11 / 2021-08-15 19:20:56

Study on depressurization production of unconsolidated hydrate formation considering geomechanics

natural gas hydrate,unconsolidated formation,formation subsidence,numerical simulation,safe and effective production

Marine hydrates are mostly buried in unconsolidated or weakly consolidated formation with poor cementation and low strength. Therefore, the decomposition of hydrates during production may lead to large subsidence of formation, then production has to be stopped. In this paper, numerical model of unconsolidated hydrate formation considering geomechanics is established and depressurization production process is simulated. Through analyzing the influence of formation parameters (such as hydrate saturation, formation porosity and buried depth) on gas production, the sensitive factors of unconsolidated hydrate production are obtained. After that, horizontal wells and vertical wells with different production parameters are simulated, and results are compared with that of consolidated hydrate formation. Aiming at reasonable formation subsidence, safe and effective production methods for unconsolidated hydrate formation with different parameters are determined. This work is an in-depth investigation of depressurization production of unconsolidated hydrate formation, which has certain guiding significance to field production.