Experimental Investigation of Wellbore Fluid Displacement in Concentric and Eccentric Annulus

2017 ◽  
Author(s):  
Jan David Ytrehus ◽  
Bjørnar Lund ◽  
Ali Taghipour ◽  
Shreyansh Divyankar ◽  
Arild Saasen
Keyword(s):  
Test Section ◽  
Drilling Fluid ◽  
Realistic Model ◽  
Outer Diameter ◽  
Cement Slurry ◽  
Fluid Displacement ◽  
Eccentric Annulus ◽  
Production Phase ◽  
Concentric Annulus ◽  
Displacement Front

One of the most critical operations during well construction is the cementing procedure. Due to the curing nature of the cement slurry there will be only one opportunity to cement the well properly. Although one for top hole cases can fill cement in from the top in a remedial operation, this possibility cannot fully compensate for a non-optimal initial cement job. Furthermore, it cannot be applied to other well sections. In those sections, complex squeeze cementing operations may be necessary. Consequences of improper annular cement can be leakage during production phase and extensive costs when the well is to be plugged for abandonment after the production phase. To ensure that the risk of poor cement is minimised it is important to use the best procedures to place the cement properly. To be able to select the optimum procedures, it is necessary to improve the understanding of the displacement in the wellbore annulus. All wells will be cemented in several sections. Findings and improvements that can reduce risk of poor cementing results are thus highly relevant for a large number of operations every year. The article is based on analysing experimental results that illustrates a drilling fluid being displaced by a cement slurry. These fluids are represented by realistic model fluids and circulated through a transparent annular section. The geometry used is a 6,5″outer diameter with an inner string of 5″that also can rotate. The selected pipe sizes may normally be found in the lower parts of a well and often in deviated sections where the inner pipe cannot be assumed concentric at all times. Both concentric and eccentric inner pipe positions have therefore been selected. The test section was run both in horizontal and in inclined position. The test section was 10 meters long and instrumented with conductivity probes in an array around the perimeter at 4 separate positions along the pipe. Together with cameras along the test section the fluid interphases was observed along the test section. Results presented in the article show that inner string rotation provides a steeper displacement front, On the other hand such rotation will also cause more mixing at the interphase. Results also show that the displacement front in a concentric annulus is significantly affected by gravity. While for an eccentric annulus, with the low side at the bottom, the narrow gap is poorly displaced when realistic fluids are applied. It was also observed that the displacement front in concentric annulus was more stable when the test section was inclined than in horizontal position.

Fluid-Fluid Displacement for Primary Cementing in Deviated Washout Sections

2018 ◽  
Author(s):  
Bjørnar Lund ◽  
Jan David Ytrehus ◽  
Ali Taghipour ◽  
Shreyansh Divyankar ◽  
Arild Saasen
Keyword(s):  
Test Section ◽  
Drilling Fluid ◽  
Outer Diameter ◽  
Cement Slurry ◽  
Flow Loop ◽  
Flow Area ◽  
Fluid Displacement ◽  
Production Phase ◽  
Displacement Front ◽  
Annular Section

