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 ...

Drill cuttings are considered representative of the lithology being drilled in a wellbore. However, the fragments that are two to three times larger and/or having odd shapes compared to the regular cuttings are commonly understood as cavings from the wall of the borehole and they are seldom of any help in compilation of a lithology. In fact, cutting description manual recommends ignoring cuttin...

Geoscientists from the Coso Operating Company, EGI-Utah, GeoMechanics International, and the U.S. Geological Survey are cooperating in a multi-year study to develop an Enhanced Geothermal System (EGS) in the Coso Geothermal Field. Key to the creation of an EGS is an understanding of the relationship among natural fracture distribution, fluid flow, and the ambient tectonic stresses that exist wi...

The buckling behavior of rod strings in wellbore is one of the key issues in petroleum engineering. The slender rod strings in vertical wellbore were selected as research objects. Based on the energy method, the critical load formulas of sinusoidal and helical buckling were derived for the string with the bottom of the wellbore pressure. According to the sinusoidal and helical buckling’s geomet...

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...

Two-phase flow (flow of water in both liquid and gas phase, containing a non-condensable such as CO 2 ) the wellbore is one most important processes production performance scaling evaluations high temperature geothermal wells. This paper first describes discharge tests Yangbajing field, Tibet. Next, simple model for governing two-phase presence constructed robust calculation method presented. T...

A dramatic decrease in the ratio of chloride to boron was observed in the liquid discharge of a well proposed for EGS development in the Coso geothermal field. The decrease appears to be related to the transformation of some feed zones in the well from liquid-dominated to vapor-dominated. High concentrations of boron are transported to the wellbore in the steam, where it fractionates to the liq...

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...

A coupled reservoir/wellbore simulator is essential for solving relevant flow phenomena with dynamic interactions between reservoir and wellbore in two-phase systems. or alone fails to solve these transient phenomena. This paper summarises a critical review of the simulation. First, wide application drift-flux (DF) models simulate gas–liquid model coupling was discussed. Then, mechanisms system...