Experimental Investigation of the Effect of Shale Anisotropy Orientation on the Main Drilling Parameters Influencing Oriented Drilling Performance in Shale

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
A. N. Abugharara ◽  
Bashir Mohamed ◽  
C. Hurich ◽  
J. Molgaard ◽  
S. D. Butt
Keyword(s):  
Drilling Fluid ◽  
Polycrystalline Diamond ◽  
Bedding Plane ◽  
Depth Of Cut ◽  
Fine Aggregate ◽  
Drilling Rig ◽  
Drilling Performance ◽  
Bedding Planes ◽  
Weight On Bit ◽  
Shale Anisotropy

The influence of shale anisotropy and orientation on shale drilling performance was studied with an instrumented laboratory drilling rig with a 38.1-mm dual-cutter polycrystalline diamond compact (PDC) bit, operating at a nominally fixed rotational speed with a constant rate of flow of drilling fluid—water. However, the rate of rotation (rpm) was affected by the weight on bit (WOB), as was the torque (TRQ) produced. The WOB also affected the depth of cut (DOC). All these variables, WOB, rpm, TRQ, and DOC, were monitored dynamically, for example, rpm with a resolution of one-third of a revolution (samples at time intervals of 0.07 s.) The shale studied was from Newfoundland and was compared with similar tests on granite, also from a local site. Similar tests were also conducted on the concrete made with fine aggregate, used as “rock-like material” (RLM). The shale samples were embedded (laterally confined) in the concrete while drilled in directions perpendicular, parallel, and at 45 deg orientations to bedding planes. Cores were produced from all three materials in several directions for the determination of oriented physical properties derived from ultrasonic testing and oriented unconfined compressive strength (OUCS). In the case of shale, directions were set relative to the bedding. In this study, both primary (or compression) velocity Vp and shear ultrasonic velocity Vs were found to vary with orientation on the local shale samples cored parallel to bedding planes, while Vp and Vs varied, but only slightly, with orientation in tests on granite and RLM. The OUCS data for shale, published elsewhere, support the OUCS theory of this work. The OUCS is high perpendicular and parallel to shale bedding, and is low oblique to shale bedding. Correlations were found between the test parameters determined from the drilling tests on local shale. As expected, ROP, DOC, and TRQ increase with increasing WOB, while there are inverse relationships between ROP, DOC, and TRQ with rpm on the other hand. All these parameters vary with orientation to the bedding plane.

Study of the Influence of Shale Anisotropy Orientation on Directional Drilling Performance in Shale

2017 ◽  
Author(s):  
Abdelsalam N. Abugharara ◽  
Charles A. Hurich ◽  
John Molgaard ◽  
Stephen D. Butt
Keyword(s):  
Depth Of Cut ◽  
Directional Drilling ◽  
Laboratory Procedure ◽  
Drilling Rig ◽  
Drilling Performance ◽  
Mechanical Measurements ◽  
Different Types ◽  
Pdc Bit ◽  
Weight On Bit ◽  
Shale Anisotropy

The influence of shale anisotropy orientation on shale drilling performance has been studied using a new laboratory procedure. This procedure includes drilling and testing three sets of shale samples in different orientations from a single rock sample. Shale samples of different types were collected from outcrops located at Conception Bay South (CBS) in Newfoundland, Canada. For predrilling tests, oriented physical and mechanical measurements on each type of shale were conducted on the same rocks that will be drilled later. For drilling tests, three sets of tests were conducted. Each set was in a different orientation, corresponding to those in the physical and mechanical measurements. Each set was conducted under the same drilling parameters of pressure, flow rate (FR), and weight on bit (WOB) using a fully instrumented laboratory scale drilling rig. Two different types of drill bits were used, including a 35 mm dual cutter PDC bit and a 25.4 mm diamond coring bit. The drilling data was analyzed by constructing relationships between drilling rate of penetration (ROP) versus orientation (i.e. 0°, 45°, or 90°). The analysis also included relationships between WOB and bit cutter Depth of Cut (DOC), Revolution Per Minute (RPM), and Torque (TRQ). All the above relations were evaluated as a function of shale bedding orientation. This evaluation can assist in understanding the influence of shale anisotropy on oriented drilling. Details of the conducted tests and results are reported.

