tailieunhanh - Báo cáo nghiên cứu khoa học: " STRESS VARIABILITY AROUND LARGE STRUCTURAL FEATURES AND ITS IMPACT ON PERMEABILITY FOR COUPLED MODELLING SIMULATIONS"

Một sự hiểu biết rõ ràng của sự căng thẳng đá và ảnh hưởng của tính thấm rất quan trọng trong mô phỏng cùng nơi sản xuất chất lỏng gây ra một sự gia tăng đáng kể trong sự căng thẳng hiệu quả trong một hồ chứa | Science Technology Development Vol 11 - 2008 STRESS VARIABILITY AROUND LARGE STRUCTURAL FEATURES AND ITS IMPACT ON PERMEABILITY FOR COUPLED MODELLING SIMULATIONS Ta Quoc Dung 1 Suzanne Hunt 2 1 University of Technology VNU-HCM 2 Australian School of Petroleum Manuscript Received on May 29th 2008 Manuscript Revised November 10th 2008 ABSTRACT A clear understanding of rock stress and its effect on permeability is important in a coupled simulation where fluid production causes a significant increase in the effective stress within a reservoir. Changing the in-situ rock stress state can alter the reservoir properties. As a result porosity and permeability could be affected due to the rearrangement of rock particles and the redistribution of sensitive pore structures. It is known that permeability is more sensitive to stress changes than porosity. Permeability reduction can range between 10 and 30 as reported in previous publications this is within the elastic range of the material under investigation. Once the material reaches its yield strength a dramatic increase in permeability can then occur or further reduction depending on the mode of failure of the rock type in question. This study reports on permeability reduction under increasing stress within the elastic range for a number of rock types the samples tested are from the Cooper Basin of South Australia the standard Berea Sandstone is included for validation purposes. The results are used within a newly developed finite element coupled code in order to estimate permeability sensitivity to stress changes for predicting compaction and subsidence effects for a cylindrical wellbore model. Furthermore understanding rock mass stress away from the borehole is a major obstacle in the exploration and development of hydrocarbons. It is standard practice in the petroleum industry to use drilling data to determine the orientation and estimate the magnitudes of principal stresses at depth. However field observations .