Completion Techniques Used in Horizontal Wells Drilled in Shallow Gas Sands in the Gulf of Mexico

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SPE Members Abstract Texaco has completed three horizontal wells in shallow gas sands in the Gulf of Mexico. The producing sands in all these wells have relatively high permeabilities and are unconsolidated. This paper discusses the process used to select the completion hardware, drilling fluids, and completion fluids for these wells. In addition, the completion procedure will be discussed in some detail to illustrate the most significant aspects of the completion process. Finally, production histories of the three wells will be presented to highlight the efficiency of the completion system used in these wells. Introduction In the Gulf of Mexico, Texaco has drilled and completed three horizontal gas wells in shallow unconsolidated sands. Two of the wells are located in the East Cameron 278 block and one in the Eugene Island 367 block. The producing intervals of the three wells range from 1700 to 1900 ft TVD. These sands have relatively high permeabilities and are unconsolidated. For these reasons, planning the completion of these horizontal wells required provisions for sand control and minimizing formation damage during the drilling operation and completion phase. All three wells were long radius horizontal wells with 9 5/8-in intermediate casing set at the top of the sand. The horizontal section was then drilled to total depth with a 8 1/2-in bit and completed with a combination of a 5-in prepacked liner inside a 7-in liner. However, before the wells were actually drilled and completed, ft was necessary to select the best suited completion assembly, completion fluid and drilling fluid. MECHANICAL COMPLETION SELECTION There is a variety of mechanical assemblies available for completing horizontal wells in unconsolidated high permeability reservoirs. Accordingly, the cost and risk associated with each of these options varies significantly. The most common mechanical completions include:Fully cemented liner, perforated and gravel packed.Open hole completion with a prepacked liner and gravel packed.Open hole completion with a prepacked liner orprepacked screen.Open hole completion with slotted liner and prepacked liner inside. It should be noted that the slotted liners, prepacked liners and prepacked screens can be used in conjunction with external packers if zone isolation is desired. P. 797^