Piedmont tectonic belts are rich of oil and gas resources, however the intense tectonic stress and broken formation may cause great drilling problems in piedmont structures such as borehole collapse, lost circulation and gas cutting. Through analysis of in situ stress properties, bedding structure and mechanical characteristics, wellbore instability mechanism was expounded from rock mechanics, ...

The article considers the issue of reducing the influence of clayless mud components on the filtration parameters of the reservoir. In the composition of such solutions, calcium carbonate of various fractions is often added as a weighting and colmatizing additive. It is generally accepted that weighting bridging agents are sufficiently inert substances and their addition does not affect the rhe...

In a study of a sediment core from the US Atlantic Coastal Plain (Ocean Drilling Program Site 174X-Millville), Wright and Schal-ler (1) claim to have resolved the onset of the Paleocene/Eocene carbon isotope excursion (CIE) across 13 y. Such a rapid change would require an enormous and instantaneous release of isotopically light carbon into the ocean/atmosphere, implicating comet impact. The cl...

When drilling an oil well, the well is lined by sinking a steel casing, or liner, into the drilling mud (see Figure 1). The inside of the liner forms a central pipe, and leaves an annular gap between the outside of the liner and the surrounding rock. The inside and outside of the liner are initially filled with drilling mud, which is displaced by pumping a sequence of fluids down inside the lin...

Received: April 29, 2017 Revised: July 01, 2017 Accepted: August 30, 2017 Abstract: Introduction: Unloading phenomenon happens in the beginning of drilling and is able to change stress state around borehole. This change of stress state causes impact on rock structure and strength, thus affecting the evaluation of wellbore stability. Especially for determining initial mud pressure, unloading is ...

maybe viscosity in drilling fluid is the most important parameter because cutting removal from well are task of viscose fluid. if viscosity of fluid is less than particular value, cutting will settle down in well and drilling operation will be stopped. in this study, synthesis of alumina/polyacrylamide nanocomposite through solution polymerization method was performed. rheological behavior of m...

In directional drilling, the most important thing that leads to pulling out the drill string is end of mud motor working life. Considering the working conditions of down hole mud motors; increasing the mechanical properties of their stator’s elastomer is crucial. Some attempts were done to increase the motor performance through geometrical changes but lack of material improvement is significant...

Horizontal directional drilling (HDD) is widely used in soil and rock engineering. In a variety of conditions, it is necessary to estimate the torque required for performing the reaming operation. Nevertheless, there is not presently a convenient method to accomplish this task. In this paper, to overcome this difficulty based on the basic concepts of rock engineering systems (RES), a model for ...

Numerous studies have been presented, mainly in the petroleum literature, about permeability impairment of reservoir formations due to rock/drilling fluid interactions. For example, Glenn et a1;(1957) showed that mud particles can invade to an appreciable depth into the pores of a porous medium, form a "filter cake" in the pores, and cause a substantial reduction in the permeability of the inva...