Hydraulic Percussion Drilling System with PDC Bit Increases ROP and Lowers Drilling Costs

2015 ◽  
Author(s):  
Scott W. Powell ◽  
Ertai Hu
Keyword(s):  
Distribution System ◽  
Drilling Fluid ◽  
New Technology ◽  
Polycrystalline Diamond ◽  
Depth Of Cut ◽  
Rapid Variation ◽  
Pdc Bit ◽  
Weight On Bit ◽  
Drilling System ◽  
Percussion Drilling

Abstract Drilling the Severnaya Truba Field in Aktobe, Kazahkstan, has proved to be a costly and time consuming challenge for operators trying to maximize profits. The formation is typically drilled with roller cone bits that take multiple runs to complete an interval. To increase effectiveness and drilling efficiency, a hydraulically powered percussion drilling system along with a fixed cutter PDC bit were added. In place of a conventional drilling system, a new energy distribution system was introduced that would induce axial oscillations and percussion impacts while applying the same weight and torsional energy to the bit. In combination with a drilling fluid powered percussion hammer (FPPH), a fit for application polycrystalline diamond compact (PDC) bit with depth of cut (DOC) control features was used to minimize the exposure of the cutting structure and prevent breakage. The system combines the torsional power of a conventional positive displacement motor with a high frequency axial pulse created with each rotation. The torque is transferred directly to the bit and 100% of the hydraulic flow is utilized by the bit nozzles to maintain hole cleaning and keep PDC cutters cool. The mechanical lifting and falling action creates a rapid variation in weight on bit (WOB), allowing the bit's depth of cut to fluctuate while overcoming different stresses. These variations, along with the percussion pulse created with each stroke, lead to increased rates of penetration. This system has been used throughout the world on a variety of formations, using both PDC and roller cone insert bits. This paper will focus on an 8½ in interval drilling operation in the Severnaya Truva field, located 60 km from Zhanazhol field in Kazakhstan. The formations consisted of soft to medium siltstone, red/grey clays, sandstone, hard cemented dolomite, limestone, and very dense clay stone. This new technology proved to increase both ROP and interval drilled, saving seven days of drilling compared to offset wells.

Drilling Cutting Analysis to Assist Drilling Performance Evaluation in Hard Rock Hole Widening Operation

2020 ◽  
Author(s):  
Daiyan Ahmed ◽  
Yingjian Xiao ◽  
Jeronimo de Moura ◽  
Stephen D. Butt
Keyword(s):  
Performance Enhancement ◽  
Ore Deposits ◽  
Drilling Process ◽  
Rotary Drilling ◽  
Pilot Hole ◽  
Drilling Rig ◽  
Drilling Performance ◽  
Drilling Parameters ◽  
Weight On Bit ◽  
Drilling Operations

Abstract Optimum production from vein-type deposits requires the Narrow Vein Mining (NVM) process where excavation is accomplished by drilling larger diameter holes. To drill into the veins to successfully extract the ore deposits, a conventional rotary drilling rig is mounted on the ground. These operations are generally conducted by drilling a pilot hole in a narrow vein followed by a hole widening operation. Initially, a pilot hole is drilled for exploration purposes, to guide the larger diameter hole and to control the trajectory, and the next step in the excavation is progressed by hole widening operation. Drilling cutting properties, such as particle size distribution, volume, and shape may expose a significant drilling problem or may provide justification for performance enhancement decisions. In this study, a laboratory hole widening drilling process performance was evaluated by drilling cutting analysis. Drill-off Tests (DOT) were conducted in the Drilling Technology Laboratory (DTL) by dint of a Small Drilling Simulator (SDS) to generate the drilling parameters and to collect the cuttings. Different drilling operations were assessed based on Rate of Penetration (ROP), Weight on Bit (WOB), Rotation per Minute (RPM), Mechanical Specific Energy (MSE) and Drilling Efficiency (DE). A conducive schedule for achieving the objectives was developed, in addition to cuttings for further interpretation. A comprehensive study for the hole widening operation was conducted by involving intensive drilling cutting analysis, drilling parameters, and drilling performance leading to recommendations for full-scale drilling operations.

