The Application Of Walkaway VSP Technology In The Oilfield Development

Conventional VSP is a well-ground exploration method that the receiving system is fixed in well while the shot point is on the ground. Conventional VSP can decrease at least half of the attenuation's effection due to the surficial low velocity layer, so as to make the resolution of the seismic signal received in well higher than that on the ground. In addition, we can hold the exact position of the receive points in well and the receivers are also very close to the goal layer. Therefore, this method have much more obvious advantages than surface seismic method on the ascepts of analysing seismic velocity, imaging the stratal structure accurately and analyzing the seismic attribution. It plays an important role in demarcating and adjusting the seismic data on the ground, offsetting its disadvantages within its detection range. On processing and interpretating the seismic data on the ground, it offers the corresponding parameter information and scales including polysomatic information.Walkaway VSP is a special way of the conventional VSP. The main difference between them is that the shotpoints on the ground is not one but a set of linear shotpoints which pass through the observation well and distribute regularly. Under multifold situation, it can proceed accurate imagery for the stratal structure and the distribution feature of the goal layer within some range beside the well, hence it plays an important role on establishing the well-seismic relationship and evaluating and exploiting oil/gas reservoir.On the basis of analyzing and expounding the basic theory and technique, the paper analyses and discusses stressly the acquisition, process and interpretation of the data involved under the Walkaway VSP method and its application problem on exploratory development of the oil region, discussing detailly its distinguishing feature and difficulty.Using the zero offset and walkaway VSP data of the oilfiled development area, combining the well drilling geology data, the well logging data, the testing data after casting, the production performance data and the 3D seismic data on the ground, the paper analyses and researches synthetically the application problem of the VSP method, especially the scale function of the VSP data. In addition, it also analyses many problems, such as the tense of the data used in the development area, the adjustment of multi-reserviors parameters inversion method and the application of the seismic attribution parameters and the resilience attribution parameters. On such basis, it carries out the results which include the accurate structural analysis of the VSP exploration area, the pre-determination of the fracture development band, the seismic facies-sedimentary facies section pre-determination, the pre-determination of seismic reservoir and interbedded stratum distribution as well as the pre-determination of the character and distribution of the fluid in the reservoir. After being verified, the total result is more dependable and has a higher practical value.