A Successful Experience in Using Short Gauge PDC Bits for Drilling with Point-the-Bit Rotary Steerable Systems under Geological Conditions of Verkhnechonskoye Field

Abstract

The investigations, conducted by many companies, show that a long gauge PDC bits, which are used during operations with "point-the-bit" Rotary Steerable Systems (RSS), allows for mitigating the bit vibrations and improve steerability. But in this paper, we shall present the usage of the short gauge PDC bits when drilling with this type of RSS in a pay zone, which is characterized by hard streaks. More tight shaled-out interlayers were encountered in pay zone when developing a peripherical part of Verkhnechonskoye field. On the boundary of the rocks of different hardness a number of formation "pushes" (short intervals with a sharp change of the inclination) increased significantly. A continuous operation in the formation "push" intervals resulted in downhole equipment damages. When conducting kick-off operations in an open hole in multilateral wells with the use of "point-the-bit" RSS and the long gauge bits a quantity of failures reached 60 %. For that reason, it was necessary to kick off using a BHA with a downhole motor; but in this case additional runs are required. A hypothesis was made that the usage of short gauge PDC bits will help to promptly correct the wellbore trajectory when formation "push" occurs, as well as allow for drilling a few laterals over one run. Deviation from the standard design made it possible to reduce a number of runs when drilling multilateral wells, increase an average rate of penetration and significantly reduce frequency of Dogleg Severity exceedance events when passing through hard streaks.

Formulation and Study of an Environmentally Friendly Microemulsion-Based Drilling Fluid (O/W) with Pine Oil

“…The flow curve was then plotted from the obtained VG-meter data, and the rheological parameters were accessed. The apparent and plastic viscosities and the yield point were calculated using Equations ( 1)- (3). AV = θ 600 /2 (mPa.s),…”

“…The methyl band was observed at 1444 cm −1 and the geminal methyl, in pairs, at 1379 cm −1 and 1371 cm −1 . Bands at 1710 cm −1 and 1674 cm −1 are associated with C=C axial deformation, between 2965 cm −1 and 2924 cm −1 , referring to the C-H of saturated aliphatic carbon sp 3 , with the high-intensity characteristic of the terpene skeleton, and at 3375 cm −1 , to the stretch of O-H (Figure 10). Complete characterization of pine oil is not possible as the composition of the material is complex and variable.…”

“…Complete characterization of pine oil is not possible as the composition of the material is complex and variable. The infrared spectrum of the Tween 80, following the results of Ren et al [57], showed bands of angular deformation C-C and aliphatic C-H between 500 cm −1 and 1000 cm −1 , a signal referring to the deformation =C-H at 945 cm −1 , a signal of solid intensity characteristic of C-OH of primary alcohol at 1099 cm −1 , a 1460 cm −1 signal referring to me- The infrared spectrum of the Tween 80, following the results of Ren et al [57], showed bands of angular deformation C-C and aliphatic C-H between 500 cm −1 and 1000 cm −1 , a signal referring to the deformation =C-H at 945 cm −1 , a signal of solid intensity characteristic of C-OH of primary alcohol at 1099 cm −1 , a 1460 cm −1 signal referring to methyl, a C=C stretch at 1636 cm −1 , a weak signal at 1734 cm −1 for ester C=O, aliphatic CH sp 3 -s stretch at 2918 cm −1 (asymmetric) and 2859 cm −1 (symmetric), and an OH stretch at 3528 cm −1 (Figure 11). The infrared spectrum of the microemulsion, composed of glycerol, water, Tween 80, and pine oil, showed two signals referring to the C-OH stretch of a primary and secondary alcohol, at 1108 cm −1 and 1039 cm −1 , overlapping bands in the region from 1460 cm −1 to 1207 cm −1 referring to C-OH absorptions, CH2 deformation, methyl, and C=C stretching, a signal in 1649 cm −1 referring to the carbonyl (C=O) of ester, sp 3 -s stretching of aliphatic CH at 2928 cm −1 (asymmetric) and 2884 cm −1 (symmetric), and an OH stretch at 3340 cm −1 (Figure 12).…”

“…The success and the cost of rotary drilling depend substantially on factors such as the penetration rate of the drill bit into the formation; cleaning the face of the drill, as well as cleaning the bottom of the wellbore; and the support of the drilled wellbore. Drilling fluids directly affect all three factors mentioned [1][2][3][4][5]. It is often said that most problems in drilling operations are linked in some way to poor planning of the drilling fluids [6].…”