Journal of Petroleum Research & Studies

A finite element model was constructed to predict inclination tendency for multistabilizer rotary BHA in three dimensions, static condition. The bottom hole assembly was idealized with beam element capable of resisting axial forces, bending moments about the two principal axes, and twisting moments about its centroidal axis. Bit and stabilizer were treated as contact point and restricted from movement in all directions. Each element is loaded with gravity and normal contact forces.
Model validation showed closer agreement between the model and Jiazhi's method (analytic) for slick, single, and two stabilizers BHA, compared to Akgun results. Predictions with finite element model showed that for building assembly, the weight on bit had small effect on bit side force especially in high angle wells. Also inclination tendency (building, dropping) would depend on position of the stabilizer, diameter of drillcollar behind the bit, and number of stabilizers.

Even drill bits cost are about 3-5% of the total drilling budget, but bits performance affects as much as 60% of the drilling cost[1] that would explain the necessity of continuous studying and developing this tool to improve drilling performance. Unfortunately, most of Iraqi oil fields managed by states companies does not give the proper attention for bits optimization issues, that would cause insufficient bits used to drill a certain formation due to the absence of a serious dealing with formation hardness and other bit selection criteria while designing, or making bits purchases contracts, or they would satisfy by a minimum rates of penetration.
Unfortunately, the bit selection issue is matched the optimum selection for the drilling parameters issue, it is a matter of tri and error [2].
In this study, a southern Iraqi oil field located in Basra region have been selected to optimize the bits used to drill its wells.
Summarizations of bits selection methods have been reviewed, advantages and disadvantages of possibility to applicant those methods in Basra regions have been introduced. A proper algorithm for selecting bits in Iraq was also presented. An economic evaluation for a different bit type's strategies used to drill holes of Mishrif wells in Basra oil fields region also discussed.
This study improve that using bits holding the IADC code 425, M322 PDC bit with 6th blades and 16mm cutter size and M323 PDC bit with 5th blades and 6mm cutter size are the optimum selection to drill the surface, intermediate, and production holes consequently.
This study is applicable to all Iraqi oil fields and especially for Basra region oil fields due to its large analogous on the lithology column and the drilling problems may combined the drilling operations among the different oil fields in this area.

Chlorodifluoromethane is used as pure or in mixture for refrigeration (medium-high temperatures). It is also used as a blowing agent for extruded polystyrene and polyurethane foams and a component in sterilant gas mixtures. A new generalized correlation for the physical and psychometric properties of liquid Chlorodifluromethane as a function to temperature are introduced, Equation (1). The new correlation was statistically compared with those previously presented and found to be :

… (1)
Where :
A, B, C and D are the property constants,
T is the temperature in degrees centigrade.

Carbon steel is a major metal used in manufacturing of the equipments used in petroleum industry and it is subject to different operating conditions causing various corrosion attacks. Corrosion of carbon steel in sodium sulphate solution (Na2SO4) under flow conditions was investigated using rotating cylinder electrode (RCE) for a range of rotation velocity (0 – 2000 rpm) and temperatures (32 - 52 oC). The corrosion rate was determined by using both weight loss method and electrochemical polarization technique (limiting current density). Different salt concentrations were investigated ranged from 0.01 to 0.4 M. The effect of time (or corrosion product formation) and the effect of oxygen concentration through air bubbling in the solution were also investigated and discussed. The results showed that increasing rotational velocity leads to a considerable increase in the corrosion rate represented by limiting current density. The corrosion rate had unstable trend with salt concentrations and temperature. Generally, the corrosion rate decreased appreciably with time due to the formation of corrosion product layer depending on rotational velocity, temperature, and oxygen concentration. It was found that, air pumping through the salt solution leads to a considerable increase in the limiting current density (iL) depending on rotational velocity, temperature, and time.

A study has been done to represent the pressure changes along gathering system in pipelines transporting Iraqi's crude oils; the study is divided into four parts. The first part represents the calculations of pressure drop in pipelines transporting petroleum fluid from the well head to a gathering point. In this part, there is a two-phase flow (gas and liquid). The calculations of pressure change in this part depends upon determination of some properties such as liquid and gas density, liquid and gas viscosity, liquid hold up and friction factor.
Determining the liquid hold up and then pressure drop are achieved using two methods, the first method is modified Beggs and Brill correlation, depending on three assumed flow patterns. The second is Aziz et al. correlation, depending on three flow patterns also but are different to that of modified Beggs and Brill. While a method of Colebrook used in determination of two-phase friction factor. The results of two-phase flow calculations show that modified Beggs and Brill correlation (having error of 0.26%) better than Aziz et al. correlation (having error of 0.55%).
In the second part there are calculations of pressure change in liquid flow in a pipeline from the gathering point to the first stage of separators. In this part Colebrook correlation is used to determine the friction factor, Brill and Mukherjee method is used for calculation of pressure change.
Mukherjee and Brill method gave good results with respect to the pressure drop of flow in the axial pipeline after the gathering point of the actual field data. The third part deals with the networking in pipelines, types of gathering systems presented and discussed, the calculations of pressure change in a simple gathering system is studied. The fourth part discusses optimization techniques; Constrained Rosenbrock is used to find optimum pressure which gives favorable oil properties. They have been achieved with some assumptions; they are:
1. Minimum Produced gas oil ratio.
2. Minimum formation volume factor.
3. Maximum API gravity.
Finally, two computer programs are developed. Each program performs all the calculations of the four parts. The first program is developed using FORTRAN language, while the second is developed using Visual Basic language.

The present work aims to study the performance of Baffled bubble Column Reactor on homogeneous flow regime .Experiments were carried out to investigate the effect a surface active agent (type and concentration ) on Gas Hold-Up in Baffled bubble Column Reactor on with the border range of superficial gas velocity (0.001 -0.039 m/s). Ethanol and hexanol were used as surfactants in the present work. Also three types of baffles: perforated, circular and fin baffle were used. The results show that the gas hold up increases with increasing the concentration of the surfactants. The highest values of gas hold up were recorded in the presence of perforated baffle with 30% of ethanol-water and hexanol-water mixture.

In this research, the effect of soil resistivity on the sacrificial cathodic
protection of a pipeline steel of oil was studied. Sufficient sacrificial cathodic
protection could be obtained at various soil resistivty for different types of
anodes. High current output (2.98, 2.38 and 8.33 Amps) of Zn, Al and Mg
anodes respectively, are obtained at 25 ohms.cm soil resistivity. Simultaneous,
for the same conditions, low numbers and large weights of anodes are required
to satisfy protection.

In this study five oil solutions were used to measure the corrosion of the metal tank which was used. This tank is used to hold the oil productions and is made of an alloy called low carbon steel.
These solutions are Benzene, water associated with benzene, Gas oil, water associated with the gas oil, and water associated with the crude oil. A three sample were choosing of each solution and the average was taken in order to get a precise result. Also the study clear field that the danger is located in lowest part of the tank because of the existence of the water however, the specific gravity of water is greater than the specific gravity of the benzene and gas oil. For this reason we have to super water associated even though the loss of a product to increase the duty time and ageing of the used tank.