Relationship between Formation Water Rate,Equivalent Penetration Rate and Volume Flow Rate of Air in Air Drilling

Formation water invasion is the most troublesome problem associated with air drilling. However, it is not economical to apply mist drilling when only a small amount of water flows into wellbore from formation during air drilling. Formation water could be circulated out of the wellbore through increasing the gas injection rate. In this paper, the Angel model was modified by introducing Nikurade friction factor for the flow in coarse open holes and translating formation water rate into equivalent penetration rate. Thus the distribution of annular pressure and the relationship between minimum air injection rate and formation water rate were obtained. Real data verification indicated that the modified model is more accurate than the Angel model and can provide useful information for air drilling.

Improved Correlation for the Volume of Bubble Formed in Air-Water System

In order to address the bubble formation and movement in air-water two-phase flow,single bubble rising in stagnant water is experimentally studied by digital image processing.Bubbles are released individually from the submerged orifices with different diameters(1.81 mm,2.07 mm,2.98 mm,3.92 mm)at different detachment frequency.Images are recorded by a high-speed video camera and processed by digital image processing technique. The factors impacting the formed volume of bubble are discussed.The experimental results showed that a threshold of gas flow rate(400 mm 3 ·s- 1)divides the bubble formation into two regimes:the constant volume regime and the growing volume regime.Especially for the growing volume regime,the surface tension is taken into account.The bubble volume is consisted of two parts:the surface tension impacting part and the gas volume flow rate impacting part.An improved correlation for bubble volume prediction is developed for the two regimes and better coincidence with the experiment data than the previous models is obtained.

A New Theory for the Essence and Nature of Electron Charge

Charge is a fundamental physical property of matter that is responsible for its interactions with electromagnetic fields. The real nature and the essence of charge are unknown. In this paper, a new theory is presented to describe the nature and the essence of electric charge is formulated based on the vortex model of the electron which has a finite size and has an irrotational vortex structure. This theory and the vortex model of the electron enables us, for the first time, to describe the origin of bivalency, stability, quantization, equality of the absolute values of the bivalent charges, to derive a simple formulation to calculate the electric charge based on hydrodynamics without the use any constant. The difference between negative and positive charge, is revealed and the charged particles interactions are described. The electric charge is an expression of accelerated spherical mass per area reduced by the stiffness of the vacuum which has the units ε0 ML3/T2. The calculated results based on these equations comply accurately with the experimental results.

Peristaltic transport of Herschel-Bulkley fluid in a non-uniform elastic tube

The influence of elasticity on peristaltic transport of Herschel-Bulkley fluid in a tube of non-uniform cross-section is investigated.The exact solutions for flow quantities such as velocity,stream function,pressure gradient,and volume flow rate are derived.The relationship between flux and pressure difference is discussed.The effects of different pertinent parameters on variation of flux along the radius of the tube are analyzed through graphs.The results show that the yield stress and fluid behavior index has significant effect on flux variation of Herschel-Bulkley fluid in a non-uniform elastic tube.The effect of elastic parameters on flux variation is analyzed.Trapping phenomenon is presented graphically to understand the physical behavior of various parameters.In the absence of non-uniform parameter the present results are similar to the observations of Vajravelu et al.[19].