The authors would like to thank the following people and institutions for their help and support: William Portas and James Heathman (Industry Advisors, Shell E&#38;P), Richard Littlefield and Rodney Pennington (Shell Westhollow Technology Center), Daniele di Crescenzo (Shell Research Well Engineer), Bill Carruthers (LaFarge), Tim Quirk (now with Chevron), Gerry Masterman and Wayne Manuel (LSU PERTT Lab), Rick Young (LSU Rock Mechanics Lab), and members of the SEER Lab (Arome Oyibo, Tao Tao, and Iordan Bossev).

1. Composite Sample (Figure 1)
NOTE: Most cement jobs in the Gulf of Mexico (USA) are done using Class H cement18, therefore, the same type of cement was used to perform the lab experiments to simulate field-like conditions, the potential applicability of this technology for SCP remediation in the Gulf of Mexico.
<ol>
	<li>Sample preparation 
	NOTE: The 61-cm long sample consists of two grade B electrically resisted welded (ERW) carbon steel pipes (Figure 1). The inner pipe is 61 cm long and has a 6 cm outside diameter (OD) with 2.8 mm wall thickness. The outer pipe is 59.7 cm long, has 10 cm OD and a wall thickness of 5.7 mm. Yield strength and tensile strength of the pipes are 241 MPa and 414 MPa, respectively.
	<ol>
		<li>Drill 12 holes of 2.4 mm on the outer pipe to provide the relief of pressure during expansion and mimic porosity of rocks in field conditions. Drill eight 8.6 mm holes next on the outer pipe, 90&#176; apart with four holes 13 cm from the top and four holes 53 cm from the top.</li>
		<li>Thread these holes with 3.2 mm NPT (National Pipe Thread) threading tip to allow connection with pipe fittings and nylon tubing manifold assembly on the bottom (inlet) and top (outlet) side of the sample. Ensure that the inlet and outlet ports are 40.64 cm apart and are used for running of pre- and post-expansion multi-rate gas flow-through experiments.</li>
		<li>Coat outer pipe with anti-corrosion spray to prevent corrosion during the curing period which could interfere with the experiments due to formation of iron hydroxide and corrosion products could cause microfracturing of cement. 
		NOTE: This scenario will be tested in the future experiments as corrosion of metal is often present in wellbore systems.</li>
		<li>Machine out the welding bead on the inside wall of the inner pipe.</li>
		<li>Cut custom-made steel coupling to a length of 4.5 cm, from 6.35 cm OD pipe. Thread the piece on the inside wall and weld it to the 0.63 cm thick steel plate ring (Figure 2). Thread the bottom part of the inner pipe on the outside wall in length of 4.5 cm to allow connection with the welded coupling, as shown in Figure 2.</li>
		<li>Weld the outer pipe to the steel plate ring.</li>
		<li>Lubricate the inner pipe&#8217;s outside wall with petroleum jelly and baking spray along its entire length. Screw the inner pipe into the coupling to finish the composite sample assembly.</li>
		<li>Cement the volume between inner and outer pipes with 1.57 g/cm3 cement slurry, 0.87 w/c ratio.</li>
		<li>Cure samples in a water bath at ambient conditions for a minimum period of 28 days. Keep the pH of the water bath between 12 and 13 by adding Ca(OH)2 to the water to maintain high pH environment.</li>
	</ol>
	</li>
	<li>Preparation of 13.1 lb/gal cement slurry (for volume of 2.2 L)
	<ol>
		<li>Pour 1,350 g of water into the 4 L, 3.75 horsepower laboratory blender and pre-hydrate 30 g (2% by weight of cement) of bentonite for 5 min on low speed (30,000 x g).</li>
		<li>After 5 min, pour 5 ml of defoaming agent and 1,500 g of cement powder into the blender and shear for 40 sec on high speed of 51,755 x g. Pour the cement slurry into the annulus of the pipe assembly and cover with a wet cloth and plastic wrap to avoid exposure to air and prevent carbonation of cement.</li>
		<li>Six hours after the cement slurry is poured between the pipes, rotate the inner pipe a quarter-turn back and forth every 15 min for the next 20 hr of cement hydration to prevent cement bonding with the inner pipe and create a microchannel (required for microannular gas flow).</li>
		<li>Place the cemented composite sample horizontally in the water bath for a minimum period of 28 days. Ensure that the water bath has a pH value of around 13 which is achieved by adding 100 g of Ca(OH)2 into 20 L of water.</li>
	</ol>
	</li>
</ol>
2. Pre-expansion Flow-through Experiments
<ol>
	<li>Screw 3.2 mm fittings into four inlet and outlet ports on the outer pipe of the sample. Connect inlet and outlet manifolds with pressure transducers to the fittings (Figure 5).</li>
	<li>Pressurize gas cylinder to initial inlet pressure of 50 kPa. Turn on computer software to record pressures.</li>
	<li>Open the flow meter and begin the flow-through test. Monitor inlet and outlet pressures on the screen for 1 min, as shown in Figure 6.</li>
	<li>Pressurize gas cylinder to inlet pressure of 172 kPa and monitor the pressure for another 2 min.</li>
	<li>End flow-through experiment and pressure recording. Close the gas cylinder and vent the remaining gas into the atmosphere. Dismantle the manifolds and cover top of the sample with wet cloth while powering the expansion unit, to prevent carbonation and drying of cement.</li>
