普通稠油油藏大井距蒸汽驱技术界限研究——以乐安油田草4块沙四段4砂层组为例

On the Technical Limits of Steam Flooding in Common with Large Well Spacing——By Taking Es44 of Block Cao 4 in Le'an Oilfield for Example

乐安油田草4块Es44(沙四段4砂层组)为弱边水普通稠油油藏,采用蒸汽吞吐开发,井距200m×283m,目前已进入多轮次吞吐阶段,面临周期产量递减快、压力下降快、采收率低等难题。为实现该块大幅度提高采收率,考虑经济效益,结合该块实际地质情况,通过油藏工程分析和数值模拟研究等手段,研究了该块在200m×283m大井距下实施蒸汽驱的可行性和大井距下蒸汽驱的见效时间,明确了注汽方式,建立了蒸汽驱技术界限。预计实施蒸汽驱后提高采出程度19.1%,可为同类油藏实施大井距蒸汽驱开发提供借鉴经验。

Es44 of Block Cao 4 in Le'an Oilfield was a common heavy-oil reservoir with weak edge water,it was developed by using steam soaking with well space of 200m×283m.It entered into a stage of multiple soakings and it was faced with some problems,such as rapid cyclic production decline,rapid pressure reduction and low oil recovery.To greatly improve oil recovery ratio in the block and in consideration of economic profit,reservoir engineering analysis and numerical simulation methods were used to study the feasibility of steam soak at space of 200m×283m and validity time of steam soaking.The method of steam flooding are determined,the technical limits of steam soaking are established,It is predicted that 19.1% oil recovery ratio should be enhanced in steam flooding,it provides reference for steam flooding in large space of wells in the similar reservoirs.