Development of a mapping method for complex fault-block variable-velocity structures in the later stage

Abstract

The invention provides a complex fault block velocity-varied structure mapping method in late development. The method comprises steps: 1, the interval velocity of a single well is acquired through a seismic interpretation horizon and a geological stratification; 2, horizon-oriented seismic attributes which can reflect lithological changes are extracted, and an attribute image and an equal T0 imageare superposed; 3, based on the principle of a consistent formation velocity at the same lithology and at the same time, velocity points of areas with no wells or with nonuniformly-distributed wellsare encrypted; 4, with the seismic interpretation horizon as a trend surface and with a fault boundary as an interpolation boundary, interpolation is carried out on the interval velocity of the singlewell, and a two-dimensional interval velocity field is built; and 5, the generated two-dimensional interval velocity grid and the equal T0 grid are multiplied for time-depth conversion, and a final structure map is obtained. The method provides accurate basic guidance for the study of a remaining oil distribution law and the development of well pattern reorganization in complex fault block fine reservoir description, a guidance role is played in late development of the reservoir of the kind, the prospect of popularization and application is broad, and economic and social benefits are remarkable.

Description

technical field [0001] The invention relates to the field of fine reservoir description of complex fault blocks, in particular to a method for mapping variable velocity structures of complex fault blocks in the later stage of development. Background technique [0002] Due to the influence of lithology, topographical structure and fault system in complex fault blocks, the vertical and lateral velocity of the formation velocity in many areas changes greatly, and the structure mapping accuracy is high in the later stage of development. The error between the time-depth conversion of the structural map and the wellbore is relatively large, which cannot meet the accuracy requirements, and it is necessary to use the variable speed structure to form the map. At present, there are many researches on variable-velocity mapping methods, mainly interpolating the velocity field from the well point velocity and calculating the three-dimensional average velocity field from the stacked veloc...

AI Technical Summary

Problems solved by technology

However, this method of calculating the three-dimensional velocity field from the stacking velocity is cumbersome, and generally structural interpreters do not have stacking velocity data, and all they can do is to calculate the velocity field from the well point velocity

Although there are many wells in fault-block reservoirs in the late stage of development, the interpolation method of well point velocity field is not accurate enough in places with few wells, uneven distribution of wells, and faults; therefore, in places where small faults and formations change, The velocity calculated by this method cannot truly show the characteristics of underground velocity changes, and the time-depth conversion will cause structural distortion

Images