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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractQT-16Cr chrome coiled tubing was introduced in 2003, but its use has been limited to velocity strings in corrosive environments. Questions concerning its feasibility as a workstring prompted field testing of a reel of QT-16Cr on the North Slope, Alaska.Following preliminary laboratory testing, a QT-16Cr reel was deployed in the field and performed a variety of standard coil tubing applications on a daily basis for a three-month field trial. Observations and data were gathered during the field testing to determine operating guidelines, applicability, and limitations of this new coiled tubing technology. The successful field trial indicated QT-16Cr has increased low cycle fatigue life, superior abrasion resistance in chrome completions, and higher resistance to damage in corrosive environments in comparison to standard HS-80 coiled tubing. This paper documents the testing and results of the lab and field studies. In addition, standard operating procedures for QT-16Cr are described and provide easily implemented guidelines which should work in virtually any area coiled tubing operations are performed. This paper is significant for worldwide coiled tubing operations, especially in areas with high rates of coiled tubing corrosion and where coiled tubing wear is significant due to abrasive tubing tubulars.

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractQT-16Cr chrome coiled tubing was introduced in 2003, but its use has been limited to velocity strings in corrosive environments. Questions concerning its feasibility as a workstring prompted field testing of a reel of QT-16Cr on the North Slope, Alaska.Following preliminary laboratory testing, a QT-16Cr reel was deployed in the field and performed a variety of standard coil tubing applications on a daily basis for a three-month field trial. Observations and data were gathered during the field testing to determine operating guidelines, applicability, and limitations of this new coiled tubing technology. The successful field trial indicated QT-16Cr has increased low cycle fatigue life, superior abrasion resistance in chrome completions, and higher resistance to damage in corrosive environments in comparison to standard HS-80 coiled tubing. This paper documents the testing and results of the lab and field studies. In addition, standard operating procedures for QT-16Cr are described and provide easily implemented guidelines which should work in virtually any area coiled tubing operations are performed. This paper is significant for worldwide coiled tubing operations, especially in areas with high rates of coiled tubing corrosion and where coiled tubing wear is significant due to abrasive tubing tubulars.

Background: Fontan failure patients with diastolic dysfunction with elevated systemic venous pressures, and systolic dysfunction with elevated ventricular end-diastolic pressures, are at a high risk of morbidity. These patients will require cavopulmonary support that replaces the subpulmonary power source to treat diastolic dysfunction and a left ventricular assist device (LVAD) to unload the native ventricle to treat systolic dysfunction. A physiologic control algorithm is needed to autonomously maintain systemic and pulmonary circulation balance at different clinical conditions. Methods: Mathematical models of a cavopulmonary assist device (CPAD) was developed from mock circulation data. CPAD and LVAD models were coupled to the Fontan failure circulatory system model. Proportional integral (PI) controllers were used to maintain a constant cavopulmonary pressure head (CPPH) of 5-8 mmHg for the CPAD and 75-80 mmHg for the pump pressure head across the LVAD. The control algorithm was tested for rest, exercise, transitions from rest to exercise, and rapid increases in systemic vascular (SVR) and pulmonary vascular resistances (PVR). Results and conclusions:The control algorithm maintained adequate perfusion by autonomously adjusting the pump speed during rest and exercise conditions. Steady state ventricular end diastolic pressures were <10 mmHg indicating adequate systemic unloading of the native ventricle even with CPAD support. Vena caval and ventricular suction were not observed during transitions from exercise to rest and rapid increases in SVR and PVR. These results demonstrate the feasibility of a physiologic control algorithm to maintain systemic and pulmonary circulation balance in failing Fontan patients.

fax 01-972-952-9435. AbstractSixteen chrome coiled tubing (16Cr CT) was introduced in the spring of 2003 and over 200 strings have been put into field use as velocity strings. Following preliminary testing, two 16Cr CT reels were deployed at Prudhoe Bay, Alaska to evaluate feasibility as an intervention workstring. The two reels performed a variety of standard CT applications on a daily basis. Observations and data were gathered to determine operating guidelines, applicability, and limitations. The field trial indicated that 16Cr CT can be deployed in the field with only minor operational modifications.16Cr has superior abrasion resistance in 13Cr production tubulars and little CT surface (external) wear was seen during the field trial. The second reel developed a pinhole failure earlier than expected; however, analysis of the adjacent material indicates that 16Cr has increased low cycle fatigue life when compared to standard carbon steel CT. Additional testing is ongoing, and it is felt that the conditions resulting in the failure can be mitigated to avoid future premature failure. This paper documents the lab and field trial results. Standard operating procedures for 16Cr CT are described that provide easily implemented guidelines. 16Cr has applicability as an intervention workstring, particularly in corrosive environments and in areas where abrasive 13Cr production tubulars must be endured.Recognition is extended to the BP Alaska Wells Team who contributed to making the 16Cr CT field trial a success. Special recognition is made to