Petroleum engineering has been developed since the beginning of the 19th Century. The following images demonstrates petroleum technology milestone from 1848 – 1959. This is the first part of this series and more to come.
1848:World’s First Oil Well – Major Aleveev drills the world’s first oil well at Baku, Azerbaijan using a primitive cable-tool drilling technique which originated in ancient China.
In order to properly design a completion, reservoir rock and fluid properties must be carefully taken into account because they directly influence on equipment selection. Reservoir properties (rock and fluid properties) which must be considered are as follows;
Permeability (k)
Low permeability formation may require fracturing operation to enhance production. The completion for tight formations must be able to withstand pumping pressure and allow fracking fluid and proppant to flow through.
Formation Strength
Unconsolidated formations are required to complete a well with a sand control completion; thus, a well can be produced without any damage to downhole and surface equipment.
Formation Pressure
Reservoir pressure directly affects the pressure rating on all completions because all components must be able to work under reservoir condition. What’s more, formation pressure will affect how much flow of the well can produce.
Formation Temperature
High reservoir temperature will quickly degrade some components, especially elastomer, and this will result in well integrity issues due to pressure leakage. This is one of the critical concerns in selecting the right equipment to work under high temperature conditions. Continue reading
Mechanical properties of material are one of the most important basic concepts in a well design and this section will briefly discuss about key mechanical properties and their applications. Furthermore, there is a discussion about effect of corrosion on the mechanical performance of load carrying components.
Basic mechanical properties are as follows;
Hardness
Hardness is a resistance of materials to permanent deformation and is sometimes referred to a resistance to abrasion or scratching. The greater of the hardness, the harder it is for the materials to deform. The application of hardness is to inspect if materials have been properly treated during a heat treatment process. The comparison between the actual hardness and the standard hardness of materials will show whether the current batch of material is proper and suitable for use or not.
Strength
Strength of material is an ability to work within a load without failure of the material. Tensile and yield strength are critical properties in terms of material strength.
Tensile Strength
Tensile strength or ultimate tensile strength is the maximum stress on an engineering stress-strain curve. At this point, materials are plastically deformed but they may not be broken apart yet depending on types of materials. Continue reading
This example will demonstrate how to determine the compressibility factor (z) for gas with CO2 and H2S. As it is described in the article,Determine Compressibility of Gases , it states that gas with CO2 and H2S must be corrected. This is similar to a normal method for determining z-factor but it is required some correction. Please follow the steps below;
Gas component is shown in Table 1
Table 1 – Gas Component
Reservoir pressure = 6,000 psia
Reservoir temperature = 190 F Continue reading
This example will demonstrate how to calculate the compressibility of real gas in order to determine gas density and specific gravity at a specific condition.
Calculate the following based on the given condition:
1) Density of this gas under the reservoir conditions of 7,500psia and 220ºF,
2) Specific gravity of the gas.
Gas component is shown in Table 1
Table 1 – Gas Component
Average density of air = 28.96 lb/cu-ft
Table 2 – Critical Pressure and Temperature
Note: critical pressure and temperature can be found from this link – https://www.drillingformulas.com/determine-compressibility-of-gases/
Pc’ = Σyipci = 660.5 psia
Tc’ = ΣyiTci = -46.2 F = -46.2 +460 F = 413.8 R
Table 3 – Pc’ and Tr’ by Kay’s Rule
Tr = T ÷Tc
Tr = (220+460) ÷ (-46.2+460)
Tr = 1.64
Note: temperature must be in Rankin.
Rankin = Fahrenheit + 460
For the critical temperature calculation, it can be converted the critical temperature from F to R before calculating Tc’. This will still give the same result.
Pr = P ÷ Pc
Pr = 7500 ÷ 660.5 = 11.4
z = 1.22
Figure 1-z-factor from the Standing and Katz Chart
Average Molar Mass = Σyi×Mi = 22.1 lb
Table 4 – Average Molar Mass of Gas
Gas Density = 18.6 lb/cu-ft
SG = Gas Density ÷ Air Density
SG = 18.6 ÷ 28.96
SG = 0.64
Summary:
The answers for this answer are listed below;
Gas Density = 18.6 lb/cu-ft
SG = 0.64
We wish that this example will help you understand to determine z-factor and use it to calculate any related information.
References