	<li>Coat the inside wall of the inner pipe with lubricant for smooth running of the expansion cone and the sample is ready for expansion.</li>
</ol>
3. Expansion Setup and Expansion Procedure
<ol>
	<li>Fully retain the expansion mandrel from the lower housing by the hydraulic cylinder, as shown in Figure 4a. Place the composite sample with hydrated cement in the lower sample housing of the fixture through the opening at the top (Figure 4b).</li>
	<li>Fully elongate the expansion mandrel through the sample after which the expansion cone with desired expansion ratio (Figure 3) is slipped onto it, as shown in Figure 4c. Screw the retaining mandrel onto expansion mandrel, then screw the retaining mandrel guide onto the lower connector of the lower housing. The sample is ready for expansion.</li>
	<li>Power the hydraulic unit to an optimum pressure of 10.3 MPa, and turn on the computer software for axial force recording.</li>
	<li>Activate the control switch to retract the expansion mandrel and pull the expansion through the inner pipe of the sample, thus expanding the pipe and compressing the cement sheath. Expand samples to the length of 40.64 cm (Figure 4d) and then elongate the expansion mandrel into original position. Stop recording of axial forces.</li>
	<li>Unscrew the retaining mandrel guide and remove the retaining mandrel. Take off the expansion cone from the expansion mandrel and fully retract the mandrel in order to remove the sample form the lower housing.</li>
	<li>After the sample is removed, prepare it for post-expansion multi-rate gas flow-through experiments.</li>
</ol>
4. Post-expansion Multi-rate Flow-through Experiments
<ol>
	<li>Clean inlet and outlet ports from any excess of squeezed cement paste.</li>
	<li>Screw pipe fittings into four inlet and outlet ports on the outer pipe of the sample. Connect inlet and outlet manifolds to the fittings, as shown in Figure 5.</li>
	<li>Pressure the gas cylinder to initial inlet pressure of 172 kPa. Turn on computer software to record pressures.</li>
	<li>Open the flow meter and begin the flow-through test. Monitor inlet and outlet pressures on the screen (Figure 6).</li>
	<li>After 5 min, pressurize the gas cylinder to inlet pressure of 345 kPa and monitor the pressures for another 5 min.</li>
	<li>After 5 min increase the inlet pressure to 517 kPa.</li>
	<li>After 5 min increase the inlet pressure to final inlet pressure of 690 kPa for another 5 min.</li>
	<li>End the flow-through experiment and pressure recording. Close the gas cylinder and vent the remaining gas into the atmosphere. Dismantle manifolds from the sample.</li>
</ol>
5. Calculations of the Effective Permeability of the Microannulus
NOTE: The main purpose of this study was to provide qualitative information regarding existence of gas flow before and after expansion. The experimental design does not possess sophisticated components to be able to measure the width of the channel and flow rate accuracy. During these preliminary experiments sealing of gas flow was the main focus. Therefore, any of permeability calculations shown here are more semi-quantitative and not main goal of the study.
<ol>
	<li>For calculation of the effective permeability, use the constant nitrogen flow rate of approximately q=1.42 cm3/sec upon pressure stabilization. The gas deviation factor for nitrogen at ambient conditions is Z=1 and viscosity &#956;=0.018 cP. Conduct all the flow-through tests at ambient conditions of T=535 &#186;R.</li>
	<li>Calculate the area of the cemented annular space by taking inner radius of the outer pipe, rOinn=4.6 cm, and outer radius of the inner pipe, rIout=3.05 cm. The distance between inlet and outlet ports (&#916;L) is 40.64 cm. Pressure differential (Pinlet-Poutlet), recorded by inlet and outlet pressure transducers, is the only variable used in calculations of effective permeability of the pre-manufactured microannulus (Kef)19: 
	<img alt="Equation 1" fo:content-width="2in" src="/files/ftp_upload/52098/52098eq1.jpg" />&#160; Eq. 1 
	q &#8211; nitrogen flow rate [cm3/sec]&#160;&#160;&#160; Kef &#8211; effective perm. of microannulus [mD] 
	r Iout &#8211; ID of outer pipe [cm]&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; rOinn &#8211; OD of inner pipe [cm] 
	&#181; &#8211; gas viscosity [cP]&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; Z &#8211; gas deviation factor 
	T &#8211; temperature [&#186;R]&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; &#916;L &#8211; distance between pressure transducers [cm] 
	Pinlet &#8211; inlet pressure [atm]&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; Poutlet &#8211; outlet pressure [atm]</li>
	<li>Substitute all of the above values into the Equation 1 and calculate the effective permeability as shown below in Example 1. The inlet pressure recorded during pre-expansion flow-through experiment was Pinlet=12 kPa (0.12 atm) while the outlet pressure transducer was Poutlet=0.4 kPa (0.004 atm). 
	Example 1: <img alt="Equation 2" fo:content-width="3in" src="/files/ftp_upload/52098/52098eq2.jpg" /></li>
</ol>