One of the most critical operations during well construction is the cementing procedure, where drilling fluid is displaced by cement, normally with one or more spacer fluids in between. Due to the curing nature of the cement slurry there will be only one opportunity to cement the well properly. Although one for top hole cases can fill cement in from the top in a remedial operation, this possibility cannot fully compensate for a non-optimal initial cement job. Furthermore, it cannot be applied to other well sections. In those sections, complex squeeze cementing operations may be necessary. Consequences of improper annular cement can be leakage during production phase and extensive costs when the well is to be plugged for abandonment after the production phase. To ensure that the risk of poor cement is minimised it is important to use the best procedures to place the cement properly. Most models in use assume that the annulus is homogeneous. This is not always the case since washout sections appear during drilling. The effects of these on cementing are not sufficiently studied and considered in models and procedures. Here we present and discuss results from fluid displacement experiments in a laboratory flow loop, illustrating annular displacement of drilling fluid by spacer (or spacer by cement). Model fluids with realistic densities and rheological properties have been used in a test setup with a transparent annular section. The wellbore is represented by a 10 m long test section, where the annulus has a 6,5” outer diameter and an inner string of 5” that can rotate. A washout section is represented by a 2 m long section of the outer pipe with a larger diameter of 11”. These diameters are representative for the lower parts of a well were high wellbore inclinations are common. In these sections the inner pipe cannot be assumed concentric at all times, so both concentric and eccentric positions have been tested. Experiments reported here were conducted at 60 degrees inclination. The test section was instrumented with conductivity probes in an array around the perimeter at 4 separate positions along the pipe, including the inlet and outlet of the washout section. Together with a camera along the test section, this provided information about the motion and shape of the liquid-liquid interface through the test section. Results show that the displacement front changes significantly when entering the washout zone compared to the regular annular section. Due to the larger flow area the density differences between displaced and displacing fluids become more important in the washout section, while momentum effects dominate in the regular section.

scholarly journals Effect of Buoyancy and Inertia on Viscoplastic Fluid–Fluid Displacements in a Regular and an Irregular Eccentric Annulus

2020 ◽  
Vol 143 (6) ◽  
Author(s):  
Hans Joakim Skadsem ◽  
Steinar Kragset
Keyword(s):  
Drilling Fluid ◽  
Mass Density ◽  
Three Dimensional ◽  
Density Difference ◽  
Viscoplastic Fluid ◽  
Positive Density ◽  
Displacement Efficiency ◽  
Cement Slurry ◽  
Eccentric Annulus ◽  
Narrow Side

Abstract Casing strings and liners are important subsurface structural components in petroleum and in geothermal wells. After the casing string has been run in hole, it is cemented to the formation by pumping a sequence of spacer fluids and cement slurry into the annulus outside the string. Spacer fluids are usually pumped ahead of the cement slurry to displace the drilling fluid from the annulus that is to be cemented and thereby avoid contamination of the cement slurry. Fluid displacements are governed by inertia, buoyancy, and viscosity effects, in addition to being strongly influenced by the annular geometry. Poor centralization of the casing or irregularities such as washouts can influence the displacement flows both locally and over long axial distances. We present three-dimensional numerical simulations of the displacement flow involving two viscoplastic fluids in the vicinity of a symmetric local hole enlargement. We focus on laminar flow regimes in the regular part of the annulus and investigate how the volumetric flowrate and the mass density difference between the fluids affect the displacement efficiency in the regular and the irregular parts of the annulus. This study considers viscoplastic displacement flows in a near-vertical, irregular annulus and is an extension of a previous publication that focused on a near-horizontal annulus. We contextualize our simulations by comparison to industry guidelines for effective and steady laminar displacements in the regular, near-vertical annulus. Here, eccentricity favors flow in the wider sector of the annulus, while a positive density difference between the fluids generates secondary, azimuthal flow toward the narrow side of the annulus. In the enlarged and irregular section, both the axial bulk velocity and casing eccentricity decrease sharply and buoyancy becomes more pronounced compared to in the regular annulus. We quantify and discuss the effects of local hole enlargements on displacement efficiencies. Simulations of cementing flows can aid in optimizing fluid properties and pump rates, including when the wellbore has suspected or confirmed zones of irregular geometries.

Solidifying Mud Cake to Improve Cementing Quality of Shale Gas Well: A Case Study

2015 ◽  
Vol 8 (1) ◽  
pp. 149-154 ◽  
Author(s):  
Jun Gu ◽  
Ju Huang ◽  
Su Zhang ◽  
Xinzhong Hu ◽  
Hangxiang Gao ◽  
...  
Keyword(s):  
Shale Gas ◽  
Calcium Silicate Hydrate ◽  
Drilling Fluid ◽  
Cement Slurry ◽  
Gas Well ◽  
Safety Requirements ◽  
Mud Cake ◽  
Gas Bearing

