Characteristics of Dimensionless Pressure Gradients and Derivatives of Horizontal and Vertical Wells Completed within Inclined Sealing Faults

2021 ◽  
Author(s):  
A V Ogbamikhumi ◽  
E S Adewole
Keyword(s):  
Pressure Drop ◽  
Horizontal Well ◽  
Superposition Principle ◽  
Early Time ◽  
Pressure Gradients ◽  
Vertical Wells ◽  
Pressure Derivative ◽  
Vertical Well ◽  
Dimensionless Pressure ◽  
Horizontal And Vertical Wells

Abstract Dimensionless pressure gradients and dimensionless pressure derivatives characteristics are studied for horizontal and vertical wells completed within a pair of no-flow boundaries inclined at a general angle ‘θ’. Infinite-acting flow solution of each well is utilized. Image distances as a result of the inclinations are considered. The superposition principle is further utilized to calculate total pressure drop due to flow from both object and image wells. Characteristic dimensionless flow pressure gradients and pressure derivatives for the wells are finally determined. The number of images formed due to the inclination and dimensionless well design affect the dimensionless pressure gradients and their derivatives. For n images, shortly after very early time for each inclination, dimensionless pressure gradients of 1.151(N+1)/LD for the horizontal well and 1.151(N+1) for vertical well are observed. Dimensionless pressure derivative of (N+1)/2LD are observed for central and off-centered horizontal well locations, and (N+1)/2 for vertical well are observed. Central well locations do not affect horizontal well productivity for all the inclinations. The magnitudes of dimensionless pressure drop and dimensionless pressure derivatives are maximum at the farthest image distances, and are unaffected by well stand-off for the horizontal well.

Flow Behavior of Horinzontal Well Cmpleted within Two Sealing Fauts Inclined at Right Angle

2021 ◽  
Author(s):  
Johnson Johnson ◽  
Ezizanami Adewole
Keyword(s):  
Horizontal Well ◽  
Flow Behavior ◽  
Superposition Principle ◽  
External Boundary ◽  
Pressure Derivative ◽  
Effective Work ◽  
Drainage Radius ◽  
Dimensionless Pressure ◽  
Well Location ◽  
Wellbore Pressure

Abstract At inception of a production rate regime, a horizontal well is expected to sweep oil within its drainage radius until the flow transients are interrupted by an external boundary or an impermeable heterogeneity. If the interruption is an impermeable heterogeneity or sealing fault, then the architecture of the heterogeneity must be deciphered in order to be able to design and implement an effective work-over or well re-entry to boost oil production from the reservoir. In this paper, therefore, the behavior of a horizontal well located within a pair of sealing faults inclined at 90 degrees is investigated using flow pressures and their derivatives. It is assumed that the well flow pressure is undergoing infinite activity, and each fault acts as a plane mirror. The total pressure drop in the object well is calculated by superposition principle. Damage and mechanical skin and wellbore storage are not considered. The main objective of our investigation is to establish identifiable signatures on pressure-time plots that represent infinite flow in the presence of adjacent no flow faults inclined at 90degrees. Results obtained show that the flowing wellbore pressure is influenced strongly by object well design, object well distance from each fault, and distance of each image from the object well. Irrespective of object well distance from the fault, there are three (3) images formed. Central object well location yields a square polygon, with two image wells nearer to the object well at equidistance from the object well, and the farthest image well to be 2d2. From the object well For off-centered object well location within the faults, a rectangular polygon is formed, with each image at a different distance from one well to another. Dimensionless pressure and dimensionless pressure derivative gradients during infinite-acting flow are (4.6052/LD) and 2/LD, respectively for all well locations within the faults.

scholarly journals Pressure Analysis for Volume Fracturing Vertical Well considering Low-Velocity Non-Darcy Flow and Stress Sensitivity

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Zhongwei Wu ◽  
Chuanzhi Cui ◽  
Japan Trivedi ◽  
Ning Ai ◽  
Wenhao Tang
Keyword(s):  
Flow Regime ◽  
Stress Sensitivity ◽  
Darcy Flow ◽  
Transition Flow ◽  
Low Velocity ◽  
Pressure Derivative ◽  
Threshold Pressure Gradient ◽  
Vertical Well ◽  
Dimensionless Pressure ◽  
Volume Fracturing

