Drilling-Fluid Rheology Under Deepwater Drilling Conditions

Abstract The design features and the need to use a water-based solution make the task of ensuring trouble-free drilling of vertical wells non-trivial. This work is an example of an interdisciplinary approach to the analysis of the mechanisms of instability of the wellbore. Instability can be caused by a complex of reasons, in this case, standard geomechanical calculations are not enough to solve the problem. Engineering calculations and laboratory chemical studies are integrated into the process of geomechanical modeling. The recommendations developed in all three areas are interdependent and inseparable from each other. To achieve good results, it is necessary to comply with a set of measures at the same time. The key tasks of the project were: determination of drilling density, tripping the pipe conditions, parameters of the drilling fluid rheology, selection of a system for the best inhibition of clay swelling.

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Scaling Formulae for the Wellbore Hydraulics Similitude with Drill Pipe Rotation and Eccentricity

10.2118/204637-ms ◽

2021 ◽

Author(s):

Thad Nosar ◽

Pooya Khodaparast ◽

Wei Zhang ◽

Amin Mehrabian

Keyword(s):

Power Law ◽

Flow Rate ◽

Annular Flow ◽

Rotation Speed ◽

Drilling Fluid ◽

Drill Pipe ◽

Flow Loop ◽

Annular Flows ◽

Fluid Rheology ◽

Pipe Rotation

Abstract Equivalent circulation density of the fluid circulation system in drilling rigs is determined by the frictional pressure losses in the wellbore annulus. Flow loop experiments are commonly used to simulate the annular wellbore hydraulics in the laboratory. However, proper scaling of the experiment design parameters including the drill pipe rotation and eccentricity has been a weak link in the literature. Our study uses the similarity laws and dimensional analysis to obtain a complete set of scaling formulae that would relate the pressure loss gradients of annular flows at the laboratory and wellbore scales while considering the effects of inner pipe rotation and eccentricity. Dimensional analysis is conducted for commonly encountered types of drilling fluid rheology, namely, Newtonian, power-law, and yield power-law. Appropriate dimensionless groups of the involved variables are developed to characterize fluid flow in an eccentric annulus with a rotating inner pipe. Characteristic shear strain rate at the pipe walls is obtained from the characteristic velocity and length scale of the considered annular flow. The relation between lab-scale and wellbore scale variables are obtained by imposing the geometric, kinematic, and dynamic similarities between the laboratory flow loop and wellbore annular flows. The outcomes of the considered scaling scheme is expressed in terms of closed-form formulae that would determine the flow rate and inner pipe rotation speed of the laboratory experiments in terms of the wellbore flow rate and drill pipe rotation speed, as well as other parameters of the problem, in such a way that the resulting Fanning friction factors of the laboratory and wellbore-scale annular flows become identical. Findings suggest that the appropriate value for lab flow rate and pipe rotation speed are linearly related to those of the field condition for all fluid types. The length ratio, density ratio, consistency index ratio, and power index determine the proportionality constant. Attaining complete similarity between the similitude and wellbore-scale annular flow may require the fluid rheology of the lab experiments to be different from the drilling fluid. The expressions of lab flow rate and rotational speed for the yield power-law fluid are identical to those of the power-law fluid case, provided that the yield stress of the lab fluid is constrained to a proper value.

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Determination of drilling fluid rheology under downhole conditions by using real-time distributed pressure data

Journal of Natural Gas Science and Engineering ◽

10.1016/j.jngse.2015.04.004 ◽

2015 ◽

Vol 24 ◽

pp. 400-411 ◽

Cited By ~ 20

Author(s):

Ali Karimi Vajargah ◽

Eric van Oort

Keyword(s):

Real Time ◽

Drilling Fluid ◽

Pressure Data ◽

Fluid Rheology ◽

Distributed Pressure

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Application of R/S Rheometer in Low Temperature Drilling Fluid Rheology Determination

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.490-495.3114 ◽

2012 ◽

Vol 490-495 ◽

pp. 3114-3118

Author(s):

Xiao Ling Jiang ◽

Zong Ming Lei ◽

Kai Wei

Keyword(s):

Shear Stress ◽

Shear Rate ◽

Low Temperature ◽

High Speed ◽

Drilling Fluid ◽

Drilling Fluids ◽

Rheological Parameter ◽

Fluid Temperature ◽

Fluid Rheology ◽

Rotary Viscometer

With six-speed rotary viscometer measuring the rheology of drilling fluid at low temperature, during the high-speed process, the drilling fluid temperature is not constant at low temperature, which leads to the inaccuracy in rheological measurement. When R/S rheometer is used cooperating with constant low-temperature box , the temperature remains stable during the process of determining the drilling fluid rheology under low temperature. The R/S rheometer and the six-speed rotational viscometer are both coaxial rotational viscometers, but they work in different ways and the two cylindrical clearance between them are different.How to make two viscometer determination result can maintain consistent?The experimental results show that, The use of R/S rheometer, with the shear rate for 900s-1 shear stress values instead of six speed rotary viscometer shear rate for 1022s-1 shear stress values.Then use two-point formula to calculate rheological parameters.The R/S rheometer rheological parameter variation with temperature has a good linear relationship,Can better reflect the rheological properties of drilling fluids with low temperature changerule

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Experimental Evaluation of Separation Methods for a Riser Dilution Approach to Dual Density Drilling

Volume 7: Offshore Geotechnics; Petroleum Technology ◽

10.1115/omae2009-80113 ◽

2009 ◽

Author(s):

John Shelton ◽

John Rogers Smith ◽

Anuj Gupta

Keyword(s):

