RESEARCH ARTICLE 3D structural modeling integrated with seismic attribute and petrophysical evaluation for hydrocarbon prospecting at the Dhulian Oilfield, Pakistan Umair KHAN 1 , Baoyi ZHANG (✉) 1 , Jiangfeng DU 2 , Zhengwen JIANG 1 1 MOE Key Laboratory of Metallogenic Prediction of Nonferrous Metals & Geological Environment Monitoring/ School of Geosciences & Info-Physics, Central South University, Changsha 410083, China 2 CNOOC Research Institute Co. Ltd., Beijing 10028, China © Higher Education Press 2021 Abstract Surface and deep subsurface geological struc- tural trends, stratigraphic features, and reservoir charac- teristics play important roles in assessment of hydrocarbon potential. Here, an approach that integrates digital eleva- tion modelling, seismic interpretation, seismic attributes, three-dimensional (3D) geological structural modeling predicated on seismic data interpretation, and petrophysi- cal analysis is presented to visualize and analyze reservoir structural trends and determine residual hydrocarbon potential. The digital elevation model is utilized to provide verifiable predictions of the Dhulian surface structure. Seismic interpretation of synthetic seismograms use two- way time and depth contour models to perform a representative 3D reservoir geological structure evaluation. Based on Petrel structural modeling efficiency, reservoir development indexes, such as the true 3D structural trends, slope, geometry type, depth, and possibility of hydro- carbon prospects, were calculated for the Eocene limestone Chorgali, upper Paleocene limestone Lockhart, early Permian arkosic sandstone Warcha, and Precambrian Salt Range formations. Trace envelope, instantaneous fre- quency, and average energy attribute analyses were utilized to resolve the spatial predictions of the subsurface structure, formation extrusion, and reflector continuity. We evaluated the average porosity, permeability, net to gross ratio, water saturation, and hydrocarbon saturation of early Eocene limestone and upper Paleocene limestone based on the qualitative interpretation of well log data. In summary, this integrated study validates 3D stratigraphic structural trends and fault networks, facilitates the residual hydrocarbon potential estimates, and reveals that the Dhulian area has a NE to SW (fold axis) thrust-bounded salt cored anticline structure, which substantiates the presence of tectonic compression. The thrust faults have fold axes trending from ENE to WSW, and the petrophysical analysis shows that the mapped reservoir is of good quality and has essential hydrocarbon potential, which can be exploited economically. Keywords surface model, seismic interpretation, subsur- face structural model, attributes, hydrocarbon potential 1 Introduction Hydrocarbon exploration is increasingly performed under more complex geological conditions; therefore, systematic operations are needed to optimize oil production to meet global energy needs (Nanda, 2016). Three-dimensional geological modeling is needed to express geological characteristics (e.g., shapes of geological structures, relationships among geological bodies, spatial distribu- tions of geophysical and geochemical properties of geological bodies) in an appropriate computer data structure (Houlding, 1994; Lajaunie et al., 1997; Mallet, 2002; Wu et al., 2005; Zhang et al., 2018). Therefore, the use of integrated methods, e.g., digital elevation models (DEMs), surface slope analysis, 2D seismic interpretation, and 3D structural modeling based on seismic interpreta- tion, seismic attributes, and petrophysical analysis of reservoirs, can identify geometric features, reveal internal and external reservoir structures, and quantitatively evaluate reservoir properties (e.g., lithology, porosity, permeability, net pay zone thickness, water saturation, and hydrocarbon saturation). The results obtained from such work can be applied to increase productivity, revitalize oil fields, predict future reservoir productivity, and indicate accurate financial consequences for oil and Received October 26, 2020; accepted February 7, 2021 E-mail: zhangbaoyi@csu.edu.cn Front. Earth Sci. https://doi.org/10.1007/s11707-021-0881-1