TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractIn recent years, expandable sand screen (ESS) has become popular as a sand exclusion mechanism in oil and gas sand face completion. ESS provides sand control through the bridging of formation sand on the screen that is sized to retain formation sand while allowing formation fines to pass through. The deployment of Cased Hole ESS (CHESS) in The Shell Petroleum Development Company of Nigeria Ltd (SPDC) since the late 90's has been mainly as a remedial sand control mechanism post-workover operation to replace the previous sand control mechanism if any or to complete over a new interval. The successful deployment of CHESS in over 30 conduits in the Niger Delta by SPDC over the years has come with various challenges and lessons learned leading to improvements in the selection criteria, deployment methodology and procedure, clean-up and operational envelope of usage. This paper presents some of the results and the lessons learned in CHESS deployment in SPDC and offers an insight into the selection and usage of CHESS as a sand control mechanism especially in well remedial operations to prolong well life and optimise hydrocarbon recovery.

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FEDA field is a medium-sized, step faulted anticline located in the coastal swamp area of the Niger Delta. The field is located about 70km south-west of Port Harcourt, Nigeria and has produced approximately 126MMstb of oil and 127Bscf of associated gas. The field has been developed with 9 wells (18 strings) with one well abandoned. Production from the wells is maintained by natural flow supported by a strong aquifer drive. The field was shut down for about 5years between 2008 and 2013 due to integrity issues with the trunk line. As at 2008 before the field was shut down, it produced 4.8Mbopd from 3 wells (5 strings). In 2010, a new trunk-line was commissioned which led to the re-opening of all the fields in the Swamp area including FEDA. However, there were various challenges that needed to be addressed before the flow station could be re-opened. One of such issues was the availability of gas to run the Low-Pressure, (LP) compressor, given its turn-down volume and due to restriction placed by the new flares-down policy being championed by SPDC. In order to solve this problem, an Integration Production System Model (IPSM) was constructed. The model was calibrated ensuring accurate split between low pressure and high pressure gas streams which is not often considered in conventional IPSM analysis. The second issue was to consider the best scenario that would lead to optimum net oil production with the least volume of flared gas during compressor downtime in order to minimize production deferment. The key outcome of the project is that accurate calibration of IPSM model can unlock asset deliverables and guide operations towards optimum oil production. This paper presents the results of an innovative use of the PETEX IPM to determine the accurate volume of low-pressure gas for re-start of an oil flow station in Niger Delta. The objective was to ensure that produced gas was not flared and that the volume of associated gas would be sufficient to operate the compression facility efficiently.

Horizontal drilling technology is a fairly mature technology. Advances in drilling tools and techniques have simplified the technology making it a common concept in field development projects both in green and brown fields. The objective of sandface completion in horizontal wells is to prevent collapse of the horizontal drainhole (borehole support and/or prevent sand production. The first objective applies to where the formation is relatively consolidated and therefore does not require sand-control. The second objective applies to friable formations with propensity for sand production. Various sandface completion mechanisms have been deployed in SPDC horizontal wells. These include pre-drilled liners, slotted liners, openhole expandable sand screens, stand-alone screens and a combo of stand-alone screen, swellable packers and interval control devices (ICDs). With nearly 150 horizontal wells (including sidetracks and muti-laterals) drilledbetween 1992 and 2012, there has been a significant improvement in sandface completion philosophy mainly driven by the desire to achieve life-cycle sand exclusion. The earlier wells were completed with slotted liners while later applications have deployed stand-alone screens. Performance of these wells is constantly being reviewed for further optimization of the sandface completions where scope exists. This paper traces the development of horizontal sandface completion in SPDC from the early days to present highlighting factors that led to improvements. It also explores the current trend in horizontal sandface completion, limitation of existing technology and scope for improvement.

Intelligent well technology use Inflow Control Devices (ICDs), Inflow Control Valves (ICVs), and measurement devices that provide opportunity for monitoring and control of production from different reservoirs from the same wellbore. The common value drivers for the deployment of intelligent wells include reduction in well count during field development; accelerated ultimate recovery (UR); and accelerated production. Efficient and accurate modelling is therefore critical for the realisation of the full benefits of intelligent wells in addition to other technologies like the use of geochemical finger printing. In this paper, a simple workflow for modelling the performance of intelligent wells is presented. This workflow identifies the limitation of current standalone PROSPER model and provides a window to easily match the model to actual well test results, providing multiple calibration points and ensuring full utilisation of the data made available by the intelligent well accessories like the permanent downhole guage and downhole flowmeter. The workflow has been applied to carryout nodal analysis of both oil and gas completions in the Niger Delta, Nigeria. The modelling workflow is divided into two (2) aspects – the inflow modeling, for each inflow zone, and the outflow modelling that captures the commingled production. The commngled outflow model is used to generate the lift table for the GAP model. The well deliverability and PQ curves are generated and plotted using the Openserver utility in IPM, which can be used also to view the performance of the model against validated well test results. Results of applying the workflow to two case studies in the Niger Delta were analysed. The model was used to predict the expected performance of the wells at different surface choke sizes and ICV settings. The model results (flow rate, flowing tubing head pressures, flowing bottomhole pressures) matched closely (with maximum of 10% deviation) with the actual measured results, confirming the accuracy of the recommended workflow.