Experimentally-Tuned Mathematical Model for Drillstring Vibrations

2007 ◽  
Author(s):  
Y. A. Khulief ◽  
F. A. Al-Sulaiman
Keyword(s):  
Dynamic Models ◽  
Drilling Fluid ◽  
Experimental Studies ◽  
Published Data ◽  
Test Rig ◽  
Stick Slip ◽  
Multibody Model ◽  
Drilling Performance ◽  
Weight On Bit ◽  
Functional Operation

Field experience manifests that drillstring vibration is one of the major causes for a deteriorated drilling performance. It is crucial to understand the complex vibrational mechanisms experienced by a drilling system in order to better control its functional operation and improve its performance. Experimental studies of drillstring dynamics are essential to complement the theoretical studies, and to alleviate the complexity of such dynamic models. This paper presents an experimental investigation using a specially designed drilling test rig. The test rig can simulate the drillstring vibrational response due to various excitation mechanisms, which include stick-slip, well-borehole contact, and drilling fluid interaction. The test rig is driven by a variable speed motor which allows for testing different drilling speeds, while a magnetic tension brake is used to simulated stick-slip. In addition, a shaker is employed to excite the drillstring axially in order to simulate the weight-on-bit (WOB). The drillstring is instrumented for vibration measurements. The experimentally identified parameters are used to refine the finite element multibody model of the drillstring, which was derived earlier by the investigators [1]. Comparisons with published data demonstrate the reliability of the developed scheme for prediction of drillstring vibrations.

Study of the Relationship Between Oriented Downhole Dynamic Weight on Bit and Drilling Parameters in Coring Isotropic Natural and Synthetic Rocks

2019 ◽  
Author(s):  
Abdelsalam N. Abugharara ◽  
John Molgaard ◽  
Charles A. Hurich ◽  
Stephen D. Butt
Keyword(s):  
Water Flow Rate ◽  
Sampling Rate ◽  
Depth Of Cut ◽  
Rotary Drilling ◽  
Drilling Rig ◽  
Isotropic Rock ◽  
Dynamic Weight ◽  
Drilling Parameters ◽  
Weight On Bit ◽  
Rock Characterization

Abstract Coring natural rocks (granite) and synthetic rocks (rock like material, RLM) using diamond impregnated coring bit was performed by A rigid coring system. RLM and granite were previously tested to be isotropic rocks by the author [1, 2, 3, 4] A baseline procedure was developed for isotropic rock characterization [2] and this work is to contribute to the developed baseline procedure by considering downhole dynamic weight on bit (DDWOB). The drilling parameters involved in the analysis included rate of penetration (ROP) depth of cut (DOC), rpm, and torque. All parameters were studied as a function of DDWOB at 300 and 600 input rpm. A fully instrumented laboratory scale rotary drilling rig was used with 5 liter/minute water flow rate. Samples were first cored in 47.6 mm diameter in the desired orientations. Samples of granite were cored in two perpendicular directions (vertical and horizontal) and samples of RLM were cored in three directions including vertical, oblique, and horizontal. The coring experiments were performed using 25.4 mm diamond impregnated coring bit. At each input rpm and at each applied static weight, multiple coring runs were repeated and then averaged; therefore, each point of the displayed data was averaged of at least three repeated experiments at the same inputs. DDWOB was recorded by a load cell fixed beneath the sample holder and connected to a Data Acquisition System that records at 1000 HZ sampling rate. Several sensors were used to record the required data, including operational rotary speed, advancement of drill bit for ROP calculation, and motor current for torque measurement. Results showed similar trends in different orientations at the same inputs demonstrating RLM and granite isotropy. The results also showed the influence of DDWOB on ROP, DOC, rpm, and torque (TRQ) expanding the baseline procedure through considering DDWOB for isotropic rock characterization.

