Analysis of water invasion effect and development scheme design for deep water HHT gas reservoir: A case study of LS25 gas field

Abstract

Based on the South China Sea deepwater high temperature and high pressure gas reservoir LS25 gas field, 3D geological model and a numerical reservoir model of LS25 gas field are established. Through numerical simulation of gas reservoir production, quantitative analysis of water invasion characteristics of 11 wells has been completed. The whole process of water invasion in space is as follows: bottom water conies in the early stage, forming water cone shape, the scale of the water body to the ridge increases, and the horizontal section completely emerges. Through comparative study, it is concluded that the combined water control technology of variable density screen pipe has the best water control effect. According to the prediction and analysis of the final production plan of variable density technology, it can prolong the water-free gas production period of the gas reservoir by 0.7 years, prolong the total production time by 1.9 years, increase the gas production by 1.9×108m3, and increase the recovery factor by 10.5% compared with that without water control measures. The research results are aimed to establish an optimal water control development model for buried hill gas reservoirs, and provide a good technical support for reasonable and scientific water control research of horizontal wells in offshore buried hill fractured gas reservoirs.