Investigation of mud filtrate invasion using computational fluid dynamics

Abstract

Despite continued research and developments in logging technology, logs processed by the prevalent standard methods continue to be influenced by formation damage and mud filtrate invasions. The mud-filtrate invasion and related formation damage due to drilling fluids can result in the misinterpreted values of rock and fluid properties in the reservoir which can affect the well plan. Well planning with accurate information of target reservoir is a very important part of any drilling procedure, as it would not only optimize drilling operation and completion but also maximizes production of oil and gas. To produce hydrocarbons effectively, the wellbore must communicate with formations beyond the altered zone and this can be accomplished by using proper perforations, penetration or creating fractures. Thus, the prediction of invaded zone is critical and a numerical model can be employed for preplanning purposes. In this study, the dynamic filtration process and the related penetrations into the gas and oil bearing reservoirs were studied in a vertical open hole system using a Computational Fluid Dynamics (CFD) software package. The radius of filtrate invasion was determined by the unsteady-state three-dimensional multiphase fluid flow model. The communication between fluids and formations during drilling and the effects of formation porosity and permeability, time, and overbalanced pressure were Suyoun Won INVESTIGATION OF MUD FILTRATE INVASION USING COMPUTATIONAL FLUID DYNAMICS ABSTRACT investigated extensively. Non-Newtonians drilling fluids such as Bingham plastic, Power-law, and Herschel-Bulkley fluids were also considered for the study. The Mud filtrate invasion in a multi-layer reservoir model and effect of hydraulic fracturing operations were examined. The results provide an insight on the formation damage around wellbore and related reduction in the hydrocarbon flow due to altered fluid saturations. The importance of accurate prediction of damaged zone around the well bore for the purpose of drilling fluid design, log interpretation, hydraulic fracturing and well completion is explicit from the results. iv ACKNOWLEDGEMENT This Thesis, "Study on formation damages under the various formation and operation conditions using Computational Fluid Dynamics", was suggested by Dr. Ilkin Bilgesu. First and foremost, the light of God's countenance has helped me in completing this thesis. A special word of thanks to my wife Minjae Lee, my father Jongtae Won, mother Youngbun Rho, and sisters Jihye and Eunhye. Without their everlasting love and support, this thesis would not have been success. I am truly grateful to my advisor Dr. Ilkin Bilgesu for his continued guidance, encouragement, and support throughout the development of this research.

Analyzing the Origin of Low Resistivity in Gas-Bearing Tight Sandstone Reservoir

“…A limited-size 3D single well formation model was established to simulate the mud invasion process by using reservoir numerical simulation technology [31][32][33][34]. Figure 8 shows the diagram of the mud invasion occurrence model.…”