Mathematical Model of the Diamond-Bit Drilling Process and Its Practical Application

1982 ◽  
Vol 22 (06) ◽  
pp. 911-922 ◽  
Author(s):  
Malgorzata B. Ziaja ◽  
Stefan Miska
Keyword(s):  
Penetration Rate ◽  
Drilling Fluid ◽  
Active Surface ◽  
Rock Properties ◽  
Depth Of Cut ◽  
Drilling Process ◽  
Diamond Cutting ◽  
Rate Of Penetration ◽  
Drilling Performance ◽  
Diamond Bit

Abstract With several limiting assumptions, a mathematical model of the diamond-bit drilling, process has been developed. The model represented by an instantaneous rate-of-penetration equation takes into account the reduction in penetration rate during drilling resulting from bit wear. The model has been tested both under laboratory and under field conditions. The comparison of the theoretical and experimental results has shown reasonable agreement. A method for estimating rock properties also has been established. Using this method, we can find the so-called index of rock strength and the index of rock abrasiveness. Introduction Several published studies concerned with diamond-bit drilling report on rock properties and drillability. drilling fluid additives, diamond wear, and drilling performance theories. Among the factors, that affect diamond-bit drilling performance, the type of formation to be drilled is of utmost importance since it significantly affects the type of bit, the drilling practices. and subsequently the rate of penetration and the drilling cost. The nature of the formation is also one of the main factors in planning deep wells, fracture jobs, mud and cement technologies, etc. For rock properties evaluation as well as for selection of proper drilling practices, several descriptions of the diamond-bit drilling process have been developed. The relevant literature is extensive and is not reviewed in this paper. The objective of this paper is to describe the diamondbit drilling model for surface-set diamond core bits and its application to determining the index of formation strength and the index of formation abrasiveness. The main difference between our model and the models known in literature is that we consider the effect of friction between the diamond cutting surfaces and the rock. A decrease in penetration rate is observed if the drilling parameters, are constant and if the formation is macroscopohomogeneous. Drilling Model The drilling model for a surface-set diamond core bit is subjected to the following limiting assumptions.Rock behavior during cutting with a single diamond may be approximated by a rigid Coulomb plastic material.The active surface of the bit is flat, and diamonds are spherical with diameter. d.The cross-sectional area of the chip formed by a single diamond is equal to the diamond cutting surface and can be established by geometry.During drilling, the neighboring diamonds work together to make a uniform depth of cut (Fig. 1).A number of diamonds forming one equivalent blade have to provide it uniform depth of cut from the inner to the outer diameter of the diamond core bit. so the bit is modeled to be a combination of several equivalent blades (Fig. 2).The diamond distribution technique provides uniform radial coverage that results in equally loaded cutting diamonds.Individual cutting diamonds perform some work that results from the friction between the rock and the diamond.Bit wear is assumed to be gradual while drilling is in progress. Under the preceding assumptions we may state that the drilling rate of the surface-set diamond core bit is a function only of weight on bit (WOB), rotary speed, average density of the diamonds on the bit's active surface, diamond size, core-bit diameters, rock properties, and degree of diamond dullness. The effects of flow rate, differential pressure, hydraulic lift, drilling fluid properties. and drillstring dynamics are ignored. According to Peterson, the penetration rate of the diamond bit, after some modifications, can be described by the following simplified equation. (1) This equation does not include the effect of diamond wear and hence pertains to unworn bits or to when bit dullness is negligible. SPEJ P. 911^

Baseline Development of Rock Anisotropy Investigation Utilizing Empirical Relationships Between Oriented Physical and Mechanical Measurements and Drilling Performance

2016 ◽  
Author(s):  
Abdelsalam N. Abugharara ◽  
Abourawi M. Alwaar ◽  
Stephen D. Butt ◽  
Charles A. Hurich
Keyword(s):  
Elastic Moduli ◽  
Physical And Mechanical Properties ◽  
Point Load ◽  
Depth Of Cut ◽  
Anisotropic Rock ◽  
Flow Rates ◽  
Drilling Rig ◽  
Drilling Performance ◽  
Mechanical Measurements ◽  
Rock Anisotropy

