强水驱稠油油藏水平井初期产能主控因素研究

Study on Initial Productivity Control Factors of Horizontal Wells in Heavy Oil Reservoirs with Strong Water Flooding

南海东部P油田属于强水驱稠油油藏,以水平井开发为主,油井投产初期具有产量高、低含水和低压差的开发特点。考虑海上油田井下作业成本较高,油井初期产油量对开发效果及措施经济性影响较大,因此以P油田27口开发井实际生产动态资料为基础,采用灰色关联分析与油藏数值模拟方法相结合,对强水驱稠油油藏水平井初期产油量的主控因素开展定量化研究,明确其关联强弱与变化规律。结果表明,强水驱稠油油藏水平井初期产油量影响因素由强到弱依次为:水平段长度、渗透率、避水高度、水油砂厚比、原油黏度和隔夹层分布,主控因素为水平段长度、渗透率和避水高度。水平井初产油随着渗透率、水平段长度和避水高度的增大而增大,但增加幅度趋于变缓;当水平段长度超过800m、避水高度大于15m,地质油藏参数变化对油井初期产油量影响的敏感性明显减弱。

Oilfield P in the east of the South China Sea is a heavy oil reservoir developed by strong water flooding of horizontal wells mainly.The oil wells have the characteristics of high production,low water cut and low pressure difference at the initial stage of production.Considering the high cost of downhole operation in offshore oilfields,the initial production of oil wells has a great impact on development results and the econo-my of measures.Therefore,based on the actual production dynamic data of 27 development wells in Oilfield P,a quantitative study on the main controlling factors of initial oil production of horizontal wells in heavy oil reservoirs with strong water flooding is carried out by combining gray correlation analysis and reservoir nu-merical simulation to clarify the correlation strength and change rule.The results show that the initial oil pro-duction of horizontal wells in heavy oil reservoirs with strong water flooding is influenced by horizontal sec-tion length,permeability,water avoidance height,water-oil sand thickness ratio,oil viscosity and interlayer distribution in order from strong to weak,and the main factors are horizontal section length,permeability and water avoidance height.The initial oil production of horizontal wells increases with the increase of permeabili-ty,length of horizontal section and water avoidance height,but the increase rate tends to be slow.When the length of the horizontal section is more than 800m and the height of water avoidance is more than 15m,the sensitivity of the influence of geological reservoir parameters on the initial oil production of the wells is ob-viously weakened.