鄂尔多斯盆地板桥-合水与姬塬地区长6储层主控因素分析

Reservoir Main Controlling Factors of Chang 6 Sandstones in Jiyuan and Banqiao-Heshui Areas of Ordos Basin

鄂尔多斯盆地西南部板桥-合水地区与西部姬塬地区延长组长6储层,虽然处于同一层位但物性存在较大差异。通过铸体薄片、SEM、X射线衍射等实验手段并结合测井资料,主要围绕沉积作用、成岩作用应用类比法分析了2个地区储层物性产生差异的原因,明确了储层主控因素。研究表明:沉积作用对储层的控制是先天性的,是控制储层物性好坏的决定性因素,在沉积作用控制储层物性3个因素——岩石碎屑组分的含量、结构成熟度、沉积微相中沉积微相对储层物性的影响最大;成岩作用是控制储层层内孔喉结构差异的主要因素,其中压实作用对储层的物性破坏最大,使2个地区的孔隙度分别丧失了27.58%和22.31%。总而言之,储层的物性受成岩作用、沉积作用及构造作用的共同影响,其中导致2个地区储层物性产生较大差异的主控因素是沉积作用中的碎屑组分含量、沉积微相以及成岩作用中的压实作用。

There are obvious differences of reservoir physical properties of Chang6 sandstones between the Jiyuan area in the west and the Banqiao-Heshui areas in southwest area of the Ordos Basin though they are in the same level. In order to analyze the reservoir main controlling factors and the mechanism of differ- ences, this study used the casting thin sections, SEM, X-ray diffraction experiment method combined with the logging data mainly around the diagenesis,sedimentation to determine the main reasons for the differ- ence of the reservoir physical properties in the two areas. The results show that sedimentation is the con- genital and decisive factor to control the quality of the reservoir, which controld the reservoir property by controlling the elastic rock components, maturity structure and the sedimentary micro-phase. In these three factors sedimentary micro-phase is the greatest influence of the reservoir. Diagenesis is the major factor for the pore structure difference, while compaction is the largest destructive factors for the reservoir physical property which makes the porosity of the two regions lost 27. 580% and 22.31% respectively. Clastic com- position, sedimentary micro-phase of sedimentation and compaction of diagenesis should be the main con- trolling factors for the difference of reservoir physical property.