hydrate-bearing formations and mitigating drilling risks, thereby supporting efficient NGH extraction. However, current evaluation methods for NGH inhibitors predominantly focus on inhibiting hydrate formation, with relatively limited research addressing performance assessment of dissociation inhibitors. Based on a comprehensive literature review, this study first demonstrates the feasibility of using cyclopentane hydrate as a substitute for methane hydrate in evaluating dissociation inhibitor performance. An experimental protocol was designed accordingly to assess inhibitor efficacy using cyclopentane hydrate. Under this constructed evaluation framework, the equilibrium temperature of cyclopentane hydrate was measured at 6.73°C, and 0.7% lecithin solution effectively delayed dissociation for 53 minutes. These results validate the practicality and reliability of the proposed assessment methodology.

Keywords cyclopentane hydrate, dissociation inhibitor, inhibitor evaluation, lecithin