<ol>
	<li>King, G. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Well+Integrity:+Hydraulic+Fracturing+and+Well+Construction+&#8211;+What+are+the+Factual+Risks.">Well Integrity: Hydraulic Fracturing and Well Construction &#8211; What are the Factual Risks.</a> SPE Wellbore Integrity Webinar. 5, (2013).</li><li>Taylor, H. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Cement Chemistry. , (1997).</li><li>Thiercelin, M. J., Dargaud, B., Baret, J. F., Rodriguez, W. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cement+design+based+on+cement+mechanical+response.">Cement design based on cement mechanical response.</a> SPE Drill &amp; Compl. 13 (4), 266-273 (1998).</li><li>Nelson, E. B., Guillot, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Well Cementing. , (2006).</li><li>Carter, L., Evans, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Study+of+Cement-Pipe+Bonding.">A Study of Cement-Pipe Bonding.</a> Paper SPE 164 presented at the California Regional Meeting. , 24-25 (1964).</li><li>Goodwin, K., Crook, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cement+Sheath+Stress+Failure.">Cement Sheath Stress Failure.</a> SPE Drill Eng. 7 (4), 291-296 (1992).</li><li>Heathman, J., Beck, F. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Finite+Element+Analysis+Couples+Casing+and+Cement+Designs+for+HP/HT+Wells+in+East+Texas.">Finite Element Analysis Couples Casing and Cement Designs for HP/HT Wells in East Texas.</a> Paper SPE 98869 presented at the IADC/SPE Conference. , (2006).</li><li>Boukhelifa, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+Cement+Systems+for+Oil+and+Gas+Well+Zonal+Isolation+in+a+Full-Scale+Annular+Geometry.">Evaluation of Cement Systems for Oil and Gas Well Zonal Isolation in a Full-Scale Annular Geometry.</a> Paper SPE 87195 presented at the IADC/SPE Drilling Conference. , (2004).</li><li>Duan, S., Wojtanowicz, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Method+for+Evaluation+of+Risk+of+Continuous+Air+Emissions+from+Sustained+Casinghead+Pressure.">A Method for Evaluation of Risk of Continuous Air Emissions from Sustained Casinghead Pressure.</a> Paper SPE 94455 presented at SPE/EPA/DOE Exploration and Production Environmental Conference. , (2005).</li><li>Watson, T. L., Bachu, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+the+potential+for+gas+and+CO2+leakage+along+wellbores.">Evaluation of the potential for gas and CO2 leakage along wellbores.</a> SPE Drill &amp; Compl. 24 (1), 115-126 (2009).</li><li>Wojtanowicz, A. K., Nishikawa, S., Xu, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diagnosis+and+remediation+of+SCP+in+wells.">Diagnosis and remediation of SCP in wells.</a> Final report submitted to US Department of Interior MMS. , (2001).</li><li>Kupresan, D., Heathman, J., Radonjic, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Experimental+Assessment+of+Casing+Expansion+as+a+Solution+to+Microannular+Gas+Migration.">Experimental Assessment of Casing Expansion as a Solution to Microannular Gas Migration.</a> Paper SPE 168056 presented at IADC/SPE Drilling Conference and Exhibition. , (2014).</li><li>Kupresan, D., Heathman, J., Radonjic, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+a+New+Physical+Model+of+Expandable+Casing+Technology+in+Mitigation+of+Wellbore+Leaks.">Application of a New Physical Model of Expandable Casing Technology in Mitigation of Wellbore Leaks.</a> CETI Journal. 1 (5), 21-24 (2013).</li><li>Demong, K., Rivenbark, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Breakthroughs+using+Solid+Expandable+Tubulars+to+Construct+Extended+Reach+Wells.">Breakthroughs using Solid Expandable Tubulars to Construct Extended Reach Wells.</a> Paper SPE 87209 presented at the IADC/SPE Drilling Conference. , (2004).</li><li>Grant, T., Bullock, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+evolution+of+Solid+Expandable+Tubular+Technology:+Lessons+Learned+Over+Five+Years.">The evolution of Solid Expandable Tubular Technology: Lessons Learned Over Five Years.</a> , (2005).</li><li>Jennings, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dynamic+formations+rendered+less+problematic+with+solid+expandable+technology.">Dynamic formations rendered less problematic with solid expandable technology.</a> , (2008).</li><li>Fanguy, C., Mueller, D., Doherty, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improved+method+of+cementing+solid+expandable+tubulars.">Improved method of cementing solid expandable tubulars.</a> , (2004).</li><li>American Petroleum Institute. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Appendix+C+(tentative),+Fluid+Density+Balance.">Appendix C (tentative), Fluid Density Balance.</a> Recommended Practice for Testing Oilwell Cements and Cement Additives. , (1971).</li><li>Nelson, E. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Well cementing. , (1990).</li></ol>

The authors have nothing to disclose.

