An Improved Method To Determine Horizontal Well Productivity At Steady State

An Improved Method To Determine Horizontal Well Productivity At Steady State

Table Of Contents

Titlepage.I

Fidelity. III

Table Of content.iv

List Of tables.vii

List Of figures.viii

Acknowledgement. X

title. XII

Chapter One

Preface.1

Background Of Study.3

Operations Of Horizontal Wells 4

Advantages Of Horizontal Wells…5

Disadvantages Of Horizontal Wells..5

Flux Performance Relationship. 5

Problem Statement…5

Exploration Ideal…6

Exploration Question….6

Defense Of This Study..7

Compass Of Study.8

Points/ Objects.14

Chapter Two. 15

Literature Review.. 15

Productivity Indicator..18

Vertical Well Productivity.19

BORISOV ’S MODEL…20

GIGER ’S MODEL.21

JOSHI ’S MODEL.22

RENARD AND DUPUY MODEL..23

ELGAGHAD, OSISANYA AND TIAB MODEL.24

BABU AND ODEH(PSEUDO-STEADY STATE) MODEL 25

CHAPTER THREE.. 23

MODEL DESCRIPTION.. 23

Individual Subcaste And Boundary Characterization 27

Chapter Four.31

Analysis Of Result.31

Chance Divagation Of Results..32

Discussion.32

Chapter Five…55

Conclusion.. 55

Recommendation.73

References..56

Excursus..59

List Of Tables

Table 4- SEQ Table* ARABIC 1 Comparison of Productivity indicator Result

Table 1A Variation of Productivity Index with Changing Well Length

Table 1B Comparison of Vertical and Horizontal Well Productivity at colorful Reservoir Consistence

List Of Figures

Figure1- 1 A schematic of a perpendicular well drilled vertical to the coverlet aeroplane , and a vertical well drilled resemblant to the coverlet aeroplane .

Figure 1- 2 Vertical well following thin bed conformation.

Figure 1- 3 use of vertical well to minimize Water and/ or Gas coning

Figure 1- 4 crossroad of Fractures

Figure SEQ Figure* ARABIC 1- 1 Division of 3D vertical well problem into 2D problems

Figure 2- 2 Transformation of Eclipse into Unit Circle

Figure 2- 3 Babu and Odeh Physical Model

Figure 3- 1 Reservoir Model with completely piercing well

Figure 3- 2 Model Boundaries conditions

Figure 3- 3 Flow figure in the Reservoir

Figure 4- 1 Plot of Productivity Index against Well Length

Figure 4- 2 Plots of Productivity Index against Reservoir Thickness

Figure 4- 3 The effect of Reservoir Thickness on Productivity rate

Title

A, drainage area of vertical well, ft2

a, force range

a = partial major axis of drainage cirque, ft

Bo, oil painting conformation volume factor, rb/ STB

b, extension of drainage volume of vertical well in y- direction, ft

C, unit conversion factor

CH, geometric factor in Babu and Odeh’s model

D, wellbore periphery

h, force consistence, ft

Iani, permeability anisotropy, dimensionless

J, productivity indicator, STB/ day/ psi

k, effective permeability, md

kH, vertical permeability, md

kV, perpendicular permeability, md

L, vertical wellbore length, ft

L1/ 2, half length of vertical wellbore, ft

p, force pressure, psi

pe, force pressure at boundary, psi

pi, original pressure, psi

pwf, bottomholeflowing pressure, psi

qo, oil painting product rate, STB/ day

re, compass of external boundary of the force, ft

rw, wellbore compass, ft

s, skin factor, dimensionless

sR, partial penetration skin factor, dimensionless

Greek symbol

ε, relative pipe roughness

Φ, flow implicit

ϕ, porosity

θ, wellbore inclination

µ, density

ρ, viscosity

Abstract

As the petroleum assiduity continues to witness advances and progress in drilling ways, the use of vertical well in field development has been adding veritably fleetly throughout the oil painting assiduity. It becomes thus important to adequately determine the performance of vertical wells.

The being styles available to determine vertical well productivity at steady state requires complex fine analysis and are delicate to develop. In the course of this work, a new system was developed using simple logical styles. Results attained by this new system were compared to that gotten from formerly established styles of Borisov( 1964), Giger( 1984) and Joshi( 1988). The major ideal of this work is to present a simple and effective means to estimate the performance of vertical wells. An excel distance was also created in the course of this design to calculate and compare productivity indicator gotten from the colorful system. The spread distance also enable me carry out perceptivity analysis of the results gotten by varying crucial parameters.

Chapter 1

Preface

The major purpose of a vertical well is to enhance force contact and thereby enhance well productivity. A vertical well is drilled resemblant to the force coverlet aeroplane . In other words, a perpendicular well is drilled vertical to the coverlet aeroplane ( see fig1.1).

