摘要
低渗透稠油储层具有明显的启动压力梯度,该文首先基于分析低渗透油藏弹性能量开发中的不稳定渗流过程,得到拟稳态条件下直井开发渗流方程的基本解;再利用保角变换方法,建立考虑启动压力梯度影响下,水平井在三维空间上压力分布的计算模型。考虑技术和经济因素,提出了低渗透稠油油藏衰竭开发下水平井储量有效动用界限,包括满足渗流速度要求的最大动用范围以及满足经济极限累计产油量要求的最小动用范围,并建立了相应的计算方法。研究结果表明,对于低渗透稠油油藏,要综合考虑技术和经济条件的要求,在满足水平井储量有效动用界限的基础上确定开发井距,才能对此类油藏进行有效开发。通过X-DEH油田开发实例,研究了不同储层物性和开发条件下,水平井在水平平面动用半径和垂直平面动用厚度的变化规律,结果表明该方法具有很好的可操作性。
Porous flow mechanism in low-permeability heavy-oil reservoirs is not in line with Darcy flow because of the existence of threshold pressure gradient. Based on characteristics of porous flow in low-permeability heavy-oil reservoirs, the unsteady flow driven by natural elastic energy is studied to get the solution of flow equation which is in pseudo-steady state and takes into account the influence of threshold pressure gradient in vertical wells. Then according to the theory of conformal transformation, a model is built for calculating three-dimension distribution of pressure in horizontal wells which take into account the effect of threshold pressure gradient. Considering some factors of technology and economics, the effective drainage limit for low-permeability heavy-oil reservoirs driven by natural elastic energy is put forward and corresponding computingmethod is also given. It includes the maximum effective drainage radius for flow velocity and the minimum effective drainage volume for economic limit of cumulative oil production. The results indicate that, both technical and economic demands should be considered and the development well spacing on the basis of effective drainage volume of horizontal wells need to be determined reasonably. Then the low-permeability heavy-oil reservoirs could be exploited effectively. Combining with the practical examples in X-DEH oilfield, the variations of effective drainage radius of horizontal wells in horizontal and vertical plane are studied in different conditions of reservoirs and development. The results indicate that this method is quite practicable.
出处
《水动力学研究与进展（A辑）》
CSCD
北大核心
2014年第1期9-17,共9页
Chinese Journal of Hydrodynamics
基金
国家科技重大专项(2011ZX05031-002-007HZ
2001ZX05030-005-05)~~
关键词
低渗透稠油油藏
启动压力梯度
水平井
保角变换
储量动用界限
low-permeability heavy-oil reservoirs
threshold pressure gradient
horizontal wells
conformal transformation
limits of effective drive in reservoir
