Investigation on flow regimes and non-Darcy effect in pressure test analysis of horizontal gas wells

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.

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A New Method of Negative Expiratory Pressure Test Analysis Detecting Upper Airway Flow Limitation To Reveal Obstructive Sleep Apnea

CHEST Journal ◽

10.1378/chest.128.4.2159 ◽

2005 ◽

Vol 128 (4) ◽

pp. 2159-2165 ◽

Cited By ~ 10

Author(s):

Giuseppe Insalaco ◽

Salvatore Romano ◽

Oreste Marrone ◽

Adriana Salvaggio ◽

Giovanni Bonsignore

Keyword(s):

Obstructive Sleep Apnea ◽

Sleep Apnea ◽

Upper Airway ◽

New Method ◽

Flow Limitation ◽

Test Analysis ◽

Obstructive Sleep ◽

Pressure Test

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Pressure Drop Characteristics and Reserves Calculation Method of Gas Reservoir of Multi-Layer Unconsolidated Sandstone

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.616-618.864 ◽

2012 ◽

Vol 616-618 ◽

pp. 864-869

Author(s):

Pang Jin ◽

Hong Liu ◽

Xiao Lu Wang

Keyword(s):

Pressure Drop ◽

Formation Pressure ◽

Accurate Calculation ◽

Gas Wells ◽

Gas Reservoir ◽

Gas Field ◽

Practical Result ◽

Straight Line ◽

Sand Control ◽

Pressure Test

Taking Sebei gas field as an example, this paper sorts hydrostatic pressure test data over the years and summarizes the reasons that the formation pressure drop curve generates a straight line, up-warping and recurvation from the perspective of water invasion, perforation adding, layer adjusting, sand burying, and sand control as well as inter-layer interference and inter-well interference, with typical wells analyzed and explained. On this basis, two kinds of mass balance correction models which have taken the offset of the pressure drop curve into account are proposed to calculate the dynamic reserves of gas wells with different offset shapes of pressure drop curves. Practical result shows the simple concept and strong practicality of this method, which provides an effective method for the accurate calculation of dynamic reserves of such gas reservoir.

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