The reported experimental procedure has two main components that are critical: composite cylinders that simulate wellbores and the expansion fixture that is used to carry out mechanical manipulation of cement. When designing wellbore models (cement/pipe composite cylinders), it is critical to choose adequate cement density, store samples under total humidity conditions (100% RH) and establish pipe-cement debonding before cement slurry completely sets. Failing to achieve this would make the entire gas flow experiment impo...

The reported experimental procedure has two main components that are critical: composite cylinders that simulate wellbores and the expansion fixture that is used to carry out mechanical manipulation of the cement.
Wellbores are the main gateway for production of subsurface fluids (water, oil, gas, or steam) as well as injection of various fluids. Regardless of its function, the wellbore is required to provide a controlled flow of produced/injected fluids. Wellbore construction has two distinct operations: drilling and completion. Wellbore cement, part of the completions procedure, primarily provides zonal isolation, mechanical support of the metal pipe (casing), and protection of metal components from corrosive fluids. These are essential elements of uncompromised, fully functioning wellbores. The integrity of the wellbore cement sheath is a function of the chemical and physical properties of the hydrated cement, the geometry of the cased well, and the properties of the surrounding formation/formation fluids2,3. Incomplete removal of drilling fluid will result in poor zonal isolation since it prevents formation of strong bonds at interfaces with rock and/or metal. Cement sheaths can be subjected to many types of failure during the life of a well. Pressure and temperature oscillations caused by completion and production operations contribute to the development of fractures within the cement matrix; debonding is caused by pressure and/or temperature changes and cement hydration shrinkage4,5,6. The result is almost always presence of microannular fluid flow, although its occurrence can be detected early or after years of service life.
Heathman and Beck (2006) created a model of cemented casing subjected to over 100 pressure and temperature cyclic loads, which showed visible debonding, initiation of cement cracks which can pose preferential pathways for migrating fluid7. In the field, the expansion and contraction of metal components of a wellbore will not coincide with those of cement and rock, causing interfacial debonding and formation of a microannulus, leading to an increase in permeability of the cement sheath. An additional casing loading can cause the propagation of radial cracks in the cement matrix once the tensile stresses exceed the tensile strength of the material8. All of the aforementioned cement failures can result in micro-channeling, which leads to gas migration, the occurrence of SCP, and long-term environmental risks.
A considerable number of producing and abandoned wells with SCP constitute a potentially new source of continuous natural gas emission9. The analysis conducted by Watson and Bachu (2009) of 315,000 oil, gas, and injection wells in Alberta, Canada also showed that wellbore deviation, well type, abandonment method, and the quality of cement are key factors contributing to potential well leakage in the shallower part of the well10. The existing remedial operations are costly and unsuccessful; the squeeze cementing, one of the most commonly used remedial techniques, has a success rate of just 50%11.
In this paper we report on the evaluation of the Expandable Casing Technology (ECT) as a new remediation technique for leaky wellbores12,13. ECT can be applied in new or existing wells14. The first commercial installation of this technology was performed by Chevron on a well in shallow waters of the Gulf of Mexico in November 1999 15. The current operating envelope for expandable tubulars encapsulates an inclination of 100&#176; from vertical, temperature up to 205 &#176;C, mud weight to 2.37 g/cm3, a depth of 8,763 m, hydrostatic pressure of 160.6 GPa and a tubular length 2,092 m 16. A typical expansion rate for solid expandable tubulars is approximately 2.4 m/min 17.
This study offers a unique approach to the adaptation of ECT technology as a new remediation operation for SCP. The expansion of the steel pipe compresses the cement which would result in closure of the gas flow at the interface and seal the gas leak. It is important to mention that the focus of this study is the sealing of an existing microannular gas flow, therefore we only focused on that as a possible cause of leaky wellbores. In order to test the effectiveness of newly adapted technology for this purpose, we designed a wellbore model with an existing microannular flow. This is obtained by rotating the inner pipe during cement hydration. This is not to simulate any field operations, but simply to fast-forward what would happen after decades of thermal and pressure loading in a wellbore.

