Critical Conditions for Effective Sand-Sized Solids Transport in Horizontal and High-Angle Wells

Abstract

fax 01-972-952-9435. AbstractEffective removal of small sand-sized solids is critical for successful drilling and completion operations in sand reservoirs. Recent experience in extended reach drilling also indicates that inefficient transport of smaller cuttings is a main factor for excessive drag and torque. This study was undertaken to determine two critical conditions for efficient transport of small solids. The two conditions are represented by the Critical Re-Suspension Velocity (CRV), the minimum fluid velocity necessary to initiate solids bed erosion, and the Critical Deposition Velocity (CDV), the minimum fluid velocity required to prevent bed formation.Experiments were conducted in a field-scale flow loop (8×4.5 in., 100-ft long) to determine CRV and CDV, for 0.45 mm and 1.4 mm sands in different fluids over a range of bed heights and hole inclinations. The results show that, depending on sand size and fluid properties, CDV is approximately two to three times larger than CRV. Water is more effective than low concentration polymer solutions for bed erosion. However, polymer solutions are more helpful than water in preventing bed formation. This indicates the need for different drilling fluids for cleanout and drilling operations.A mechanistic model was developed to predict CRV for a solids bed. Both experimental and theoretical results indicate the importance of inter-particle forces that are incorporated into the model. The model accounts for drill pipe eccentricity in any direction in an annulus, which is consistent with experimental observations. The model predictions are in good agreement with experimental results. Existing CDV correlations developed for larger cuttings were verified by experimental data for sands. The differences are around 25%. Results in this study will be useful not only in drilling and completion through sand reservoirs, but also in extended reach drilling and sand control.

Experimental investigation of hole cleaning in directional drilling by using nano-enhanced water-based drilling fluids

“…However, if the viscosity of the drilling mud and rotational speed are high, cuttings that are smaller in size can be transported efficiently to the surface (Sanchez et al, 1999). Duan et al (2009) suggested that various fluids are required for different purposes. Water is usually required for cleanout and polymer solutions are required for drilling operations.…”

Simulation and Experimental Study on Fishing Performance of Vacuum Suction Wellbore Cleaning Tool

“…However, this method has low cleaning efficiency and easily causes sticking when applied to horizontal wells [9,10]. erefore, for the problem of poor rock carrying effect, Bashir [7], Ozbayoglu et al [11], Duane et al [12], Han et al [13], and Tie et al [14] used a special downhole device to generate eddies to improve the fluid's ability to transport particles. However, when the sediment particles at the bottom of the well are large, they cannot be carried out of the well head.…”

A study on non-spherical cuttings transport in CBM well drilling by coupled CFD-DEM

“…Because of the specificity of the coal stratum and the structural complexity of the coal bed methane (CBM) wells, non-spherical cuttings in a larger size are more often produced during the drilling process. These large drill cuttings will not only bring impact failures to both strings and the well-wall, but also generate local blockages which may cause serious downhole problems like the jamming of the drilling tools (Akbarian et al, 2018;Akhshik & Rajabi, 2018;Duan, Miska, Yu, Takach, & Ahmed, 2007). Moreover, in the next stage of CBM production, failing to discharge the cuttings in a timely way is likely to cut back gas production.…”

“…Sanchez, Azar, Bassal, and Martins (1999) CONTACT Bing Shao sealkite@163.com; Yifei Yan upcshaobing@163.com took the rotation of the drill pipe into account and studied the well-hole cleaning in the process of directional well drilling. Duan et al (2007) did simulation work on cuttings transport in horizontal and inclined wells with a big angle, in which critical conditions including the CRV (critical re-suspension velocity), the CFV (critical fluid velocity), and the CDV (critical deposition velocity) are discussed in detail. Song, Guan, and Chen (2009) developed the analytic models of CFV for different moving patterns of cuttings.…”