In general, there is stress sensitivity damage in tight reservoirs and fractures. Furthermore, the flow in tight reservoirs is the low-velocity non-Darcy flow. Currently, few researches of pressure analysis for volume fracturing vertical well are conducted simultaneously considering the low-velocity non-Darcy flow and stress sensitivity. In the paper, a novel flow model of a volume fractured vertical well is proposed and solved numerically. Firstly, the threshold pressure gradient, permeability modulus, and experimental data are, respectively, utilized to characterize the low-velocity non-Darcy flow, matrix stress sensitivity, and fracture stress sensitivity. Then, a two-region composite reservoir is established to simulate the vertical well with volume fracturing. After that, the logarithm meshing method is used to discrete the composite reservoir, and the flow model is solved by the method of finite difference and IMPES. Finally, the model verification is conducted, and the effects of the low-velocity non-Darcy flow and stress sensitivity on the pressure and pressure derivative are analyzed. The six flow regimes are identified by the dimensionless pressure and pressure derivative curve. They are, respectively, the fracture linear flow regime, early transition flow regime, radial flow regime, crossflow regime, advanced transition flow regime, and boundary controlling flow regime. The stress sensitivity and threshold pressure gradient have a great effect on the dimensionless pressure and pressure derivative. With the increase of reservoir stress sensitivity, the pressure and pressure derivative are upward at the advanced transition flow and boundary controlling regimes. However, the pressure and pressure derivative are downward at the advanced transition flow and boundary controlling regimes when the fracture sensitivity increases. An increase in the threshold pressure gradient results in a high dimensionless pressure and pressure derivative. This work reveals the effects of low-velocity non-Darcy flow and stress sensitivity on pressure and provides a more accurate reference for reservoir engineers in pressure analysis when developing a tight reservoir by using the volume fracturing vertical well.

Theoretical Dimensionless Breakthrough Time of a Horizontal Well in a Vertically-Stacked Two-Layered Reservoir System with Varying Architecture Part II: Letter ‘B’ Architecture, Bottom Water Drive Mechanism

2011 ◽  
Vol 367 ◽  
pp. 385-392
Author(s):  
E. Steve Adewole
Keyword(s):  
Horizontal Well ◽  
Bottom Water ◽  
Water Movement ◽  
Horizontal Wells ◽  
Breakthrough Time ◽  
Individual Layer ◽  
Pressure Derivative ◽  
Drive Mechanism ◽  
Effective Work ◽  
Dimensionless Pressure

When a reservoir experiences water influx, the actual source of the water often cannot be ascertained with precision. Thus well work over measures to minimize the water may not be easy to fashion. Bottom water encroaches through the bottom of the reservoir and rises vertically, appearing in all the wells in the field at the same time, if the wells experience the same production histories. This further makes work over difficult, more so, if there are other external fluid influences akin to a top gas. However, if the arrival time is known, then factors affecting bottom water movement, with or without any other contiguous top gas, may be studied with a view to fashioning an effective work over to mitigate premature water arrival into the well. Horizontal wells are already known to delay encroaching water breakthrough time. For a cross flow layered reservoir completed with a horizontal well in each layer, flow dynamics will certainly be different from a single layer reservoir due to differences in individual layer, layers fluid, wellbore and interface properties and rate histories. In this paper, theoretical expressions for predicting dimensionless breakthrough times of horizontal wells in a two layered reservoir of architecture like letter ‘B’, experiencing bottom water drive mechanism of different patterns, with or without a top gas, are derived. The theoretical breakthrough times are based on dimensionless pressure and dimensionless pressure derivative distributions of each identified model. Twenty-seven (28) different models emerged as the total of the different models possible.

