Inversion-Based Method Integrating Sonic and Resistivity Logging Data for Estimation of Radial Water Saturation Profile and Porosity Near the Wellbore

2014 ◽  
Author(s):  
Sushil Shetty ◽  
Lin Liang ◽  
Terek M. Habashy ◽  
Vanessa Simoes ◽  
Austin J Boyd ◽  
...  
Keyword(s):  
Water Saturation ◽  
Resistivity Logging ◽  
Saturation Profile

Modification of Welge's Method of Shock Front Location in the Buckley-Leverett Problem for Nonzero Initial Condition (includes associated papers 15193 and 15282 and 15797 and 15915 and 16458 )

1985 ◽  
Vol 25 (04) ◽  
pp. 521-523 ◽  
Author(s):  
M.F.N. Mohsen
Keyword(s):  
Analytical Solution ◽  
Water Saturation ◽  
Mass Conservation ◽  
Residual Water ◽  
Initial Condition ◽  
Fractional Flow ◽  
Space Domain ◽  
Zero Initial Condition ◽  
Nonzero Initial Condition ◽  
Saturation Profile

Abstract In the analytical solution of the Buckley-Leverett problem, Welge1 recommends that to locate a front, one should draw a tangent to the fractional saturation curve from the origin. In this paper I establish that this procedure will be correct only for the case of a zero initial condition. For a nonzero initial condition, a mass-conserving front will be located farther down the flow direction. The implications of this finding for error analysis in comparing numerical solutions to the analytical one are discussed. Introduction To establish the accuracy of a numerical solution to the Buckley-Leverett equation, one normally seeks a comparison with the analytical solution. Difficulties arise, however, when a zero initial saturation over the space domain, normally imposed on the analytical solution, is to be expressed numerically while incorporating a nonzero boundary condition. For example, the finite-element method using a "Chapeau" basis function by necessity generates a ramp initial condition. The objective of this paper is to provide a modification to Welge's1 method for an appropriate location of the front on the basis of mass conservation for a condition where some water greater than the residual water saturation is initially present. The analytical solution to the Buckley-Leverett equation is known to yield a multiple-value saturation profile that is resolved by locating a front on the basis of mass conservation. This was suggested by Buckley and Leverett.2 A quick way of locating the front was provided by Welge,1 and is also discussed in Ref. 3. Welge's method locates the front accurately for the particular case when the initial saturation is zero (or a constant residual water saturation) over the entire space domain. In the more general case of a nonzero initial condition (i.e., initial saturation greater than residual saturation), his method needs modification. One such method is presented in this paper. Development of the Modified Technique The Buckley-Leverett equation is given byEquation 1 whereqt=total volumetric flow rate (L3/T),fw=fractional flow of wetting phase,Sw=saturation of wetting phase,t=time (T),x=space coordinate (L),A=cross-sectional area normal to flow (L2), andf=porosity. Introducing ut=qt/Af, the total interstitial flow velocity, Eq. 1 may be written asEquation 2 It was shown by Buckley and Leverett2 that the solution to Eq. 2 may be generated by computing the displacement, ?x, experienced by any saturation, Sw.Equation 3 Owing to the bell-shaped property of dfw/dSw as a function of saturation Sw, the solution of Eq. 3 generates a triple-value function, ?x(Sw,t). The physical incompatibility of the multiplicity of Sw at a given x on the advanced saturation profile of the wetting phase was resolved by Buckley and Leverett2 by locating a front while maintaining conservation of mass. Welge1 rightfully pointed out the computational effort in computing the area every time a solution is required. He established that the mass-conserving front location may be arrived at by drawing (in the fw vs. Sw plane) a tangent from the origin (Sw=Swr, fw=0) to the fw(Sw) curve. The saturation at the point of tangency is the saturation at which the front is to be located. I now show that Welge's method will yield the correct front location only in the special case of zero initial condition - i.e., when Sw(x,0)=Sw for all x. For the more general case of a nonzero (over and above Sw) initial condition, Welge's method will be modified. A nonzero initial condition affects the solution in two respects.

Propogation LWD Tool Analysing for Better Saturation Estimation in High Angle Horizontal Well Conditions

2021 ◽  
Author(s):  
Airat Mingazov ◽  
Andrey Zhidkov ◽  
Marat Nukhaev
Keyword(s):  
Horizontal Well ◽  
Water Saturation ◽  
Reservoir Properties ◽  
Resistivity Measurements ◽  
Well Completion ◽  
Geological Conditions ◽  
Formation Resistivity ◽  
Time Propagation ◽  
Resistivity Logging ◽  
Logging Tool

Abstract Multidepth electromagnetic logging tool is considered as traditional measurements of formation resistivity estimation while drilling. When considering data in wells with high angles trajectory, more than 70 degrees, the resistivity measurements could be affected by several factors associated with geological conditions and logging tool specifications. As the result, during water saturation estimation formation properties could be distorted, which will lead to significant effect of reservoir properties assessment and the design of the horizontal well completion. Within the framework of this paper, various methods of influence on the resistivity readings will be considered, especially with cross boundary effects and reservoir formations with anisotropy. At the same time, propagation resistivity logging technologies while drilling with interpretation and boundary propagation technologies will be observed, which has tilted azimuthal oriented receivers for geosteering service of horizontal wells and additionally helps with take into account of boundary enflurane on standard resistivity logging.

Imaging Radial Distribution of Water Saturation and Porosity Near the Wellbore by Joint Inversion of Sonic and Resistivity Logging Data

2016 ◽  
Vol 19 (04) ◽  
pp. 713-730
Author(s):  
Sushil Shetty ◽  
Lin Liang ◽  
Tarek M Habashy ◽  
Vanessa Simoes ◽  
Austin J Boyd ◽  
...  
Keyword(s):  
Radial Distribution ◽  
Water Saturation ◽  
Joint Inversion ◽  
Resistivity Logging

All-Time Modeling of Co-Current Spontaneous Water Imbibition Into Gas-Saturated Rocks Using a Novel Transition Time

2020 ◽  
Vol 143 (6) ◽  
Author(s):  
Lin Jia ◽  
Kewen Li ◽  
Lipeng Zhao ◽  
Bhekumuzi Mgijimi Mahlalela
Keyword(s):  
Water Saturation ◽  
Spontaneous Imbibition ◽  
Production Performance ◽  
Petroleum Reservoir ◽  
Gas Reservoirs ◽  
Time Model ◽  
Water Imbibition ◽  
Time Modeling ◽  
Capillary Pressures ◽  
Saturation Profile

Abstract Spontaneous imbibition (SI) into a porous medium is an important transport phenomenon in petroleum reservoir engineering. The study of spontaneous water imbibition is critical to predict the production performance in these reservoirs developed by waterflooding, especially in the fractured gas reservoirs with active aquifers. While some studies have been reported to characterize spontaneous water imbibition into gas-saturated rocks, they are either limited or inaccurate due to the fact that the existing models have specific assumptions that cannot be applied in other time intervals. To this end, we proposed a novel transition imbibition time t* and developed an all-time (including both early- and later-time SI) model to match the experimental SI data. Furthermore, we proposed a novel model to estimate capillary pressures at different water saturations and to characterize the water saturation profile in capillary-dominated stage. Comparison with the existing capillary pressure estimation models was performed to test the differences. The results demonstrated that the all-time model could fit the experimental imbibition data of the entire SI process satisfactorily. The new saturation model established in this paper can be well fitted with the water saturation profile measured by the X-ray computer tomography (CT) scanners. The results and findings from this work may be of great significance in many areas related to SI, particularly in the development of naturally fractured gas reservoirs with active aquifers.

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