<table border="0" cellpadding="0" cellspacing="0" width="742">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:341px;">ASTM A53 Grade B ERW Schedule 40 Steel pipe - OD=10.16 cm, ID=10.04 cm, L=59.7 cm</td>
			<td style="width:108px;">Baker Sales</td>
			<td style="width:119px;">BPE-4.00BB40</td>
			<td></td>
		</tr>
		<tr height="50">
			<td height="50" style="height:50px;width:341px;">ASTM A53 Grade B ERW Schedule 10 Steel pipe - OD=6 cm, ID=5.94 cm, L=61 cm&#160;</td>
			<td style="width:108px;">Service Steel</td>
			<td style="width:119px;">n/a</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:341px;">Expansion Cones - AISI D2 grade alloy steel (60 RC hardness)</td>
			<td style="width:108px;">Shell</td>
			<td style="width:119px;">Custom-made</td>
			<td></td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;width:341px;">Pipe coupling - OD=6.35 cm, ID=6 cm, L=4.4 cm</td>
			<td style="width:108px;">LSU</td>
			<td style="width:119px;">Custom-made</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:341px;">Steel plate ring - OD=10.16 cm, ID=5.76 cm, thickness=6.35 mm</td>
			<td style="width:108px;">Louisiana Cutting</td>
			<td style="width:119px;">Custom-made</td>
			<td></td>
		</tr>
		<tr height="37">
			<td height="37" style="height:37px;width:341px;">Class H Cement</td>
			<td style="width:108px;">LaFarge</td>
			<td style="width:119px;">04-16-12 / 14-18</td>
			<td></td>
		</tr>
		<tr height="32">
			<td height="32" style="height:32px;width:341px;">Defoaming agent - D-Air 3000L</td>
			<td style="width:108px;">Halliburton</td>
			<td style="width:119px;">n/a</td>
			<td></td>
		</tr>
		<tr height="30">
			<td height="30" style="height:30px;width:341px;">Bentonite clay</td>
			<td style="width:108px;">LSU</td>
			<td style="width:119px;">n/a</td>
			<td></td>
		</tr>
		<tr height="30">
			<td height="30" style="height:30px;width:341px;">Calcium hydroxide</td>
			<td style="width:108px;">LSU</td>
			<td style="width:119px;">n/a</td>
			<td></td>
		</tr>
		<tr height="31">
			<td height="31" style="height:31px;width:341px;">Expansion Fixture</td>
			<td style="width:108px;">Shell</td>
			<td style="width:119px;">Custom-made</td>
			<td></td>
		</tr>
		<tr height="29">
			<td height="29" style="height:29px;width:341px;">Pressure transducers</td>
			<td style="width:108px;">Omega</td>
			<td style="width:119px;">PX480A-200GV&#160;</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:341px;">Teflon tubing</td>
			<td style="width:108px;">Swagelok</td>
			<td style="width:119px;">PB0754100</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:341px;">Union tee</td>
			<td style="width:108px;">Swagelok</td>
			<td style="width:119px;">SS-400-3</td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:341px;">Elbow union</td>
			<td style="width:108px;">Swagelok</td>
			<td style="width:119px;">SS-400-9</td>
			<td></td>
		</tr>
		<tr height="29">
			<td height="29" style="height:29px;width:341px;">Female elbow</td>
			<td style="width:108px;">Swagelok</td>
			<td style="width:119px;">SS-400-8-8</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:341px;">Port connector</td>
			<td style="width:108px;">Swagelok</td>
			<td style="width:119px;">SS-401-PC</td>
			<td></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;width:341px;">Forged body valve</td>
			<td style="width:108px;">Swagelok</td>
			<td style="width:119px;">SS-1RS4</td>
			<td></td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:341px;">Tube adapter</td>
			<td style="width:108px;">Swagelok</td>
			<td style="width:119px;">SS-4-TA-1-2</td>
			<td></td>
		</tr>
		<tr height="45">
			<td height="45" style="height:45px;width:341px;">Pipe lubricant</td>
			<td style="width:108px;">E.F. Houghoton &#38; Co.</td>
			<td>71323998</td>
			<td></td>
		</tr>
		<tr height="30">
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mechanical expansion of steel tubing as a solution to leaky wellbores

Wellbore cement, a procedural component of wellbore completion operations, primarily provides zonal isolation and mechanical support of the metal pipe (casing), and protects metal components from corrosive fluids. These are essential for uncompromised wellbore integrity. Cements can undergo multiple forms of failure, such as debonding at the cement/rock and cement/metal interfaces, fracturing, and defects within the cement matrix. Failures and defects within the cement will ultimately lead to fluid migration, resulting in inter-zonal fluid migration and premature well abandonment. Currently, there are over 1.8 million operating wells worldwide and over one third of these wells have leak related problems defined as Sustained Casing Pressure (SCP)1. 
The focus of this research was to develop an experimental setup at bench-scale to explore the effect of mechanical manipulation of wellbore casing-cement composite samples as a potential technology for the remediation of gas leaks. 
The experimental methodology utilized in this study enabled formation of an impermeable seal at the pipe/cement interface in a simulated wellbore system. Successful nitrogen gas flow-through measurements demonstrated that an existing microannulus was sealed at laboratory experimental conditions and fluid flow prevented by mechanical manipulation of the metal/cement composite sample. Furthermore, this methodology can be applied not only for the remediation of leaky wellbores, but also in plugging and abandonment procedures as well as wellbore completions technology, and potentially preventing negative impacts of wellbores on subsurface and surface environments.

Pre-expansion gas flow-through tests on the composite sample showed pressure recording on the outlet pressure transducer, confirming gas flow through the pre-manufactured microannulus (Figures 7 and 8). Initial conditions were kept the same where initial inlet pressure was 103 kPa and the gas flow rate was kept at 85 ml/min for that period. The time lag in pressure recording between the inlet and outlet pressure transducers was 7.5 seconds, while the highest pressures recorded after incr...

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Mechanical Expansion of Steel Tubing as a Solution to Leaky Wellbores

This article reports on a laboratory scale investigation of an existing field procedure and its adaptation for sealing of leaky wellbores. It consists of mechanical expansion of metal pipe, which results in an improved metal/cement bond, ultimate sealing of hydraulic pathways and prevention of gas leaks caused by the presence of a microannular channel.

Wellbore cement, a procedural component of wellbore completion operations, primarily provides zonal isolation and mechanical support of the metal pipe ...