The purpose of this study is to improve the cementing quality of shale gas well by mud cake solidification, as well as to provide the better annular isolation for its hydraulic fracturing development. Based on the self-established experimental method and API RP 10, the effects of mud cake solidifiers on the shear strength at cement-interlayer interface (SSCFI) were evaluated. After curing for 3, 7, 15 and 30 days, SSCFI was remarkably improved by 629.03%, 222.37%, 241.43% and 273.33%, respectively, compared with the original technology. Moreover, the compatibility among the mud cake solidifier, cement slurry, drilling fluid and prepad fluid meets the safety requirements for cementing operation. An application example in a shale gas well (Yuanye HF-1) was also presented. The high quality ratio of cementing quality is 93.49% of the whole well section, while the unqualified ratio of adjacent well (Yuanba 9) is 84.46%. Moreover, the cementing quality of six gas-bearing reservoirs is high. This paper also discussed the mechanism of mud cake solidification. The reactions among H3AlO42- and H3SiO4- from alkali-dissolved reaction, Na+ and H3SiO4- in the mud cake solidifiers, and Ca2+ and OH- from cement slurry form the natrolite and calcium silicate hydrate (C-S-H) with different silicate-calcium ratio. Based on these, SSCFI and cementing quality were improved.

The Research and Application of Cementing Isolation Technology in High Porosity and Permeability of Developed Clastic Rock Reservoir in Tarim Basin

2021 ◽  
Author(s):  
Hongtao Liu ◽  
Zhengqing Ai ◽  
Jingcheng Zhang ◽  
Zhongtao Yuan ◽  
Jianguo Zeng ◽  
...  
Keyword(s):  
Drilling Fluid ◽  
Water Layer ◽  
High Porosity ◽  
Self Healing ◽  
Cement Slurry ◽  
Clastic Rock ◽  
Pump Rate ◽  
Porosity And Permeability ◽  
Zonal Isolation ◽  
High Pump

Abstract The average porosity and permeability in the developed clastic rock reservoir in Tarim oilfield in China is 22.16% and 689.85×10-3 μm2. The isolation layer thickness between water layer and oil layer is less than 2 meters. The pressure of oil layer is 0.99 g/cm3, and the pressure of bottom water layer is 1.22 g/cm3, the pressure difference between them is as bigger as 12 to 23 MPa. It is difficult to achieve the layer isolation between the water layer and oil layer. To solve the zonal isolation difficulty and reduce permeable loss risk in clastic reservoir with high porosity and permeability, matrix anti-invasion additive, self-innovate plugging ability material of slurry, self-healing slurry, open-hole packer outside the casing, design and control technology of cement slurry performance, optimizing casing centralizer location technology and displacement with high pump rate has been developed and successfully applied. The results show that: First, the additive with physical and chemical crosslinking structure matrix anti-invasion is developed. The additive has the characteristics of anti-dilution, low thixotropy, low water loss and short transition, and can seal the water layer quickly. Second, the plugging material in the slurry has a better plugging performance and could reduce the permeability of artificial core by 70-80% in the testing evaluation. Third, the self-healing cement slurry system can quickly seal the fracture and prevent the fluid from flowing, and can ensuring the long-term effective sealing of the reservoir. Fourth, By strict control of the thickening time (operation time) and consistency (20-25 Bc), the cement slurry can realize zonal isolation quickly, which has achieved the purpose of quickly sealing off the water layer and reduced the risk of permeable loss. And the casing centralizers are used to ensure that the standoff ratio of oil and water layer is above 67%. The displacement with high pump rate (2 m3/min, to ensure the annular return velocity more than 1.2 m/s) can efficiently clean the wellbore by diluting the drilling fluid and washing the mud cake, and can improve the displacement efficiency. The cementing technology has been successfully applied in 100 wells in Tarim Oilfield. The qualification rate and high quality rate is 87.9% and 69% in 2019, and achieve zone isolation. No water has been produced after the oil testing and the water content has decreased to 7% after production. With the cementing technology, we have improved zonal isolation, increased the crude oil production and increased the benefit of oil.

