A Semi-Analytical Model Based on the Volumetric Source Method to Predict Acid Injection Profiles of Horizontal Wells in Carbonate Reservoirs

2020 ◽  
Vol 143 (5) ◽  
Author(s):  
Yongsheng Tan ◽  
Qi Li ◽  
Haitao Li ◽  
Xiang Zhou ◽  
Beibei Jiang

Abstract Acid treatment is an important measure to improve production for horizontal wells of carbonate reservoirs. Acid injection profile of horizontal wells (AIPHWs) is the most critical indicator of the success of the acidification. Currently, most previous works studied AIPHW based on the point source method. However, an inherent singularity exists in the point source solution, and hence, the calculation speed is too slow or the solution does not converge. To solve this problem, a semi-analytical model (coupling the wellbore flow model and reservoir seepage model) by the volumetric source method is presented to determine AIPHW in carbonate reservoirs. In this new coupled model, the permeability heterogeneity, formation contamination, acid-induced wormhole formation, and wellbore pressure drop are all considered. The results of the validations show that the results from the proposed method match well with the model results from the literature. Then, the effects of the acid injection flowrate, acid injection time, and permeability heterogeneity on the AIPHW are studied. According to the sensitivity analysis, we find that the disequilibrium degree of AIPHW becomes stronger as acid injection flowrate increases, acid injection time increases, and permeability heterogeneity coefficient increases. This study provides a guide for the design of horizontal well acidification and the evaluation of acid treatments of horizontal wells in carbonate reservoirs.

2013 ◽  
Vol 827 ◽  
pp. 239-243
Author(s):  
Jia Ming Zhang ◽  
Xiao Dong Wu ◽  
Zhuang Zhang ◽  
Han Han Zhang ◽  
Jia Zhang ◽  
...  

In the development of bottom water sandstone reservoir, the utilization of horizontal wells is economical and reliable but also can delay the bottom water coning and it has the advantages over the conventional vertical wells .The methods adopted in the past have methodological errors. This paper regards the reservoir flow and wellbore flow of horizontal well as a interactional system which considers the fluid friction, momentum change, the mixed interference of wellbore wall inflows and other complex factors and obtains Laplace space solution by using the Laplace transform to establish the coupled model of wellbore pressure drop calculation. It can provide more advanced means for reservoir engineering studies, well completion and production engineering design of horizontal wells on the conditions of bottom water reservoir.


2005 ◽  
Vol 73 (4) ◽  
pp. 598-609 ◽  
Author(s):  
Sourav Banerjee ◽  
Tribikram Kundu ◽  
Dominique Placko

In the field of nondestructive evaluation (NDE), the newly developed distributed point source method (DPSM) is gradually gaining popularity. DPSM is a semi-analytical technique used to calculate the ultrasonic field (pressure and velocity fields) generated by ultrasonic transducers. This technique is extended in this paper to model the ultrasonic field generated in multilayered nonhomogeneous fluid systems when the ultrasonic transducers are placed on both sides of the layered fluid structure. Two different cases have been analyzed. In the first case, three layers of nonhomogeneous fluids constitute the problem geometry; the higher density fluid is sandwiched between two identical fluid half-spaces. In the second case, four layers of nonhomogeneous fluids have been considered with the fluid density monotonically increasing from the bottom to the top layer. In both cases, analyses have been carried out for two different frequencies of excitation with various orientations of the transducers. As expected, the results show that the ultrasonic field is very sensitive to the fluid properties, the orientation of the fluid layers, and the frequency of excitation. The interaction effect between the transducers is also visible in the computed results. In the pictorial view of the resulting ultrasonic field, the interface between two fluid layers can easily be seen.


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