Investigation of the impact of diagenesis on the petrophysical properties in the complex porosity systems in carbonates

摘要

The determination of petrophysical properties incarbonate rocks is strongly affected byheterogeneity at different scales. Complexdepositional and diagenetic processes have led tosystems with a very wide range of pore sizesinvolving many decades of length-scales (e.g.,from sub-micron to cm), which cannot be capturedby a single-resolution x-ray CT image.Calculations of flow parameters such aspermeability, relative permeability and capillarypressure do require the representative multiscalepore system to get accurate prediction. Thereforemodels of the pore space that include the full rangeof pore sizes and their connectivity are vital for thisrequirement in petrophysics and reservoirsimulation. Recently a multiscale pore-networksgenerated from statistical models extracted fromimages at different resolutions have shown as animportant tool for multiscale pore description (Wuet al, 2011). In this work we explore the extensionof this multiscale pore-reconstruction and imagestatistical description to include diageneticprocesses. We present a study of the impact ofdiagenetic processes on the evolution of carbonaterock by quantification of pore size andconnectivity, modelling the process of cementationand dissolution using derived information fromcatholuminescent thin section images indicatingvarious stages of diagenesis. The diageneticprocesses includes cementation and dissolution inboth the meteoric and burial diageneticenvironments and are modelled using PoreArchitecture model to dissolve grains in the regionsof the best connectivity estimated fromreconstructed 3D images of carbonate samples. Anintegrated multi-scale pore-network is thengenerated and the petrophysical predictions wouldbe performed on a pore-network flow simulator. Atlast a further study of comprehensive rock typingcombining diagenetic processes on poreconnectivity and petrophysical properties isinvestigated to better understand the diageneticcontrols of the pore system and transportproperties.