Wellbore stability are influenced by many complex factors, and there is no commonly used prediction method on wellbore stability until now. Use of an efficient decision making technique which can take into account several criteria in such conditions is necessary. Referring to traditional wellbore stability analyzing methods, the fuzzy comprehensive evaluation method of predicting wellbore stabi...

The past decade has seen increased focus on nanoparticle (NP) based drilling fluid to promote wellbore stability in shales. With the plugging of NP into shale pores, the fluid pressure transmission can be retarded and wellbore stability can be improved. For better understanding of the interaction between shale and NP based drilling fluid based on previous pressure transmission tests (PTTs) on A...

optimization of drilling fluid parameters such as mud weight, salt concentration, and temperature is essential to alleviate instability problems during drilling through shale sections. the selection of suitable mud parameters can benefit from analyses that consider significant instability processes involved in shale-drilling–fluid interactions. this paper describes the development of analytical...

Determination of the borehole and fracture initiation positions is the main aim of a borehole stability analysis. A wellbore trajectory optimization with the help of the mud pressure may be unreasonable since the mud pressure can only reflect the degree of difficulty for the initial damage to occur at the wellbore rather than the extent of the wellbore damage. In this work, we investigate...

fluid invasion from water-based drilling mud (wbdm) into the shale formations causes swelling,high pressure zone near the wellbore wall, and eventually wellbore instability problems duringdrilling operations. for the stability of the wellbore, physical plugging of nanoscale pore throats couldbe considered as a logical approach toward avoiding the fluid invasion into the shale formation. thispap...

Fluid invasion from water-based drilling mud (WBDM) into the shale formations causes swelling, high pressure zone near the wellbore wall, and eventually wellbore instability problems during drilling operations. For the stability of the wellbore, physical plugging of nanoscale pore throats could be considered as a logical approach toward avoiding the fluid invasion into the shale formation. This...

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 ...