سال انتشار: ۱۳۸۵

محل انتشار: اولین کنگره مهندسی نفت ایران

تعداد صفحات: ۱۳

نویسنده(ها):

Mohammad Ali Aghighi – School of Petroleum Engineering, The University of New South Wales

چکیده:

Pore pressure depletion during production from a hydrocarbon reservoir, can result in reorientation of horizontal principal stresses. This yields an opportunity to improve recovery factor through creating a secondary fracture in a direction perpendicular to the initial fracture plane. A fully coupled 2D numerical poroelastic model is used to
analyze the role of the parameters affecting on size and timing of the stress reversal zone. The results show that higher magnitude of initial pressure gradient and/or formation porosity lead to a larger stress reversal region in a wider optimal time window, while lower initial differential horizontal stresses and/or less compressible rock matrix have the similar impact. It is also shown that the formation intrinsic permeability has significant impact on the dimensions and duration of the region whether in isotropic or anisotropic cases. While formations with lower permeability generally have more potential of stress reorientation, a permeability anisotropy case where the higher permeability is in the direction of the initial fracture is also favorable for a refracturing purpose. Furthermore, in a reservoir with a long initial fracture, a larger stress reversal zone in a significantly wider time window is expected.