Evaluation of reservoir deformation induced by water injection in SAGD wells considering formation anisotropy, heterogeneity and thermal effect
Evaluation of reservoir deformation induced by water injection in SAGD wells considering formation anisotropy, heterogeneity and thermal effect
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考虑地层各向异性、非均质性和热效应的 SAGD 井注水引起储层变形评价
DOI：
10.1016/j.petrol.2017.07.067
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发表时间：
2017-08-01
影响因子：
--
通讯作者：
Jin, Yan
中科院分区：
文献类型：
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作者：
Lin, Botao;Chen, Shengli;Jin, Yan
蒸汽辅助重力泄油（SAGD）开采稠油，通常采用水平井对注水的增产工艺，以扩大双威尔斯井周围区域的孔隙空间，建立井间水力连通，为后续开发提供巨大的效益。为了对增产措施的效率进行实际预测和评估，需要对注水过程进行模拟，并适当考虑岩石特性和现场条件。该研究提出了一种综合的模拟方法，该方法能够正确地捕获油砂的力学响应和注入过程中应变相关的渗透率演化，以及解决岩石物理变化沿着水平井筒和注入水的温度效应。以克拉玛依某油田真实的SAGD注水工程为例，采用室内标定的力学和水力参数，结合现场应力和边界条件，进行了模拟计算。模拟预测了储层不同部分的孔隙压力分布和膨胀剖面。一般情况下，预测结果的井底压力（BHP）与观察到的一致。相应的储层响应表明：（1）在现场注水条件和所考虑的岩层参数下，产层基本上经历孔隙弹性变形，（2）膨胀带的产生和发育取决于注入水的温度和在储层中的位置;（3）井间域中的增产程度明确地反映在双威尔斯井之间的温度响应中。这些研究结果不仅为油田生产工程师评价和改进增产措施提供了有价值的信息/指导，而且所提出的方法也可用于分析涉及其他类型疏松砂岩油藏的注水问题。
Heavy oil recovery using steam assisted gravity drainage (SAGD) usually adopts a stimulation process through water injection to the horizontal wellpair in order to expand the pore space in the domain surrounding the dual wells to establish the interwell hydraulic communication, which will offer great benefits for the subsequent development stages. For realistic predictions and evaluations to be made of the efficiency of the stimulation, simulations of the water injection process taking into appropriate account of the rock properties and field conditions are required. This study proposed a comprehensive simulation methodology, which is capable of capturing properly the mechanical responses of the oil sand and the strain-dependent permeability evolution during the injection, as well as of addressing the petrophysical variations along the horizontal wellbores and the temperature effect of the injected water. The simulations were conducted for a real SAGD injection project in an oil field located in Karamay, northwest China, using the mechanical and hydraulic properties calibrated with the laboratory data and the field stress and boundary conditions. The simulations predict the pore pressure distribution and the dilation profile across different sections of the reservoir. In general, the predicted results in terms of bottom hole pressure (BHP) agreed well with the observed. The corresponding reservoir responses disclose that (1) the pay zone basically experiences poroelastic deformations under the field injection conditions and the rock formation parameters considered; (2) the generated pore pressure and development of the dilative zone are dependent on the temperature of the injected water and the position in the reservoir; (3) the degree of stimulation in the interwell domain is explicitly reflected in the temperature responses between the dual wells. These findings not only provide valuable information/guidance for the field production engineers to evaluate and improve the stimulation work, but also the approach proposed may be used to analyze the water injection problems involving other types of unconsolidated sandstone reservoirs.