Full Scale Flow Loop Experiments of Hole Cleaning Performances of Drilling Fluids

2015 ◽  
Author(s):  
Jan David Ytrehus ◽  
Ali Taghipour ◽  
Sneha Sayindla ◽  
Bjørnar Lund ◽  
Benjamin Werner ◽  
...  
Keyword(s):  
Test Section ◽  
Drilling Fluid ◽  
Drilling Fluids ◽  
Flow Loop ◽  
Base Oil ◽  
Hole Cleaning ◽  
Cleaning Performance ◽  
Water Based ◽  
Fluid Properties ◽  
Drilling Cost

One important requirement for a drilling fluid is the ability to transport the cuttings out of the borehole. Improved hole cleaning is a key to solve several challenges in the drilling industry and will allow both longer wells and improved quality of well construction. It has been observed, however, that drilling fluids with similar properties according to the API standard can have significantly different behavior with respect to hole cleaning performance. The reasons for this are not fully understood. This paper presents results from flow loop laboratory tests without and with injected cuttings size particles using a base oil and a commercial oil based drilling fluid. The results demonstrate the importance of the rheological properties of the fluids for the hole cleaning performance. A thorough investigation of the viscoelastic properties of the fluids was performed with a Fann viscometer and a Paar-Physica rheometer, and was used to interpret the results from the flow loop experiments. Improved understanding of the fluid properties relevant to hole cleaning performance will help develop better models of wellbore hydraulics used in planning of well operations. Eventually this may lead to higher ROP with water based drilling fluids as obtained with oil based drilling fluids. This may ease cuttings handling in many operations and thereby significantly reduce the drilling cost using (normally) more environmentally friendly fluids. The experiments have been conducted as part of an industry-sponsored research project where understanding the hole cleaning performance of various oil and water based drilling fluids is the aim. The experiments have been performed under realistic conditions. The flow loop includes a 10 meter long test section with 2″ OD freely rotating drillstring inside a 4″ ID wellbore made of concrete. Sand particles were injected while circulating the drilling fluid through the test section in horizontal position.

Flow Loop Investigation of Lubricant Concentration Effect on Mechanical Friction in Drilling Fluids

2016 ◽  
Author(s):  
Jan David Ytrehus ◽  
Ali Taghipour ◽  
Knud Richard Gyland ◽  
Bjørnar Lund ◽  
Sneha Sayindla ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
North Sea ◽  
Test Section ◽  
Drilling Fluid ◽  
Drill String ◽  
Drilling Fluids ◽  
Flow Loop ◽  
Steel Tubing ◽  
Steel Sections ◽  
Concrete Elements

A laboratory scale flow loop for drilling applications has been used for evaluating the effect of lubricants on skin friction during drilling and completion with oil based or low solids oil based fluids. The flow loop included a 10 meter long test section with 2″ OD free whirling rotating drill string inside a 4″ ID wellbore made of concrete elements positioned inside a steel tubing. A transparent part of the housing was located in the middle of the test section, separating two steel sections of equal length. The entire test section was mounted on a steel frame which can be tilted from horizontal to 30° inclination. The drilling fluids and additives in these experiments were similar to those used in specific fields in NCS. Friction coefficient was calculated from the measured torque for different flow velocities and rotational velocities and the force perpendicular to the surface caused by the buoyed weight of the string. The main objective of the article has been to quantify the effect on mechanical friction when applying different concentrations of an oil-based lubricant into an ordinary oil based drilling fluid and a low solids oil based drilling fluid used in a North Sea drilling and completion operation.

scholarly journals Effect of Surface Wettability on Immiscible Displacement in a Microfluidic Porous Media

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 664 ◽  
Author(s):  
Jorge Avendaño ◽  
Nicolle Lima ◽  
Antonio Quevedo ◽  
Marcio Carvalho
Keyword(s):  
Porous Media ◽  
Water Injection ◽  
Residual Oil ◽  
Strong Function ◽  
Fluid Displacement ◽  
Oil Displacement ◽  
Displacement Front ◽  
Final Volume ◽  
Displacement Experiments ◽  
Effect Of Surface

