Challenges of Pressure Transient Analysis PTA: Uncertainty Assessment and Pitfalls in Well Test Analysis-How Much Confidence Does a PTA Interpretation Has?

2020 ◽  
Author(s):  
Mustafa Cobanoglu ◽  
Ibrahim Shukri
Keyword(s):  
Transient Analysis ◽  
Uncertainty Assessment ◽  
Well Test ◽  
Well Test Analysis ◽  
Test Analysis ◽  
Pressure Transient Analysis ◽  
Pressure Transient

scholarly journals Numerical Well Test Analysis for Polymer Flooding considering the Non-Newtonian Behavior

2015 ◽  
Vol 2015 ◽  
pp. 1-10
Author(s):  
Jia Zhichun ◽  
Li Daolun ◽  
Yang Jinghai ◽  
Xue Zhenggang ◽  
Lu Detang
Keyword(s):  
Transient Response ◽  
Polymer Concentration ◽  
Shear Thinning ◽  
Polymer Flooding ◽  
Oil Field ◽  
Well Test ◽  
Well Test Analysis ◽  
Test Analysis ◽  
Pressure Transient ◽  
Thinning Effect

Well test analysis for polymer flooding is different from traditional well test analysis because of the non-Newtonian properties of underground flow and other mechanisms involved in polymer flooding. Few of the present works have proposed a numerical approach of pressure transient analysis which fully considers the non-Newtonian effect of real polymer solution and interprets the polymer rheology from details of pressure transient response. In this study, a two-phase four-component fully implicit numerical model incorporating shear thinning effect for polymer flooding based on PEBI (Perpendicular Bisection) grid is developed to study transient pressure responses in polymer flooding reservoirs. Parametric studies are conducted to quantify the effect of shear thinning and polymer concentration on the pressure transient response. Results show that shear thinning effect leads to obvious and characteristic nonsmoothness on pressure derivative curves, and the oscillation amplitude of the shear-thinning-induced nonsmoothness is related to the viscosity change decided by shear thinning effect and polymer concentration. Practical applications are carried out with shut-in data obtained in Daqing oil field, which validates our findings. The proposed method and the findings in this paper show significant importance for well test analysis for polymer flooding and the determination of the polymer in situ rheology.

scholarly journals An approximation of behind-casing hydraulic conductivity between layers from transient pressure analysis

DYNA ◽  
2019 ◽  
Vol 86 (210) ◽  
pp. 108-114
Author(s):  
Freddy Humberto Escobar ◽  
Angela María Palomino ◽  
Alfredo Ghisays Ruiz
Keyword(s):  
Hydraulic Conductivity ◽  
Transient Analysis ◽  
Test Interpretation ◽  
Well Test ◽  
Transient Pressure ◽  
Pressure Transient Analysis ◽  
Pressure Transient ◽  
Transient Pressure Analysis ◽  
Pressure Analysis

Flow behind the casing has normally been identified and quantified using production logging tools. Very few applications of pressure transient analysis, which is much cheaper, have been devoted to determining compromised cemented zones. In this work, a methodology for a well test interpretation for determining conductivity behind the casing is developed. It provided good results with synthetic examples.

scholarly journals A Two-Phase Numerical Model of Well Test Analysis to Characterize Formation Damage in Near-Well Regions of Injection Wells

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jia Zhang ◽  
Shiqing Cheng ◽  
Shiying Di ◽  
Zhanwu Gao ◽  
Rui Yang ◽  
...  
Keyword(s):  
Flow Regimes ◽  
Transient Behavior ◽  
Formation Damage ◽  
Well Test ◽  
Well Test Analysis ◽  
Injection Wells ◽  
Two Phase ◽  
Test Analysis ◽  
Specific Flow ◽  
Pressure Transient

Formation damage usually occurs in near-well regions for injection wells completed in offshore oilfields under the development of line drive patterns. However, current works on characterizing the damage by well test analysis were basically focused on using single-phase analogy to solve two-phase flow issues, resulting in errors on the diagnosis and interpretation of transient pressure data. In this paper, we developed a two-phase model to simulate the pressure transient behavior of a water injection well in a multiwell system. To solve the model more efficiently, we used the finite volume method to discretize partially differential flow equations in a hybrid grid system, including both Cartesian and radial meshes. The fully implicit Newton-Raphson method was also employed to solve the equations in our model. With this methodology, we compared the resulting solutions with a commercial simulator. Our results keep a good agreement with the solutions from the simulator. We then graphed the solutions on a log-log plot and concluded that the effects of transitional zone and interwell interference can be individually identified by analyzing specific flow regimes on the plot. Further, seven scenarios were raised to understand the parameters which dominate the pressure transient behavior of these flow regimes. Finally, we showed a workflow and verified the applicability of our model by demonstrating a case study in a Chinese offshore oilfield. Our model provides a useful tool to reduce errors in the interpretation of pressure transient data derived from injection wells located in a line drive pattern.