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12.1K Views.  Louisiana State University. This article reports on a laboratory scale investigation of an existing field procedure and its adaptation for sealing of leaky wellbores. It consists of mechanical expansion of metal pipe, which results in an improved metal/cement bond, ultimate sealing of hydraulic pathways and prevention of gas leaks caused by the presence of a microannular channel.

Video: Mechanical Expansion of Steel Tubing as a Solution to Leaky Wellbores

Synthesis of Phase-shift Nanoemulsions with Narrow Size Distributions for Acoustic Droplet Vaporization and Bubble-enhanced Ultrasound-mediated Ablation

High-intensity focused ultrasound (HIFU) is used clinically to thermally ablate tumors. To enhance localized heating and improve thermal ablation in tumors, lipid-coated perfluorocarbon droplets have been developed which can be vaporized by HIFU. The vasculature in many tumors is abnormally leaky due to their rapid growth, and nanoparticles are able to penetrate the fenestrations and passively accumulate within tumors. Thus, controlling the size of the droplets can result in better accumulation within tumors. In this report, the preparation of stable droplets in a phase-shift nanoemulsion (PSNE) with a narrow size distribution is described. PSNE were synthesized by sonicating a lipid solution in the presence of liquid perfluorocarbon. A narrow size distribution was obtained by extruding the PSNE multiple times using filters with pore sizes of 100 or 200 nm. The size distribution was measured over a 7-day period using dynamic light scattering. Polyacrylamide hydrogels containing PSNE were prepared for in vitro experiments. PSNE droplets in the hydrogels were vaporized with ultrasound and the resulting bubbles enhanced localized heating. Vaporized PSNE enables more rapid heating and also reduces the ultrasound intensity needed for thermal ablation. Thus, PSNE is expected to enhance thermal ablation in tumors, potentially improving therapeutic outcomes of HIFU-mediated thermal ablation treatments.

Phase-shift nanoemulsions (PSNE) can be vaporized using high intensity focused ultrasound to enhance localized heating and improve thermal ablation in tumors. In this report, the preparation of stable PSNE with a narrow size distribution is described. Furthermore, the impact of vaporized PSNE on ultrasound-mediated ablation is demonstrated in tissue-mimicking phantoms.

High-intensity  focused ultrasound (HIFU) is used clinically to thermally ablate tumors. To  enhance localized heating and improve thermal ablation in ...

Characterization of Anisotropic Leaky Mode Modulators for Holovideo

Holovideo displays are based on light-bending spatial light modulators. One such spatial light modulator is the anisotropic leaky mode modulator. This modulator is particularly well suited for holographic video experimentation as it is relatively simple and inexpensive to fabricate1-3. Some additional advantages of leaky mode devices include: large aggregate bandwidth, polarization separation of signal light from noise, large angular deflection and frequency control of color1. In order to realize these advantages, it is necessary to be able to adequately characterize these devices as their operation is strongly dependent on waveguide and transducer parameters4. To characterize the modulators, the authors use a commercial prism coupler as well as a custom characterization apparatus to identify guided modes, calculate waveguide thickness and finally to map the device's frequency input and angular output of leaky mode modulators. This work gives a detailed description of the measurement and characterization of leaky mode modulators suitable for full-color holographic video.

This work describes fabrication and characterization of anisotropic leaky mode modulators for holographic video.

Holovideo displays are based on light-bending spatial light modulators.  One such spatial light modulator is the anisotropic leaky mode modulator.  This ...

The Evolution of Silica Nanoparticle-polyester Coatings on Surfaces Exposed to Sunlight

Corrosion of metallic surfaces is prevalent in the environment and is of great concern in many areas, including the military, transport, aviation, building and food industries, amongst others. Polyester and coatings containing both polyester and silica nanoparticles (SiO2NPs) have been widely used to protect steel substrata from corrosion. In this study, we utilized X-ray photoelectron spectroscopy, attenuated total reflection infrared micro-spectroscopy, water contact angle measurements, optical profiling and atomic force microscopy to provide an insight into how exposure to sunlight can cause changes in the micro- and nanoscale integrity of the coatings. No significant change in surface micro-topography was detected using optical profilometry, however, statistically significant nanoscale changes to the surface were detected using atomic force microscopy. Analysis of the X-ray photoelectron spectroscopy and attenuated total reflection infrared micro-spectroscopy data revealed that degradation of the ester groups had occurred through exposure to ultraviolet light to form COO&#903;, -H2C&#903;, -O&#903;, -CO&#903; radicals. During the degradation process, CO and CO2 were also produced.

Two types of surfaces, polyester-coated steel and polyester coated with a layer of silica nanoparticles, were studied. Both surfaces were exposed to sunlight, which was found to cause substantial changes in the chemistry and nanoscale topography of the surface.

Corrosion of metallic surfaces is prevalent in the environment and is of great concern in many areas, including the military, transport, aviation, ...

