Research On Building Of Pore Structure Parameters And Porosity Prediction Of The Reef Reservoir

Reef reservoir is an important oil and gas reservoir space. It has thecharacteristics of large reserve and high yield. But it is very difficult to predict thereef reservoir by using seismic data because of the strong heterogeneity of the reefreservoir. Seismic inversion can reflect the lithologic properties of reservoirs andgeological structures underground correctly, so it plays a more and more importantrole in oil and gas exploration. Since the porosity is an important parameter tocharacterize the properties of hydrocarbon reservoirs, this parameter obtained fromseismic inversion data is of great significance for oil and gas exploration researchwork. Previous studies have confirmed that the pore structure of the carbonatereservoir has a big influence on the seismic wave velocity. Against the difficulty of thereef reservoir prediction, the article analyzed the seismic response characteristics andlogging response characteristics in detail in the case of the Pearl River Mouth Basin(eastern). And on the basic various algorithms of the reef reservoir porosity predictionand their application were discussed. The results and understandings are as follows:(1)The author analyzed the seismic response characteristics and log responsecharacteristics of the biological reef.(2)This article adopted non-local mean algorithm to suppress the random noise inseismic data. We found that compared with the traditional denoising algorithm, thenon-local mean algorithm could preserve the edge information (such as geologicalfeatures of cracks and faults) in the image and improved the signal-to-noise ratio. Atthe same time it did not affect the resolution of the image.(3)The pore structure factor greatly affects prediction results in the porosityprediction of the reef reservoir. The study found that common petrophysical modelscannot be able to describe the change regulations of the rock structure in reefreservoirs well and the forecast effect won’t be ideal. If the pore structure factor wasconsidered, the prediction effect of the porosity prediction of the reef reservoir wouldbe improved. In the case of the Pearl River Mouth Basin, the article adopted theporosity inversion equations deduced from Eshelby–Walsh framework and Gassmannequation to predict the porosity of the reef reservoir. The results indicated that becausethe pore structure factor was considered, the porosity predicted and the actual porosityhad very high similarity.(4)The uniform rock framework is applicable to the reef reservoir prediction, andit has high accuracy for porosity inversion. The strong heterogeneity of the reefreservoir and the variety of the pore structure make the framework diversify, such asEsheby-Walsh, Pride, Lee and so on. In the case of the reef reservoir in the Pearl River Mouth Basin, the article adopted the uniform framework suggested by He Xileiin2012and Gassmann equation to do the porosity prediction research. It is pro vedthat this method is not only computed conveniently and has universal adaptability butalso improves the accuracy of porosity inversion.