Pressure Transient Analysis for Fracture-Cavity Carbonate Reservoirs with Large Scale Fractures-Caves in Series Connection

2021 ◽  
pp. 1-20
Author(s):  
Cuiqiao Xing ◽  
Hongjun Yin ◽  
Hongfei Yuan ◽  
Jing Fu ◽  
Guohan Xu
Keyword(s):  
Transient Analysis ◽  
Carbonate Reservoir ◽  
Carbonate Reservoirs ◽  
Test Model ◽  
Well Test ◽  
Analysis Model ◽  
Pressure Transient Analysis ◽  
Linear Flow ◽  
Pressure Transient ◽  
Well Test Model

Abstract Fractured vuggy carbonate reservoirs are highly heterogeneous and non-continuous, and contains not only erosion pores and fractures but also the vugs. Unfortunately, the current well test model cannot be used to analyze fractured-vuggy carbonate reservoirs, due to the limitations of actual geological characteristics. To solve the above-mentioned problem, a pressure transient analysis model for fracture-cavity carbonate reservoir with radial composite reservoir that the series multi-sacle fractures and caves exist and dual-porosity medium (fracture and erosion pore) is established in this paper, which is suitable for fractured vuggy reservoirs. Laplace transformation is used to alter and solve the mathematical model. The main fractures' linear flow and the radial flow of caves drainage area are solved by coupling. The pressure-transient curves of the bottomhole have been obtained with the numerical inversion algorithms. The typical curves for well test model which has been established are drawn, and flow periods are analyzed. The sensitivity analysis for different parameters is analyzed. The variation characteristic of typical curves is by the theoretical analysis. With the increasing of fracture length, the time of linear flow is increased. While the cave radius is the bigger, the convex and concave of the curve is the larger. As a field example, actual test data is analyzed by the established model. An efficient well test analysis model is developed, and it can be used to interpret the actual pressure data for fracture-cavity carbonate reservoirs.

Transient Pressure Analysis of Wells Intercepted by Partially Penetrating Finite Conductivity Hydraulic Fractures

2013 ◽  
Vol 446-447 ◽  
pp. 479-485
Author(s):  
De Tang Lu ◽  
Qing Xie ◽  
Cong Niu ◽  
Lei Wang
Keyword(s):  
Hydraulic Fracture ◽  
Transient Analysis ◽  
Contradictory Result ◽  
Hydraulic Fractures ◽  
Finite Conductivity ◽  
Well Test ◽  
Analysis Model ◽  
Transient Pressure ◽  
Pressure Transient Analysis ◽  
Pressure Transient

Most current pressure transient analysis techniques of hydraulically fractured wells are based on the fully penetrating assumption, which assumes equal thickness of hydraulic fracture and the formation. However, field application show that the fractures thickness can be shorter than the thickness of formation, which leads to vertical flow into the fracture. Thus applying the thickness equality assumption of current well test models to a partial penetrating fracture may give contradictory result. Further, there are very few studies concerning pressure transient analysis of partial penetrated wells. So it is important to develop analysis model and procedure to this type of fracture. In this paper, we presented an analytical model for partially penetrating hydraulic fracture in isotropic systems, along with the assumption that fracture is finite conductive. This model is then applied in the analysis of field production data, which verified validity of this new model.

scholarly journals Pressure Transient Analysis for a Horizontal Well in Heterogeneous Carbonate Reservoirs Using a Linear Composite Model

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Yong-Gang Duan ◽  
Ke-Yi Ren ◽  
Quan-Tang Fang ◽  
Ming-Qiang Wei ◽  
Morteza Dejam ◽  
...  
Keyword(s):  
Transient Analysis ◽  
Horizontal Well ◽  
Flow System ◽  
Carbonate Reservoirs ◽  
Dual Porosity ◽  
Well Test ◽  
Rock Matrix ◽  
Pressure Transient Analysis ◽  
Pressure Transient ◽  
Type Curves

Carbonate reservoirs usually have strong anisotropy. Oil and gas recovery from fractured reservoirs is highly challenging due to complicated mechanisms involved in production from these reservoirs. A horizontal well completed in these reservoirs may extend through multiple zones, including homogeneous, dual-porosity, and triple-porosity formations. Traditional well test models assume that the entire length of a horizontal or multilateral well remains in the same formation with uniform properties. A well test model for pressure transient analysis of horizontal wells extending through a carbonate reservoir consisting of natural fractures, rock matrix, and vugs with different properties is presented in this study. The focus of this study is on dual-porosity (fracture-matrix) and triple-porosity (fracture-matrix-vug) reservoirs, considering the pseudosteady interporosity flows from rock matrix and vugs into fractures. A multizone triple-porosity model was established and solved by using the point source function, Green’s function, and coupling of multiple reservoir sections. The corresponding type curves were developed, and sensitivity analysis was carried out. The type curves of flow stage division reveal that a horizontal well traversing a three-section reservoir including homogeneous, dual-porosity (fracture-matrix)/triple-porosity (fracture-vug-matrix), and homogeneous sections identifies the stages of pseudosteady interporosity flow from matrix and vug into fracture, fracture pseudoradial flow, system linear flow, system pseudoradial flow, and pseudosteady flow occur in sequence. The greater the difference of permeability between the dual-porosity/triple-porosity section and the two homogeneous sections, the more obvious the interporosity flow on the pressure derivative curve. This approach satisfies the need for pressure transient analysis for a horizontal well that traverses two or more regions with distinct properties in heterogeneous carbonate reservoirs.

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