Intermittent operation can improve the coefficient of performance (COP) of a ground source heat pump (GSHP) system. In this paper, an analytical solution to analyze the geo-temperature restoration performance under intermittent operation of borehole heat exchanger (BHE) fields is established. For this purpose, the moving finite line source model is combined with the g-function and the superposi...

We describe a new method to simulate 3D borehole resistivity measurements at zero frequency (DC). The method combines the use of a Fourier series expansion in a non-orthogonal system of coordinates with an existing 2D goal-oriented higher-order self-adaptive hpfinite element algorithm. The new method is suitable for simulating measurements acquired with borehole logging instruments in deviated ...

In this paper, an analytical method based on the multiple signal classification (MUSIC) algorithm is applied to three-dimensional (3-D) estimation of target positions using a directional borehole radar. A cylindrical conformal array on a conducting cylinder in a borehole was used for experimental measurements estimating the position of targets. It is also shown that the algorithm provides much ...

This paper presents a theoretical study of the discharge characteristics of slim holes compared to production wells. Assuming that (1) the boreholes feed from an all-liquid zone, and (2) the feedzone pressure and temperature are independent of borehole diameter, calculations have been carried out for a variety of borehole diameters. The wellhead pressurelflowrate relationships for the various b...

A combination of borehole Stoneley waves from full waveform acoustic logs and direct shear wave logs was used to estimate formation permeability and shear wave velocity. Data sets used here were collected by ARea's array full waveform acoustic logging tool and shear wave logging tool. The Pand S-wave velocities of the formation are determined by threshold detection with cross-correlation correc...

The goal of this work was to study the diversity of microorganisms inhabiting a deep subsurface aquifer system in order to understand their functional roles and interspecies relations formed in the course of buried organic matter degradation. A microbial community of a deep subsurface thermal aquifer in the Tomsk Region, Western Siberia was monitored over the course of 5 years via a 2.7 km deep...

Fluid pressure inside a borehole produces hydraulic fracture and damage zones in the vicinity of the borehole. These fractures result from stress concentrations around the borehole. The results of numerical simulation of a borehole subjected to fluid pressure using a micromechanical damage model [2] are presented in this paper. It is observed that tensional concentrated stresses are generated a...

36 JPT • NOVEMBER 2014 To estimate reserves, optimize well recovery, and place future development wells more accurately, operators require increasingly detailed understanding of complex oil and gas reservoirs. Highresolution geological data from the borehole—core samples and wireline microresistivity images—are essential to fully characterize reservoir architecture, guide and constrain reservoi...

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 ...