This paper describes a baseline investigation to confirm the isotropy of rocks material through physical and mechanical measurements followed by oriented drilling. This baseline is intended to evaluate drilling experiments in anisotropic rock materials to determine the significance of the anisotropy on drilling performance. The conducted tests include oriented measurements of compressional and shear wave velocities (Vp and Vs, respectively), density, Elastic Moduli, Point Load Strength Index (PLI), Indirect Tensile (IT) strength, and Unconfined Compressive Strength (UCS). The oriented laboratory drilling experiments were conducted under various pump flow rates and several weights on bit (WOB). In this work, an isotropic rock like material (RLM) was developed using Portland cement and fine-grained aggregate. The tested RLM specimens were of medium strength of ∼50 MPa. The RLM samples were cored in different orientations and then, tested and drilled according to these orientations. (e.g. 0°, 45° and 90°, representing horizontal, diagonal and vertical directions, respectively). Two main sets of lab tests were performed including pre-drilling and drilling tests. For the pre-drilling lab experiments, two main sets of tests were conducted to determine the physical and mechanical properties of samples (as outlined above) including PLI, IT, UCS, Vp, Vs, density and corresponding isotropic Dynamic Elastic Moduli. For the drilling tests, a vertical lab scale drilling rig was used with a 35 mm dual-cutter Polycrystalline Diamond Compact “PDC” bit. The drilling parameters involved were flow rates, nominal rotary speed of 300 rpm, and various WOB under atmospheric pressure. The relationships between the drilling data were analyzed including drilling rate of penetration (ROP), depth of cut (DOC), and corresponding effective WOB. The results of all mechanical, physical and drilling measurements and tests show consistent values indicating the isotropy of the tested rock material. This consistency verifies that the drilling tests are free of bias associated with drilling orientation.

Study of the Influence of Controlled Axial Oscillations of pVARD on Generating Downhole Dynamic WOB and Improving Coring and Drilling Performance in Shale

2019 ◽  
Author(s):  
Abdelsalam N. Abugharara ◽  
John Molgaard ◽  
Charles A. Hurich ◽  
Stephen D. Butt
Keyword(s):  
Sampling Rate ◽  
Polycrystalline Diamond ◽  
Rotary Drilling ◽  
Labview Software ◽  
Drilling Performance ◽  
Drilling Parameters ◽  
Wide Range ◽  
Pdc Bit ◽  
Weight On Bit ◽  
Polycrystalline Diamond Compact

Abstract This work concentrates on the investigation of enhancing drilling performance through increasing drilling rate of penetration (ROP) by using a passive vibration assisted rotary drilling (pVARD) tool. It also involves analysis of how ROP was significantly increased when drilling using pVARD compared to drilling using conventional system “rigid” using coring and drilling in shale rocks. The apparatus used was a fully instrument laboratory scale rig and the bits were dual-cutter polycrystalline diamond compact (PDC) bit for drilling and diamond impregnated coring bit for coring. The flow rate was constant of (7 litter / min) using clean water at atmospheric pressure. In addition, for accuracy data recording, a data acquisition system (DAQ-Sys) using a LabVIEW software was utilized to record data at 1000HZ sampling rate. The output drilling parameters involved in the analysis included operational rpm, torque (TRQ), and ROP. All the output-drilling parameters were analyzed with relation to downhole dynamic weight on bit (DDWOB). The result of this work explained how pVARD can increase the DDWOB and improve ROP. The result also demonstrated generating a balanced and concentric increase in DDWOB and minimizing the wide-range fluctuation of DDWOB generated in rigid drilling, particularly at high DDWOB.

Analysis of Surface Set Diamond Bit Performance

1969 ◽  
Vol 9 (03) ◽  
pp. 301-310 ◽  
Author(s):  
D.S. Rowley ◽  
F.C. Appl
Keyword(s):  
Drilling Fluid ◽  
Complete Analysis ◽  
Depth Of Cut ◽  
Rigid Plastic ◽  
Rock Formation ◽  
Drilling Performance ◽  
Cutting Surface ◽  
The Individual ◽  
Drilling Conditions ◽  
Diamond Bit

