ANALYTICAL MODELING AND VERIFICATION WITH NUMERICAL METHODS AND EXPERIMENTS OF THREE PHASE REACTIVE MATERIALS, DRILLING, CEMENTING AND PERFORMANCE OF SMART CEMENTED MODEL OIL WELLS

Date
2016-12-15
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Abstract

In this study new analytical models were developed based on using a nonlinear rheological model to predict the drilling and cementing of the oil well. Also, the long term performance of a model field well that was cemented using the smart cement was predicted using a nonlinear piezoresistive model and numerical model. The new reactive three phase material model was developed to characterize the three phase material with reactive constituents and to introduce the six independent reactive material parameters that depend on the curing time, temperature and pressure which contribute to the phase transition. This model can be used for any material with three phases such as cement, drilling mud, filter cake, oil rich rocks and medicines. In order to verify the model, cement slurry with water-cement ratio of 0.4 was tested for over 800 days. The changes in the weight, volume and the moisture content with the curing time was monitored to quantify the change in the three phases. Influence of the six material parameters on the shrinkage, porosity and electrical resistivity of the solidified cement were verified. The resistivity of the cement was influenced by the one reactive model parameter that represented the direct reaction of the liquid phase with the solid phase. The fracture behavior of smart cement was also evaluated using the electrical property monitoring tools in addition to the crack mouth opening displacement (CMOD) gauge. Also, Vipulanandan failure model for material was compared with Drucker–Prager criterion and verified with experimental results. In this study, well drilling and casing installation was investigated analytically using the new shear thinning rheological model. The analytical model predictions were compared to the Newtonian model. The Newtonian model over predicted the flow velocities and shear stress by 300%. Also, the analytical solutions were verified using numerical method. The effects of eccentricity for axial flow is investigated numerically while the eccentricity effect is analyzed analytically for the vortex flow. Later on, a new kinetic model has been developed assuming that the permeability and solid content during the filter cake is changing with time, temperature and pressure using Hyperbolic Model. The new kinetic model was verified with results from of fluid loss and compared with the API model. Also pumping of cement slurry during the well installation was investigated in terms of shear stress developed at the casing and geological formation interfaces. Three physical models simulating the cemented wells (including small model, large model and field model) were tested. During the test, the pressure applied inside the casing in small and large model test and the change of resistivity in smart cement were measured and p, q model was used to correlate the casing pressure to the cement resistivity changes. The numerical model analyzed to define the stresses and displacement along and around the wellbore and verified with the stress predicted from piezoresistivity effects. The smart cement will also predict the pressure inside the well.

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Keywords
Drilling, Vortex, Installation, Cemented Casing, Three Phase Reactive Material
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