Emulsion Stability ◽

Drilling Fluid ◽

Feed Stream ◽

Separation System ◽

Qualitative Comparison ◽

Deepwater Drilling ◽

Drilling System ◽

The Stability ◽

Dual Gradient ◽

Laboratory Centrifuge

A dual gradient, deepwater drilling system based on dilution of riser mud requires economically separating the riser mud into a low density dilution fluid and a higher density drilling fluid. This study investigated the practicality of accomplishing this separation using hydrocyclones and centrifuges and examined the possible benefits and efficiency of each. The separation experiments were conducted using a laboratory centrifuge and 2 inch hydrocyclones. The laboratory centrifuge was able to separate the riser mud into near ideal densities for dilution and drilling fluid. However, the dense slurry retained in the centrifuge had lower emulsion stability than the feed stream. The hydrocyclones achieved much less contrast in density between the low and high density discharges, but consistently resulted in a beneficial increase in the stability of the mud emulsion in all of the flow streams and had more desirable rheological properties. A qualitative comparison indicates that the hydrocyclone separation system may offer a feasible and desirable alternative to centrifuge separation system.

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Experimental Study on Critical Displacement for Drill-Conductor Injection during Deepwater Drilling

SPE Journal ◽

10.2118/201226-pa ◽

2020 ◽

Vol 25 (05) ◽

pp. 2206-2219

Author(s):

Changbin Kan ◽

Deli Gao ◽

Jin Yang

Keyword(s):

Experimental Data ◽

Recovery Time ◽

Field Experiments ◽

Drilling Fluid ◽

Injection Rate ◽

Circulation Rate ◽

Stress Recovery ◽

Critical Displacement ◽

Deepwater Drilling ◽

Soil Stress

Summary Drill-conductor-jetting technology is a high-efficiency, good-adaptability, and low-cost technology that has been widely applied in deepwater drilling. However, a reaming effect will be produced easily because of jet breaking and bit rotation during the jetting process, and the critical displacement would be notably affected. Also, it will experience a relatively short soaking time after installation because of the requirements of drilling timeliness, which is an important factor on the bearing safety of a conductor. Therefore, it is meaningful to study the influencing factors of construction conditions and establish a model for evaluating the value of critical displacement. In this study, field experiments on critical displacement for simulating the deepwater-drilling conditions were conducted. By analyzing the drilling hydraulic factors, the effects of soil-stress-recovery time, and the injection rate of pipe, the influence laws of different factors were obtained. The results suggest that the critical displacement increases linearly as the circulation rate of the drilling fluid increases, decreases exponentially with the increase of soil-stress-recovery time, and decreases linearly with the increase of injection rate. One model for estimating the critical displacement using experimental data and the least-squares method was proposed. The predictions showed good agreement with experimental data within suitable ranges of models. This work is expected to provide the basis for predicting conductor stability and wellhead-bearing settlement.

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Comprehensive Hydromechanical Specific Energy Calculation for Drilling Efficiency

Journal of Energy Resources Technology ◽

10.1115/1.4028272 ◽

2014 ◽

Vol 137 (1) ◽

Cited By ~ 13

Author(s):

Kshitij Mohan ◽

Faraaz Adil ◽

Robello Samuel

Keyword(s):

Specific Energy ◽

Drilling Fluid ◽

Mechanical Energy ◽

Energy Calculation ◽

Energy Term ◽

Modeling And Analysis ◽

Mechanical Specific Energy ◽

Available Energy ◽

Jet Impact ◽

Drilling Conditions

Over the last few years, different types of bits have been introduced to meet the challenges of steerable as well as rotary steerable systems; and it is imperative that bits be utilized optimally in these systems. As challenges increase with increasing depths, it becomes even more important for one to efficiently utilize the available energy (Robello, S., 2013, “Modeling and Analysis of Drillstring Vibration in Riserless Environment,” ASME J. Energy Res. Technol., 135(1), p. 013101). A new correlation identifying inefficient drilling conditions is presented in this paper. Mechanical specific energy (MSE) has been used to improve drilling rates, with mixed results. Hydro MSE (HMSE), which is introduced here, encompasses hydraulic as well as mechanical energy. HMSE quantifies the amount of energy required to drill a unit volume of rock and remove it from underneath the bit. HMSE includes axial, torsional, and hydraulic energy and is different from MSE because it includes a hydraulic term. The initial MSE correlation (Teale, R., 1965, “The Concept of Specific Energy in Rock Drilling,” Int. J. Rock Mech. Min. Sci., 2, pp. 57–73.) was modified to accommodate the new hydraulic term. This paper attempts to better model downhole drilling by introducing the hydraulic energy term in the MSE correlation by defining it as HMSE. While the majority of the drilling occurs because of the bit, it is a well-known fact that some drilling occurs due to the “jet impact impingement” caused by the drilling fluid as well. Experimental and field data presented in this paper show that HMSE can identify inefficient drilling conditions. The new hydraulic term included in the specific energy correlation is the key to correctly match the amount of energy required to drill and overcome the strength and stresses of formation being drilled. Also, this new term illustrates how much hydraulic energy is needed to drill faster when the mechanical energy (axial and torsional) is increased. The results also show the importance of including the bit hydraulic energy term into any specific energy analysis for drilling optimization. Field results reveal specific patterns for inefficient drilling conditions and also reveal a good correlation between calculated HMSE and the expected requirements for rock removal under existent conditions of stress at the bit face (Mohan, K., and Robello Samuel, F. A., 2009, “Tracking Drilling Efficiency Using Hydro-Mechanical Specific Energy,” SPE/IADC Drilling Conference and Exhibition, March 17–19, Amsterdam, The Netherlands, No. SPE 119421).

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