Abstract With, the assumption of perfect cleaning, a theory of the drilling performance of surface set diamond bits has been developed. The analysis is based on the previously developed theory of the cutting action of a single diamond, in which it was assumed that rock behavior during cutting may be approximated by that of a rigid-plastic, Coulomb material. With specified drilling conditions and rock formation, expressions for bit torque and bit weight are obtained in terms of bit penetration rate. Expressions also are obtained for the depths of cut of the diamonds. Note that depth of cut and diamond cutting force vary considerably over the cutting surface of the bit. Theoretical results are compared with experimental results for full hole bits and core bits. The agreement is reasonable. Introduction A theoretical analysis of single diamond cutting action on rock has been presented. Equations were established for the stress distribution on the cutting surface of the diamond, for the normal and the tangential cutting forces, and for the chip volume removed by the diamond. These relations were obtained by assuming that the principal, mode of material removal is by "ploughing", and that the rock formation may be approximated by a rigid-plastic, Coulomb material. It is pertinent to consider the drilling performance of a surface set diamond bit, since the over-all performance is determined by the total effect of the individual diamonds on the cutting surface of the bit. A complete analysis of surface set diamond bit performance should take into account the interaction performance should take into account the interaction of the drilling fluid with the mechanics of the cutting action. All material loosened by the diamonds must be carried away by the drilling fluid as it flows between the cutting face of the bit and the rock being cut. The geometry of the clearance between bit and rock is dependent on the diamond catting action as well as the bit geometry. Still there are many factors related to chip generation and removal. that are not understood, and hence, a complete analysis of bit performance including bit hydraulics effects has not been attempted. The present study relates primarily to the mechanics of cutting. It will be assumed that all of the material removed by the diamonds is immediately flushed away by the drilling fluid. The performance of a diamond bit will be determined for conditions of "perfect cleaning". Theoretical results for penetration rate will, therefore, correspond to the upper limit insofar as cleaning is concerned. Using the previous theory of cutting action, one important step remains in order to determine diamond bit performance. The depth of cut of the diamonds must be determined in terms of bit geometry and drilling rate. Most bits have a relatively large number of diamonds spaced rather closely, together. Various spacing patterns are used. However, irregularities in diamond shape and variation due to manufacturing procedures result in deviations that are as large or procedures result in deviations that are as large or larger than the average depth of cut of the individual diamonds. On a new bit it is probable that there are some diamonds that do not cut at all. It seems impractical to attempt to determine the depth of cut of each individual diamond. Statistical treatment of the depth of cut is perhaps the most desirable. Since there is a large number of cutting points, it has been assumed that the performance of the bit as a whole does not depend significantly on the exact nature of the variation in depth of cut and spacing at each radius. We assumed that at any given radius on the bit cutting surface, the diamonds are either randomly spaced or uniformly spaced and that the diamonds along the circumference at any given radius share the work equally. Also, we assume that the drilling conditions and the rock formation remain constant and that steady-state conditions prevail. SPEJ P. 501

A Dynamic Model for Rotary Rock Drilling

1982 ◽  
Vol 104 (2) ◽  
pp. 108-120 ◽  
Author(s):  
I. E. Eronini ◽  
W. H. Somerton ◽  
D. M. Auslander
Keyword(s):  
Drill Pipe ◽  
Tooth Wear ◽  
Drill String ◽  
Rock Drilling ◽  
Large Power ◽  
Drilling Rig ◽  
Drilling Performance ◽  
Weight On Bit ◽  
Rotary Speed ◽  
Mud Pressure

A rock drilling model is developed as a set of ordinary differential equations describing discrete segments of the drilling rig, including the bit and the rock. The end segment consists of a description of the bit as a “nonideal” transformer and a characterization of the rock behavior. The effects on rock drilling of bottom hole cleaning, drill string-borehole interaction, and tooth wear are represented in the model. Simulated drilling under various conditions, using this model, gave results which are similar to those found in field and laboratory drilling performance data. In particular, the model predicts the expected relationships between drilling rate and the quantities, weight on bit, differential mud pressure, and rotary speed. The results also suggest that the damping of the longitudinal vibrations of the drill string could be predominantly hydrodynamic as opposed to viscous. Pulsations in the mud flow are found to introduce “percussive” effects in the bit forces which seem to improve the penetration rate. However, it is known from field observations that drill pipe movements, if strong enough, may induce mud pressure surges which can cause borehole and circulation problems. Bit forces and torques are shown to be substantially coupled and the influence of certain rock parameters on variables which are measurable either at the bit or on the surface support the expectation that these signals can furnish useful data on the formation being drilled. Other results, though preliminary, show that the effects of the lateral deflections of the drill string may be large for the axial bit forces and significant for the torsional vibrations. For the latter, the unsteady nature of the rotation above the bit increases and the resistance to rotation due to rubbing contact between the drill string and the wellbore accounts for very large power losses between the surface and the bit.

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