Spatial distribution prediction of pre-Sinian volcanic and metamorphic rocks in Xinhenan-Sandaoqiao area, Northern Tarim Basin

Abstract

The main type of oil and gas reservoir in the Xinhenan-Sandaoqiao area is buried hills. The distribution pattern and scale of reservoirs in this area are obviously controlled by pre-Sinian basement strata. However, the lithologic combination and spatial distribution pattern of the pre-Sinian basement in this area are still unclear. We have used the method of multifactor comprehensive analysis to study the spatial distribution of pre-Sinian basement volcanic and metamorphic rocks. First, we determine the lithology and lithologic association of volcanic and metamorphic rocks according to cores and thin sections. Guided by the seismic reflection characteristics of different lithologic combinations, different lithologic combinations are identified on the profile by combining the seismic reflection characteristics of single well and multiwell. Second, using cluster analysis technology, we select three seismic attributes that are sensitive to lithology from 10 attributes, make crossplots of the three seismic attribute values, and ensure the distribution range of attribute values corresponding to different lithologic combinations for plane lithologic identification. Finally, we combine the recognition results of the plane and the profile to summarize the plane lithology distribution of the pre-Sinian basement surface. Six distribution types were identified deep metamorphic bedrock area in Kuqu depression, dynamic mixed metamorphic rock and intermediate-acidic intrusive rock area, metamorphic bedrock in thrust napple slopes area, thermal contact metamorphic rock area, intermediate-acidic intrusive rock area, and dynamic metamorphic rock area and gneiss area in faulted uplift core.