摘要
为了实现对致密储层的高效开采，文中提出了致密储层聚簇孔定向开采方法。该方法在深部储层范围内用机械钻孔破岩方式，沿井眼的轴向长度方向钻出一系列孔簇，并且1个截面内可同时钻出3个深度和方向可调控的孔簇。基于致密储层渗流机理和油水两相渗流理论，建立数值计算模型，对致密储层聚簇孔进行渗流模拟。研究对比发现：1）致密储层聚簇孔定向开采方法周围泄油面积呈T形，致密储层泄油面积达到最大，产油量均高于4种不同展布（对称分支60°、非对称分支60°、对称分支90°、非对称分支90°）的鱼骨形分支水平井；2）渗透率、孔隙度与致密储层聚簇孔产能都呈正相关，而启动压力梯度与致密储层聚簇孔产能呈负相关；3）在相同条件下，渗透率对储层产能的影响比孔隙度的影响大；4）启动压力梯度对致密储层聚簇孔产能有着不可忽视的影响，启动压力梯度越大，流体渗流所要克服的阻力就越大，致密储层产油量越低。研究结果可为致密储层聚簇孔的结构优化与改进提供技术指导。
Abstract
In order to realize efficient exploitation of tight reservoirs, this paper proposes a directional mining method for clustered pores in tight reservoirs. In this method, mechanical drilling is used to break rock in the deep reservoir, and a series of pore clusters are drilled along the axial length of the wellbore, and three pore clusters with adjustable depth and direction can be simultaneously drilled in one section. Based on the seepage mechanism of tight reservoirs and the oil-water two-phase seepage theory, a numerical calculation model was established to simulate the seepage of clustered pores in tight reservoirs. The research by comparison show that: (1) the oil drainage area around the clustered pores in tight reservoirs is in a T-shaped form, which maximizes the oil drainage area in tight reservoirs, and the oil production is higher than that of the four different distributions(symmetric branch 60°, asymmetric branch 60°, symmetrical branch 90°, asymmetric branch 90°) of fishbone-type branched horizontal well; (2) permeability and porosity are positively correlated with productivity of the clustered pores in tight reservoirs, while the threshold pressure gradient is negatively correlated with productivity of the clustered pores in tight reservoirs; (3) under the same conditions, permeability has a significant effect on reservoir productivity rather than that of porosity; (4) the starting pressure gradient has a non-negligible effect on the productivity of clustered pores in tight reservoirs. The greater the starting pressure gradient, the greater the resistance to be overcome by fluid seepage, and the lower the oil production in tight reservoirs. The research results can provide technical guidance for structural optimization and improvement of clustered pores in tight reservoirs.
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