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A case history from Offshore Israel is presented that describes the successful delivery of two ultra high-rate gas wells (>200 MMscf/D) completed in a depleted gas reservoir with 9⅝-in. production tubing and an openhole gravel pack (OHGP). Maximizing gas off-take rates from a volumetric drive gas reservoir that possesses high flow capacity (kh) requires large internal diameter (ID) tubing coupled with efficient sand face completions. When sand control is required, the OHGP offers the most efficient as well as the most reliable, long-term track record of performance. A global study of wells completed with 9⅝-in. production tubing ("big bore") determined that this design concept was feasible and deliverable in a short time frame while still maintaining engineering rigor. The paper will highlight key accomplishments within various phases of a completion delivery process with particular emphasis on the sand control design, testing and execution. The completions were installed with minimal issues (NPT ≈ 9%) and have produced without incident. The two wells, Mari-B #9 and #10, achieved a peak gas rate of 223 and 246 MMscf/D, respectively.

A set of Continuously Operating Reference Stations (CORS) distributed all over Nigeria constitutes the Nigerian GNSS Reference Network referred to  as NIGNET. Global Navigation Satellite System (GNSS) is a system tha  uses satellites for autonomous position determination, and is a critical  component of the modern-day geodetic infrastructure and services. Using CORS provide geodetic controls of comparable accuracy and a better alternative to the classical geodetic network. As the NIGNET infrastructure is utilised for different geodetic applications, it has become necessary to evaluate the suitability of the network data for the definition of a geodetic reference frame (GRF). This study utilised the technique of Precise Point Positioning (PPP) in position estimation, and time series analysis for temporal monitoring of the network. The sufficiency and adequacy of the NIGNET data archive was also evaluated against that of an International GNSS Service (IGS) Station. The temporal stability of the station coordinates measured in terms of standard deviations varied between 10 mm and 22 mm. This analysis suggests a relative stability required for Tiers 1 and 2 CORS in line with the IGS standards. Based on this reported stability, it is concluded that NIGNET is fit for purpose in defining the Nigerian Geodetic Reference Frame. However, despite the good data quality observed, the adequacy of the network has been compromised by infrastructural failures and lack of continuity in data transmission. Accordingly, it is recommended that both practical and policy measures required to ensure the  realisation of the goal of the network should be implemented. Keywords: Geodetic reference frame, NIGNET, CORS, precise point positioning, temporal stability and adequacy.

An operator was planning to drill the first horizontal well in the Inhassoro field in Mozambique. The type of completion would be an open hole utilizing expandable screen technology. The formation had highly reactive shale stringers necessitating the use of an inhibitive fluid, but due to the environmental restrictions, the use of non-aqueous fluid systems could not be used to drill or complete the horizontal section. The issue of cleaning up the filter cake was examined as it would be confined with the use of the expandable screen. Normally a breaker system would be required to cleanup or disperse the filter cake with this type of completion; but due to the water sensitivity of the reservoir, any aqueous filtercake breaker would have to be left out of the completion process.The reservoir drill-in system used to drill horizontal section would require an inhibitive water-based fluid that was also chloride free due to possible contact with the ground water. The system would also require a filter cake that could be cleaned up with the producing hydrocarbons due to the absence of any filtercake breaker system. The filter cake must also demonstrate a low permeability in order to limit the invasion of fluid into the sensitive formation. A low coefficient of friction would also be another requirement for the reservoir drill-in system. This paper will highlight the design optimization, the unique characteristic, the testing and the successful implementation of this special reservoir drill-in system.

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