The Study of Bottom-hole Pressure and Flow Rate Behaviors Affected by Formation Boundary and Anticline Structure of a Reservoir

Autor: Ming-HaoWu, 吳珉豪
Rok vydání: 2013
Druh dokumentu: 學位論文 ; thesis
Popis: 101
An oil reservoir’s area is related to the original oil in place, and wellbore flow-pressure and flow-rate are affected by reservoir boundaries. The literature pays little attention to the effect of the formation structure on wellbore flow-pressure and flow-rate. The boundary effect time of flow-pressure and flow-rate data and radius of investigation are fundamental for understanding the distance from wellbore to boundary and how much original oil there was. We aimed to (1) determine whether reservoir boundaries and formation structure affected wellbore flow-pressure and flow-rate, and (2) estimate the distance from the wellbore to the reservoir boundaries by analyzing the flow-pressure and flow-rate. We used a flat model of a finite reservoir (with different boundary radii) that simulated bottom-hole flow-pressure in a case of constant production, and flow-rate in a case of constant pressure. The simulation results were validated by analytical solutions from the literature. Based on the validated model, variable depths for each grid and for mapping the anticline structure were part of the structure model. Similarly, the structure model was set up to calculate bottom-hole flow-pressure and flow-rate. The results were compared with the bottom-hole flow-pressure and flow-rate of the structure model with the flat model. We used the intersection method and well-test analysis software to analyze the bottom-hole flow-pressure and flow-rate and to calculate the distance from the wellbore to the reservoir boundary. Using the same reservoir volume for the flat and structure models, we found that (1) with or without an anticline structure, the result of the structure effect on bottom-hole flow-pressure, flow-rate, and radius of investigation was very slight. Therefore, we could ignore the effect of reservoir structure and use only the flat model as the field model; and that (2) by analyzing the effect of the boundaries on flow-pressure and flow-rate data, and then calculating the boundary radius using the radius-of-investigation equation, the distance from the wellbore to the reservoir boundaries could be determined. The calculated and actual radii of the boundary were close. The accuracy of the radius calculated by analyzing the flow-pressure data using the intersection method was more accurate than using the visual deviation point. Analyzing the flow-rate data using the visual deviation point between the infinite-acting and finite-flow period causes a judgment error and affects the calculated distance from the wellbore to the boundary.
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