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 ...

The fate of discharged drilling muds is an ongoing issue for offshore petroleum operators, regulators, the fishing industry and environmentalists. The problem is compounded by difficulties in measuring transient mud concentrations and in relating experience gained at one location to locations with different oceanographic characteristics. We use the benthic boundary layer transport model (bblt) ...

The growing energy demand in the world, as well current geopolitical situation, require countries to additional investments exploration and production of hydrocarbons from their own sources. This means that companies must develop new fields which have remained undeveloped until now mostly because extremely harsh environment where they are located (deep sea, high temperature, pressure, heavy oil...

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...

The first stage to have access to a reservoir is the drilling operation. The proper development of this operation plays a major role in increasing productivity. It must be pointed out that the drilling fluid (mud) is pivotal in achieving this objective. Among these fluids, water-based fluids are the most common ones, which have been utilized to drill approximately 80% of all wells and are m...

During drilling, almost 70% of wellbore instability issues result from the encountering shale formations. Various additives such as salts, silicates, and polymers are used in water-based mud to enhance its shale-inhibition capability; however, have certain limitations. Lately, ionic liquids deep eutectic solvents (DES) been by various research groups inhibitors drilling fluid due their biodegra...

The onset of the Paleocene–Eocene thermal maximum (PETM) and associated carbon isotope excursion (CIE; approx. 56 Mya) was geologically abrupt, but it is debated whether it took thousands of years or was effectively instantaneous. Wright and Schaller (2013) published a significant new record of the onset of the CIE, and claimed that it could be resolved across 13 annual layers in a drill core t...

The purpose of this study is to improve the cementing quality of shale gas well by mud cake solidification, as well as to provide the better annular isolation for its hydraulic fracturing development. Based on the self-established experimental method and API RP 10, the effects of mud cake solidifiers on the shear strength at cement-interlayer interface (SSCFI) were evaluated. After curing for 3...