TX 75083-3836 U.S.A., fax 01-972-952-9435.
AbstractThe alternate steam injection consist in force the reservoir to a cyclic sequence of heating and cooling process injecting hot water steam (500°-600° F) in order to improve the mobility for the extra-heavy crude in the reservoir, this is a very common practice for secondary recovery on the Tía Juana and Lagunillas fields, located in the eastern side of the Maracaibo Lake.A destructive collapse failure on the production tubing was observed over the last wells exposed to this injection process. The investigation of the failure includes field visits, laboratory tests, and the computer simulations.The study was prepared using a computer program able to create the different temperature profiles for the different scenarios and link them with the simulations for load cases, the results demonstrate the deterioration effect of temperature on the mechanical properties of the tubing, with particular interest on the expansion of the fluid trapped between the casing and the injection tubing, leading the collapse failure (AFE Analysis).The analysis of the production tubing movement and buckling due to the thermal effect, ballooning and Hook´s law is also included.
TX 75083-3836 U.S.A., fax 01-972-952-9435.
AbstractThis paper describes the field evaluation of drilling strings with different stabilizing configurations, so that minimizes bit vibration problems in the bottomhole assemblies (BHA), contributing to optimize the performance. The studio was made for Lagotreco field, Block III in Maracaibo Lake. The evaluation is supported with simulation results obtained with drilling computer applications.The use of BHA designs with the criteria of stabilization "30-60ft" (stabilizers placed to 30ft and 60ft from bit, respectively), generally used in western PDVSA operational areas, to control straight holes and displacements; cause premature damages at the bits, such as broken cutters, chipped cutters, lost cutters and ring outs. These dull characteristics are potential signs of lateral vibration, increasing drilling costs because of additional bit trips.A dynamic analysis study of three different stabilizing configurations for BHA (30 -60ft, 15-45ft and 0-30ft), show the values rank for critical rpm speed, side forces and displacements measured from bit, for every case.The field test evaluation shows the reduction of bit damages by vibration effects, with a BHA stabilized 15'-45'; so that the decreasing of drilling time in terms of costs per feet (CPF). The study also includes an unconfined compressive strength formation analysis from the study area (USC).
Temperature fall-off logs are routinely performed on a number of operating wells at Statoil's Leismer field to monitor well integrity. So far, all wells have demonstrated normal temperatures in formations overlying the steam chamber, less than steam temperatures, and with fall-offs according to typical heat conduction. However, one injector well did not fall-off as expected after a 24 hour shut-in; instead showed temperatures exceeding 200°C in formations above the steam chamber. An investigation was launched and a multidisciplinary team evaluated possible causes for the high temperatures.
A review of 4D seismic data showed that a neighbouring steam chamber was intersecting the wellbore. This led to the hypothesis that the high temperatures were the result of wellbore heating from the neighbouring steam chamber, and a follow-up, extended temperature fall-off log confirmed the hypothesis. The extended logging period confirmed that temperatures outside casing did fall-off, albeit at a slower rate than other wells, due to the heating effect of the neighbouring steam chamber. The temperature log measurements indicate that heat from an intersecting steam chamber can cause a counter-intuitive segregation of steam and water in the wellbore, with condensed liquid water held above steam in the upper section of the well. This case study highlights strategies for interpreting downhole temperature anomalies using temperature logs and 4D seismic, and also the benefits of a well integrity investigation with strong cross-discipline collaboration.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.