Study On The Acquisition Plan Of Secondary Seismic Exploration In The Pearl River Mouth Basin

With the deepening of the oil and gas field exploration and development,secondary exploration(rolling exploration and development)for oil and gas field becomes an important mode for solving the problem of complex geological and increasing reserve.In Pearl River Mouth basin,some fields' production decline year by year,the development cost of oil field increase gradually,the economic benefit gradually becomes poor,oil field has gradually entered the stage of rolling exploration and development.Therefore,rolling exploration and development work urgently need in the old oil field area.From the successful experience of land oilfield exploration,secondary exploration need to combine the reservoir exploration and development.On the basis of reservoir exploration,looking for new,deep oil and gas formation and implementation of the remaining oil distribution,combining with the existing production facilities,adjust the oil field development plan,realize the new growth of oil and gas,improve the overall economic benefits of oilfield development.This paper is faced with the problem in shallow water reservoir exploration of Pearl River Mouth basin,starting from the seismic data acquisition scheme,comprehensively analysis the factory area of wave field propagation characteristics,influence factors and so on,carries on the collection evaluation scheme according to the different schemes,The main results are listed as follows:(1)Formed basing on geological constraints well and seismic modeling methodBased on geological constraints well and seismic modeling method can well use the area logs and horizons interpretation information,characterized the area of seismic reflection characteristics.Kriging interpolation method is the main method of interpolation,it introduces the distance as the independent variable of variation function calculating weights.Variation function can reflect the structural composition,spatial data and can reflect the space variable random distribution,at the same time can describe the error information.Through designing the variation function,Kriging method is easy to implement local weighted interpolation,thus overcome the general inverse distance weighted interpolation method of interpolation results instability.Estimates value is equal to the theoretical results of expectations.(2)Analyze and evaluate the influence factors of the seismic wave field spreading and receivingThere are many influencing factors of seismic wave field spreading,illumination and imaging,they both exist independently and connect with each other.Stratigraphic tectonic characteristics and heterogeneity directly affect the spread of seismic wave field and illumination;Different bin size has a great influence on improving space sampling and reducing space aliasing;The characteristics of wavelet frequency band also have great influence to the seismic imaging;Source of energy,cable length and direction will affect the illumination,when the cable reaches a certain length,the information of illumination have little difference with different acquisition direction.(3)Based on analysis of forward modeling with different observation methodDifferent streamer spacing of the forward modeling results can be characterized its structure form,decreasing of the streamer spacing has large effect for the weak reflected signals,especially for the buried depth is less than 2500 m;The influence of deep reflection is limited;decreasing the streamer spacing makes characterization of lateral variation of lithology and stratigraphic contact relationship more accurate,makes imaging result has higher signal-to-noise ratio.Finally,guided the target area seismic data acquisition,through subsequent targeted process,got the high fidelity of seismic data.Through the data inversion,selected the advantageous targets,confirmed the reliability of the results by drilling.Targeted secondary exploration method has an important guiding significance to the exploration and development in pearl river mouth area.