Figure 1- 1

still, also a conventional perpendicular well will be drilled resemblant to the coverlet aeroplane and in the theoretical sense it would be vertical well, If the force coverlet aeroplane is perpendicular. The ideal then’s to cross multiple pay zones Vertical wells have come popular for producing oil painting and gas budgets in numerous regions around the world. The objects of vertical wells include adding oil painting and gas product, turning anon-commercial oil painting or gas force into a marketable force and controlling severe coning problems. Due to the fact that vertical wells can enhance force recovery, they should be taken into consideration when planning a field development. While vertical wells are generally more precious to drill than perpendicular wells, they frequently reduce the total number of wells needed in a force development. As an adding number of vertical gas wells are drilled, the need for a quick and dependable system to estimate the pressure- rate geste of these wells is important to optimize well performance and make functional opinions. A dependable and simple logical and empirical relationship will give masterminds a fashion to assess the performance of vertical wells previous to bearing expansive and frequently time- consuming simulation studies to model the well-conditioned geste .

flux performance relationship( IPR) is a pressure- rate connections used to prognosticate performance of oil painting and gas wells. There’s a direct relationship when the force is producing at pressure above bubble point pressure i.e. when Pwf is lesser or equal to bubble point pressure. A wind is attained at Pwf less than bubble point pressure. The direct form of an IPR represents the Productivity Index( PI) which is the antipode of the pitch of the IPR. Vertical oil painting well IPR also depends on the inflow condition that’s whether it’s flash, steady orpseudo-steady state inflow, which is determined by force boundary condition. As the use of vertical and multinational wells is adding in ultramodern exploitation strategies, flux performance connections for vertical wells are demanded. The ideal of this work is to develop logical equation and IPRs for vertical oil painting wells in steady state conditions that are easy to apply.

Background Of Study

Vertical wells are high- angle wells( with an inclination of generally lesser than 85ᵒ) drilled to enhance force performance by placing a long wellbore section within the force. There was fairly little vertical drilling exertion before 1985. A variety of configurations of drilled wells have come to be characterized as vertical wells or drain holes. Drainholes are short length wellbores drilledpre-existing perpendicular wells in order to enhance product. These extend between 100 and 500ft. in either direction. Vertical wells on the other hand, involve the drilling of new wells and are generally 1000ft or more in length.

The use of vertical wells to increase the area of communicated force dates back to the early 1940’s. Feasibility of creating similar armature to drain a force more, has been proven for a long time but the profitable viability of such a process didn’t establish itself until recent times. This has been largely due to titanic advances in drilling, surveying and interpretation technologies.

The following are fields around the world that have been successfully drilled and are producing through vertical wells

Austin Chalk conformation Texas

Spraberry Tread West Texas

Pearsall Field South Texas

Okoro Oilfield Niger Delta, Nigeria

Operations Of Vertical Well

Vertical wells are substantially applied in the ensuing areas;

1. To Exploit Thin Oil and Gas Zone Budgets A vertical wells reflects an increased area of contact of the well with the force when compare to perpendicular wells in a thin pay zone. As a result of this increased area of contact, there’s an increase in product from vertical wells.

Figure 1- 2 Vertical well following thin bed conformation

2. Reduction of Coning A vertical well is anticipated to have a reduced pressure drawdown when compared to a perpendicular well for a analogous product position. This reduced drawdown pressure is anticipated to delay the onset of water( gas) advance. oil painting recovery is anticipated to be high except in cases where the well-conditioned intersects fractures or zones of high permeability which could affect in early water( gas) advance.

Figure 1- 3 use of vertical well to minimize Water and/ or Gas coning

3. To cross fracture in a naturally fractured force in order to drain them effectively.

Figure 1- 4 crossroad of Fractures

4. In Enhance Oil Recovery( EOR) operations, especially in thermal EOR. Vertical well provides a large force contact area and thus enhances injectivity of an injection well. It also helps to increase the reach effectiveness.

Advantages Of Horizontal Wells

1. bettered reach effectiveness in pattern flood tide situations.

2. Reduction in coning. Lower drawdown for the same inflow rate as perpendicular wells, causes stable interface movement delaying the advance of unwanted fluids.

3. Reduced fluid rapidity around wellbore thereby reducing the circumstance of turbulent inflow.

4. Smaller number of wells is needed for field development.

5. More access to insulated zones and exploiting graveness drainage medium effectively.

6. Drilling relief wells for blow out forestallment.

7. penetrating untapped portion of a force under constrained drilling conditions( coastal platforms).

DISADVANTAGES OF HORIZONTAL WELLS

1. It isn’t suitable for thick budgets.

2. Completion and Stimulation technology has not been perfected yet.

3. still, the advance of unwanted fluids can be accelerated, If natural fractures connect the aquifer or gas cap.

4. Not suitable in low perpendicular permeability situations.

5. Advanced cost of drilling per well.

6. Hole problems encountered while drilling can be a serious debit.

FLUX PERFORMANCE RELATIONSHIP( IPR)

The relation between product rate( q) and flowing wellbore pressure( pwf) over the practical range of product conditions, this relation is generally known as flux performance relationship( IPR). Productivity indicator is a measure of the capability of a well to produce. It’s the rate of the liquid inflow rate to the pressure drawdow