自动优化设计在过渡带三维地震勘探中的应用

Application of Auto-optimization Design to Three-dimensional Seismic Exploration in Transitional Zone

在复杂过渡带三维地震勘探项目中,施工设计包括海陆观测系统设计、从属线束设计、偏点设计等,其优化对于提高地震数据采集效率,保证资料品质,减少空炮、废炮和重炮,实现资料无缝连接至关重要。这就要求技术人员针对工区特点提前合理设计特殊观测系统,优化炮点布设,从而最大限度地满足覆盖次数均匀的需要。通过自动优化设计施工方式,可以减少人工误差,使采集结果最大限度地实现设计要求,从而提高效率、节约成本。

The conventional transition zone in three-dimensional（3D）operational design is made by splitting the operational area into two parts（land and ocean）in accordance with the basic parameters of the contract after scouting the practical water depth,obstacles,and terrain.Then the acquisition can be made according to two kinds of geometry.of course,the kinds of sources are different due to water depth and land terrains;there are different guns,explosives,and vibroseis.During the period of design,the design of offset points is finished by using professional software,such as green mountain or KLseis.When acquisition is completed,the offset point＇s optimization is made.There are three problems in the actual operation.Firstly,the progress of the project is limited to permit progress,and permits are very difficult to get in some places,which affect the production schedule.Secondly,the design period is longer due to the conventional design methods.Thirdly,for the complex region,the late offset point optimization makes it very difficult to meet the requirements of the original design,which results in void or invalid shots and affects the economic benefits.Because of these problems,it is urgent to find a method to make design flexible and fast.This design can reduce the design period,improve the design efficiency,and meet the requirement of uniform fold to the maximum extent in the process of optimization design.It is even more important in complex transition zone 3Dseismic exploration projects.Our operational designs include ocean geometry,land geometry,sub-swath,and offset point designs.It is vital for the optimization of the operation design method to improve the seismic data acquisition efficiency,ensure the data quality,reduce duplication of shooting,and realize a seamless connection of the data.This requires that the technician designs special micro-geometry and optimizes shot layout in view of project characteristics to meet the needs of maximum uniform fold.This paper presents an automatic optimization design method,that is to say,using aprogram to optimize reduces the manual errors,makes the acquisition results realize design requirements,and then improves the efficiency.This paper provides a detailed example and gives the detailed flows of design and offset point optimization.Application of automatic optimization design in complex 3Dtransition zone projects has the following advantages：（1）Flexible application of micro-design or sub-swath design can deal with the relationship between the production schedules and operational efficiency very well.（2）Application of offset point optimization design can effectively reduce void shots,invalid shots,and duplicated shots,which will effectively decrease production costs,shorten the design period,and improve production efficiency.（3）According to the principle of the offset point optimization design,combined with information about the water depth and other obstacles,land and ocean acquisition geometries can be divided,the excitation region can also be easily achieved,and the excitation sources include vibroseis,explosives,and different kinds of air guns.（4）The coordinates of obstacles which the survey department provides can be directly used to offset optimization design,which significantly simplifies the computation steps and saves design time.（5）Automatic optimization design and its flow that the paper gives provide a basis for complex transition zone operations.