应用水平井技术改善稠油油藏开发效果

Application of horizontal well technology in improving development efficiency of heavy oil reservoir

高246块莲花油层属于厚层块状砂砾岩底水稠油油藏,已利用直井开发30a,受油水流度比高、储层非均质性强及出砂、出底水等因素制约,已进入高含水低速采油阶段。综合含水率为71.3%,采油速度为0.18%,且水窜逐年加剧,含水率上升速度高达43%,半数油井因高含水率而关井,区块年产油量指数下滑,达不到标定采收率。针对开发存在的这些问题,以精细油藏描述为基础,以剩余油潜力评价为保障,以水平井技术为依托,进行二次开发研究,部署并实施18口水平井,取得了显著效果,油田采油速度上升到0.35%,综合含水率下降到56%,预计可提高采收率3.4%。

The Lianhua Formation reservoir of Block Gao 246 is the heavy oil reservoir with thick massive glutenite and bottom water, which has been developed by vertical wells for 30 years. The reservoir has been in high water cut and low production rate period due to the high oil-water viscosity ratio, severe heterogeneity, sand entry and bottom water entry. The comprehensive water cut and production rate reach 71.3% and 0.18% respectively. Water breakthrough gets worse every year and water cut rises in a rate of 43%. Almost half of production wells are shutdown due to high water cut. Calibrated production rate can not be reached due to the decreasing of productivity index. In order to solve the problems during oil production, this paper studies the second development plan of high water cut reservoir by horizontal well based on the fine reservoir description and residual oil potential assessment. Eighteen horizontal wells are deployed with a obvious production enhancing effect. Production rate rises to 0.35% and water cut drops to 56%. Recovery rate is expected to be enhanced by 3.4%.