Type Curves for a Reservoir Subject to Active Bottom Water Drive

2013 ◽  
Vol 824 ◽  
pp. 373-378
Author(s):  
I. Eiroboyi ◽  
E. Steve Adewole
Keyword(s):  
Steady State ◽  
Bottom Water ◽  
Early Time ◽  
Dimensionless Time ◽  
Pressure Derivative ◽  
Test Analysis ◽  
Type Curves ◽  
Well Completion ◽  
Dimensionless Pressure ◽  
Large Pressure

The use of dimensionless pressure and dimensionless pressure derivative type curves has fully overcome the challenges experienced in the use of straight line methods and has brought about major successes in well tests analyses. Flow periods and reservoir boundary types are easily delineated and identified with the use of these curves. Furthermore, near wellbore characterization results are now more reliable. In this study, type curves for a reservoir subject to bottom water energy and a vertical well completion are developed to reveal specific signatures that can be used to achieve efficient pressure test analysis. Both early and late flow periods were considered for a wellbore of negligible skin and wellbore storage influences. Results obtained show that dimensionless pressures depart from infinite-acting behavior and attain steady state at dimensionless time of order proportional to the square of dimensionless reservoir thickness. Wellbore dimensionless radius affects dimensionless time of attainment of steady state inversely, which is rather accelerated by large fluid withdrawal rates (large pressure drawdown). On the other hand, dimensionless pressure derivatives show gradual collapse to zero after expiration of infinite flow. The rate of collapse is strongly affected by wellbore properties and pressure drawdown. Radial flow is generally characterized by a constant slope of 1.151 during which period the dimensionless pressure derivative gave a value of 0.5. Following assumption of negligible wellbore skin and storage, no early time hump is observed on dimensionless derivative curves.

scholarly journals Pressure distribution of a horizontal well in a bounded reservoir with constant pressure top and bottom

2020 ◽  
Vol 39 (1) ◽  
pp. 154-160
Author(s):  
J.J. Orene ◽  
E.S. Adewole
Keyword(s):  
Mathematical Model ◽  
Steady State ◽  
Pressure Distribution ◽  
Horizontal Well ◽  
Constant Pressure ◽  
Horizontal Wells ◽  
Minimum Time ◽  
Pressure Derivative ◽  
Dimensionless Pressure ◽  
Lateral Extent

The purpose of this study is to develop a mathematical model using Source and Green’s functions for a Horizontal Wells in a Bounded Reservoir with Constant Pressure at the Top and Bottom for the interpretation of pressure responses in the reservoir based on dimensionless pressure and pressure derivative. Reservoir and well parameters investigated revealed what sets of reservoir/ well parameters combination that will prolong infinite activity of the reservoir before steady state sets in. Results show that dimensionless lateral extent does not directly affect the dimensionless pressure and dimensionless pressure derivative for very short well lengths as used in this paper. Dimensionless pressure increases with reservoir pay thickness and delay the time for steady state conditions. In fact external fluid invasion is strongly affected by the size of the pay thickness, thus the minimum time for steady state period to set in is according to the relation TD ≥ LD/5. Keywords: Bounded, reservoir, steady-state conditions, horizontal well, constant pressure.

scholarly journals Pressure Drop Equations for a Partially Penetrating Vertical Well in a Circular Cylinder Drainage Volume

2009 ◽  
Vol 2009 ◽  
pp. 1-33
Author(s):  
Jalal Farhan Owayed ◽  
Jing Lu
Keyword(s):  
Pressure Drop ◽  
Circular Cylinder ◽  
Constant Pressure ◽  
Dimensional Space ◽  
Outer Boundary ◽  
Superposition Principle ◽  
Vertical Well ◽  
Drainage Volume ◽  
Partial Penetration ◽  
Line Sink

Taking a partially penetrating vertical well as a uniform line sink in three-dimensional space, by developing necessary mathematical analysis, this paper presents unsteady-state pressure drop equations for an off-center partially penetrating vertical well in a circular cylinder drainage volume with constant pressure at outer boundary. First, the point sink solution to the diffusivity equation is derived, then using superposition principle, pressure drop equations for a uniform line sink model are obtained. This paper also gives an equation to calculate pseudoskin factor due to partial penetration. The proposed equations provide fast analytical tools to evaluate the performance of a vertical well which is located arbitrarily in a circular cylinder drainage volume. It is concluded that the well off-center distance has significant effect on well pressure drop behavior, but it does not have any effect on pseudoskin factor due to partial penetration. Because the outer boundary is at constant pressure, when producing time is sufficiently long, steady-state is definitely reached. When well producing length is equal to payzone thickness, the pressure drop equations for a fully penetrating well are obtained.