A Robotic Platform to Study the Foreflipper of the California Sea Lion

The California sea lion (Zalophus californianus), is an agile and powerful swimmer. Unlike many successful swimmers (dolphins, tuna), they generate most of their thrust with their large foreflippers. This protocol describes a robotic platform designed to study the hydrodynamic performance of the swimming California sea lion (Zalophus californianus). The robot is a model of the animal&#39;s foreflipper that is actuated by motors to replicate the motion of its propulsive stroke (the &#39;clap&#39;). The kinematics of the sea lion&#39;s propulsive stroke are extracted from video data of unmarked, non-research sea lions at the Smithsonian Zoological Park (SNZ). Those data form the basis of the actuation motion of the robotic flipper presented here. The geometry of the robotic flipper is based a on high-resolution laser scan of a foreflipper of an adult female sea lion, scaled to about 60% of the full-scale flipper. The articulated model has three joints, mimicking the elbow, wrist and knuckle joint of the sea lion foreflipper. The robotic platform matches dynamics properties&#8212;Reynolds number and tip speed&#8212;of the animal when accelerating from rest. The robotic flipper can be used to determine the performance (forces and torques) and resulting flowfields.

A robotic platform is described that will be used to study the hydrodynamic performance&#8212;forces and flowfields&#8212;of the swimming California sea lion. The robot is a model of the animal&#39;s foreflipper that is actuated by motors to replicate the motion of its propulsive stroke (the &#39;clap&#39;).

The California sea lion (Zalophus californianus), is an agile and powerful swimmer. Unlike many successful swimmers (dolphins, tuna), they generate most ...

Ice Generation and the Heat and Mass Transfer Phenomena of Introducing Water to a Cold Bath of Brine

We demonstrate a method for the study of the heat and mass transfer and of the freezing phenomena in a subcooled brine environment. Our experiment showed that, under the proper conditions, ice can be produced when water is introduced to a bath of cold brine. To make ice form, in addition to having the brine and water mix, the rate of heat transfer must bypass that of mass transfer. When water is introduced in the form of tiny droplets to the brine surface, the mode of heat and mass transfer is by diffusion. The buoyancy stops water from mixing with the brine underneath, but as the ice grows thicker, it slows down the rate of heat transfer, making ice more difficult to grow as a result. When water is introduced inside the brine in the form of a flow, a number of factors are found to influence how much ice can form. Brine temperature and concentration, which are the driving forces of heat and mass transfer, respectively, can affect the water-to-ice conversion ratio; lower bath temperatures and brine concentrations encourage more ice to form. The flow rheology, which can directly affect both the heat and mass transfer coefficients, is also a key factor. In addition, the flow rheology changes the area of contact of the flow with the bulk fluid.

Here, we present a protocol to demonstrate the generation of ice when water is introduced to a cold bath of brine, as a secondary refrigerant, at a range of temperatures well below the freezing point of water. It can be used as an alternative way of producing ice for industry.

We demonstrate a method for the study of the heat and mass transfer and of the freezing phenomena in a subcooled brine environment. Our experiment showed ...

Preparation and High-temperature Anti-adhesion Behavior of a Slippery Surface on Stainless Steel

Anti-adhesion surfaces with high-temperature resistance have a wide application potential in electrosurgical instruments, engines, and pipelines. A typical anti-wetting superhydrophobic surface easily fails when exposed to a high-temperature liquid. Recently, Nepenthes-inspired slippery surfaces demonstrated a new way to solve the adhesion problem. A lubricant layer on the slippery surface can act as a barrier between the repelled materials and the surface structure. However, the slippery surfaces in previous studies rarely showed high-temperature resistance. Here, we describe a protocol for the preparation of slippery surfaces with high-temperature resistance. A photolithography-assisted method was used to fabricate pillar structures on stainless steel. By functionalizing the surface with saline, a slippery surface was prepared by adding silicone oil. The prepared slippery surface maintained the anti-wetting property for water, even when the surface was heated to 300 &#176;C. Also, the slippery surface exhibited great anti-adhesion effects on soft tissues at high temperatures. This type of slippery surface on stainless steel has applications in medical devices, mechanical equipment, etc.

Slippery surfaces provide a new way to solve the adhesion problem. This protocol describes how to fabricate slippery surfaces at high temperatures. The results demonstrate that the slippery surfaces showed anti-wetting for liquids and a remarkable anti-adhesion effect on soft tissues at high temperatures.

Anti-adhesion surfaces with high-temperature resistance have a wide application potential in electrosurgical instruments, engines, and pipelines. A ...

Scalable Solution-processed Fabrication Strategy for High-performance, Flexible, Transparent Electrodes with Embedded Metal Mesh

Here, the authors report the embedded metal-mesh transparent electrode (EMTE), a new transparent electrode (TE) with a metal mesh completely embedded in a polymer film. This paper also presents a low-cost, vacuum-free fabrication method for this novel TE; the approach combines lithography, electroplating, and imprint transfer (LEIT) processing. The embedded nature of the EMTEs offers many advantages, such as high surface smoothness, which is essential for organic electronic device production; superior mechanical stability during bending; favorable resistance to chemicals and moisture; and strong adhesion with plastic film. LEIT fabrication features an electroplating process for vacuum-free metal deposition and is favorable for industrial mass production. Furthermore, LEIT allows for the fabrication of metal mesh with a high aspect ratio (i.e., thickness to linewidth), significantly enhancing its electrical conductance without adversely losing optical transmittance. We demonstrate several prototypes of flexible EMTEs, with sheet resistances lower than 1 &#937;/sq and transmittances greater than 90%, resulting in very high figures of merit (FoM) &#8211; up to 1.5 x 104 &#8211; which are amongst the best values in the published literature.

