Rock Mechanical Parameter Modeling of Tight Oil Reservoir: A Case Study of Certain Block

The lithology of the oil layer in the study area is dense and difficult to be developed. In order to clarify the distribution of in-situ stress field and rock mechanics parameters of this block, a shear wave slowness prediction model suitable for this area is established on the basis of the rock tested data, combining cross dipole acoustic (XMACII) data with conventional logging data. Through this prediction model, rock mechanics parameters such as Poisson's ratio and Young's modulus and in-situ stress of each well are calculated. Based on the 3D geological model, the high-resolution 3D rock mechanics parameter models of Poisson's ratio model, Young’s modulus model and in-situ stress field model are established by using the finite element simulation technology to simulate the in-situ stress and analyze its spatial distribution. The results show that the maximum horizontal principal stress generally directs EW-trending and is mainly distributed in 33.2~51.6 MPa, the minimum principal stress is mainly distributed in 28.8~46.5 MPa. When the horizontal stress difference is small in 2~4 MPa,it is easy to form a more complex mesh; While it is greater than 4MPa,a single horizontal joint is easily formed and the crack surface is relatively flat. Under the condition of less cross dipole acoustic construction, the study completed the characterization of the in-situ stress field by using shear wave slowness prediction. This study is helpful to designing reservoir fracture network fracturing simulation for tight oil reservoir, the average daily oil production of new well after fracturing construction reached 17.6t, realizing the efficient regional development of tight oil reservoirs.