Wettability has a dramatic impact on fluid displacement in porous media. The pore level physics of one liquid being displaced by another is a strong function of the wetting characteristics of the channel walls. However, the quantification of the effect is still not clear. Conflicting data have shown that in some oil displacement experiments in rocks, the volume of trapped oil falls as the porous media becomes less water-wet, while in some microfluidic experiments the volume of residual oil is higher in oil-wet media. The reasons for this discrepancy are not fully understood. In this study, we analyzed oil displacement by water injection in two microfluidic porous media with different wettability characteristics that had capillaries with constrictions. The resulting oil ganglia size distribution at the end of water injection was quantified by image processing. The results show that in the oil-wet porous media, the displacement front was more uniform and the final volume of remaining oil was smaller, with a much smaller number of large oil ganglia and a larger number of small oil ganglia, when compared to the water-wet media.

Numerical and Experimental Analysis of Twisted Tape Insert in Circular Tube

2019 ◽  
Author(s):  
V. S. Chandratre ◽  
A. A. Keste ◽  
N. K. Sane
Keyword(s):  
Heat Flux ◽  
Experimental Analysis ◽  
Test Section ◽  
Circular Tube ◽  
Uniform Heat Flux ◽  
Internal Diameter ◽  
Twisted Tape ◽  
Outer Diameter ◽  
Nusselt Numbers ◽  
Area Of Concern

Abstract Energy is a major area of concern for many industrial and engineering applications. For the development of energy efficient heat exchangers, heat transfer enhancement by passive inserts have growing research potential. The present study gives the numerical and experimental analysis of twisted tape insert in a circular tube for the range of Reynolds number between 5000 to 15000 with heat flux variation from 500W/m2 to 1.5 kW/m2 with air as working medium. A circular tube of 52.5 mm internal diameter, 60 mm outer diameter and 1000 mm length is used as test section with uniform heat flux. Twisted tape used is of Aluminum material having a pitch of 100 mm. Outside surface temperatures are measured at different locations on test section. Two ‘T’ type thermocouples are used to measure air temperature at inlet and outlet of test section. From numerical and experimental analysis it is observed that the Nusselt number increases for twisted tape as compared to smooth bare tube by 2.2–3.1 times. Again the Nusselt numbers obtained for smooth tube is compared with Dittus-Boelter and Gnielinski correlation and it is observed that the error is within acceptable limit of 10% variation. An error of 10% variation is observed in friction factor obtained by experimental analysis and Blasius and Petukov correlations.

scholarly journals QUENCH FRONT PROPAGATION IN THE ANNULAR CHANNEL

2016 ◽  
Vol 4 ◽  
pp. 97
Author(s):  
Jan Stepanek ◽  
Vaclav Blaha ◽  
Vaclav Dostal
Keyword(s):  
Stainless Steel ◽  
Test Section ◽  
Initial Conditions ◽  
Front Propagation ◽  
Glass Tube ◽  
Annular Channel ◽  
Steel Tube ◽  
Stainless Steel Tube ◽  
Outer Diameter ◽  
Inner Diameter

Understanding the quench front propagation during bottom core reflooding is crucial for the effective cooling during the LOCA accident. The results presented in this paper were obtained on an experimental loop with an annular test section. The test section consists of a vertical electrically heated stainless steel tube with outer diameter 9 mm and length of 1.7 m. The heated tube is placed inside a glass tube with the inner diameter 14.5 mm. Water mass flux during the reflooding is in the range from 100 kg.m<sup>−2</sup>.s<sup>−1</sup> up to 140 kg.m<sup>−2</sup>.s<sup>−1</sup> and the initial wall temperature of the stainless steel tube is in the range from 250 °C up to 800 °C. The presented results show the influence of the initial conditions on the quench front propagation and the complexity of the phenomenon.

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