This protocol describes a solution-based fabrication strategy for high-performance, flexible, transparent electrodes with fully-embedded, thick metal mesh. Flexible transparent electrodes fabricated by this process demonstrate among the highest reported performances, including ultra-low sheet resistance, high optical transmittance, mechanical stability under bending, strong substrate adhesion, surface smoothness, and environmental stability.

Here, the authors report the embedded metal-mesh transparent electrode (EMTE), a new transparent electrode (TE) with a metal mesh completely embedded in a ...

Preparation of Aligned Steel Fiber Reinforced Cementitious Composite and Its Flexural Behavior

The aim of this work is to present an approach, inspired by the way in which a compass needle maintains a consistent orientation under the action of the Earth&#39;s magnetic field, for manufacturing a cementitious composite reinforced with aligned steel fibers. Aligned steel fiber reinforced cementitious composites (ASFRC) were prepared by applying a uniform electromagnetic field to fresh mortar containing short steel fibers, whereby the short steel fibers were driven to rotate in alignment with the magnetic field. The degree of alignment of steel fibers in hardened ASFRC was assessed both by counting steel fibers in fractured cross-sections and by X-ray computed tomography analysis. The results from the two methods show that the steel fibers in ASFRC were highly aligned while the steel fibers in non-magnetically treated composites were randomly distributed. The aligned steel fibers had a much higher reinforcing efficiency, and the composites, therefore, exhibited significantly enhanced flexural strength and toughness. The ASFRC is thus superior to SFRC in that it can withstand greater tensile stress and more effectively resist cracking.

This protocol describes an approach for manufacturing aligned steel fiber reinforced cementitious composite by applying a uniform electromagnetic field. Aligned steel fiber reinforced cementitious composite exhibits superior mechanical properties to ordinary fiber reinforced concrete.

The aim of this work is to present an approach, inspired by the way in which a compass needle maintains a consistent orientation under the action of the ...

Scalable Stamp Printing and Fabrication of Hemiwicking Surfaces

Hemiwicking is a process where a fluid wets a patterned surface beyond its normal wetting length due to a combination of capillary action and imbibition. This wetting phenomenon is important in many technical fields ranging from physiology to aerospace engineering. Currently, several different techniques exist for fabricating hemiwicking structures. These conventional methods, however, are often time consuming and are difficult to scale-up for large areas or are difficult to customize for specific, nonhomogeneous patterning geometries. The presented protocol provides researchers with a simple, scalable, and cost-effective method for fabricating micro-patterned hemiwicking surfaces. The method fabricates wicking structures through the use of stamp printing, polydimethylsiloxane (PDMS) molding, and thin-film surface coatings. The protocol is demonstrated for hemiwicking with ethanol on PDMS micropillar arrays coated with a 70 nm thick aluminum thin-film.

A simple protocol is provided for the fabrication of hemiwicking structures of varying sizes, shapes, and materials. The protocol uses a combination of physical stamping, PDMS molding, and thin-film surface modifications via common materials deposition techniques.

Hemiwicking is a process where a fluid wets a patterned surface beyond its normal wetting length due to a combination of capillary action and imbibition. ...

Generating Lap Joints Via Friction Stir Spot Welding on DP780 Steel

Friction stir spot welding (FSSW), a derivative of friction stir welding (FSW), is a solid-state welding technique that was developed in 1991. An industry application was found in the automotive industry in 2003 for the aluminum alloy that was used in the rear doors of automobiles. Friction stir spot welding is mostly used in Al alloys to create lap joints. The benefits of friction stir spot welding include a nearly 80% melting temperature that lowers the thermal deformation welds without splashing compared to resistance spot welding. Friction stir spot welding includes 3 steps: plunging, stirring, and retraction. In the present study, other materials including high strength steel are also used in the friction stir welding method to create joints. DP780, whose traditional welding process involves the use of resistance spot welding, is one of several high strength steel materials used in the automotive industry. In this paper, DP780 was used for friction stir spot welding, and its microstructure and microhardness were measured. The microstructure data showed that there was a fusion zone with fine grain and a heat effect zone with island martensite. The microhardness results indicated that the center zone exhibited a greater degree of hardness compared with the base metal. All data indicated that the friction stir spot welding used in dual phase steel 780 can create a good lap joint. In the future, friction stir spot welding can be used in high-strength steel welding applied in industrial manufacturing processes.

Here, we present a friction stir spot welding (FSSW) protocol on dual phase 780 steel. A tool pin with high-speed rotation generates heat from friction to soften the material, and then, the pin plunges into 2 sheet joints to create the lap joint.

Friction stir spot welding (FSSW), a derivative of friction stir welding (FSW), is a solid-state welding technique that was developed in 1991. An industry ...