The Effects of Reservoir Area Extent on the Performance of a Vertical Well in a Reservoir Subject to Bottom Water Drive

2015 ◽  
Vol 752-753 ◽  
pp. 790-795
Author(s):  
I. Eiroboyi ◽  
P.O. Obeta
Keyword(s):  
Steady State ◽  
Bottom Water ◽  
Maximum Pressure ◽  
Large Area ◽  
Pressure Derivative ◽  
Type Curves ◽  
Reservoir Area ◽  
Vertical Well ◽  
Flow Equations ◽  
Dimensionless Pressure

Reservoir performance can be understood from system type curves. The type curve gives vivid information about maximum pressure drops, magnitude of near wellbore effects, reservoir fluid and wellbore properties needed to ascertain the strength of available drive mechanism, maximum withdrawal rates and remaining fluid in real time. This paper investigates the effects of reservoir area extent on the performance of a reservoir, subject to active bottom water, when it is completed with a vertical well. Type curves of dimensionless pressures and dimensionless pressure derivatives were produced for various dimensionless values of area extent of the reservoir. These type curves were developed from solutions to flow equations using relevant source and Green’s functions. From the results, it can be observed that the larger the reservoir area extent, the larger the dimensionless pressure drop, the longer the time it takes to attain steady state. This is validated from the pressure derivative curve, which shows that reservoirs with large area extent are characterized by longer period of radial flow and subsequently delay in the attainment of steady state, thus prolonging the arrival of bottom water.

Comparison between Pressure Drop Profile of a Horizontal Well as a Water Injector and as an Oil Producer in a Five-Spot Waterflood Pattern

2007 ◽  
Vol 18-19 ◽  
pp. 265-270
Author(s):  
E. Steve Adewole ◽  
O.A. Olafuyi
Keyword(s):  
Pressure Drop ◽  
Horizontal Well ◽  
Mobility Ratio ◽  
Pressure Drops ◽  
Pressure Distributions ◽  
Dimensionless Pressure ◽  
Water Breakthrough

This paper compares the pressure drop profiles of both horizontal well producer and injector in a 5spot waterflood pattern. Dimensionless pressure distributions for each pattern were utilised. All computations were limited to conditions of unit mobility ratio; i.e., before water breakthrough condition. Results show that a normal 5-spot flood pattern, with a horizontal well producer, offers higher pressure drops, but early water breakthrough tendencies, than as an injector for the same reservoir and wellbore conditions. An inverted pattern, under the same conditions, produces clean oil for a longer time, before water breakthrough possibilities.

Evaluation of Inflow Performance of Multiple Horizontal Wells in Closed Systems

1999 ◽  
Vol 122 (1) ◽  
pp. 8-13 ◽  
Author(s):  
Suwan Umnuayponwiwat ◽  
Erdal Ozkan
Keyword(s):  
Horizontal Well ◽  
Transient Flow ◽  
Horizontal Wells ◽  
Vertical Wells ◽  
Well Pattern ◽  
Horizontal And Vertical Wells ◽  
Closed Systems ◽  
Inflow Performance

This work presents a model to investigate the inflow performance relationships (IPR) of horizontal and vertical wells in a multi-well pattern. The model can be used to compute the overall and individual well performances. It is shown that stabilized IPRs may not be sufficient for the evaluation of horizontal well performances due to prolonged transient flow periods. The results presented in this paper clearly indicate that inflow performance of wells in a multi-well pattern is a dynamic concept; and, especially in the prediction of future performances, dynamic rather than static IPR models should be used. [S0195-0738(00)00801-3]

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