Prediction And Analysis Of Shale Gas Formation Pressure In M Block

Shale gas,as a kind of alternative clean energy,is widely distributed in China.Reasonable development and use of shale gas is of great significance to alleviate the energy shortage,improve the structure of energy use,promote the development of industrial level,improve people’s livelihood and protect the environment.As a kind of unconventional oil and gas reservoir,shale gas has been studied by a large number of scholars,which shows that there is a great relationship between its formation pressure and its production capacity.High pressure often means high production.Accurate pressure prediction can provide reference for subsequent shale formation well location deployment and resource evaluation In addition,predrilling pressure prediction can effectively prevent well blowout and other drilling accidents.People began to study the method of stress prediction in the 1960 s,and it has developed up to now.However,due to the complexity of the cause mechanism of overpressure,a complete theoretical system has not been established yet.Most of the existing pressure prediction models are empirical relations.There are applicability problems in different work areas,and the accuracy of the velocity field used to calculate the pressure is not enough,which makes the pressure prediction work more difficult.Aiming at these problems,this paper takes M block as the research area to carry out pressure prediction work.It mainly includes the following contents: 1)Based on the study of the basic theory of pressure prediction,the characteristics of the existing pressure prediction methods are compared and analyzed,and compared in the work area,it is found that only relying on the longitudinal wave velocity to calculate the pore pressure will cause a large error in the work area;3)According to the core parameters of pressure prediction and the establishment of velocity field,based on the combination velocity field put forward by the predecessors,the result is more in line with the geological law,and it is applied in the work area with better effect.4)In view of the problem that the contribution of structural stress to formation pressure cannot be ignored in the complex geological structure of the work area,a high-precision prediction technology of abnormal formation pressure based on comprehensive logging seismic geological data is proposed: the logarithmic filliptone formula only considers the vertical stress to the three-phase stress coupling form.This method is different from the conventional one-dimensional calculation model,and introduces the horizontal in-situ stress fitting related to the geological structure.Compared with the prediction results of single well in M work area,the accuracy of this method is higher than that of conventional pressure prediction method,which is suitable for this work area;Through practical application,the improved combined velocity field and the pressure prediction model of comprehensive logging seismic geological data are used for three-dimensional pressure prediction.The pressure prediction in M work area is successful,and the subsequent exploration area is pointed out,which has certain practical value.