Gravel pack

Well completions are usually tailored to individual wells, and many variations exist. The following diagrams show a completion with a gravel pack, designed to exclude sand production downhole, and a dual completion, designed to allow controlled production from two separate reservoirs. 

Figure 9.15 Gravel pack completion and dual completion...

In the internal gravel pack shown, carefully sorted sand grains, called gravel, are placed between a wire wrapped screen and the perforations with the objective of stopping... 

The bare foot completion, which leaves an open hole section below the previous casing, is cheap, simple and suitable for consolidated formations which have little tendency to collapse. The slotted liner s an uncemented section of casing with small intermittent slots cut along its length, which prevents the hole from collapsing, but allows no selectivity of the interval which will be produced. The cased and cemented horizontal completion does allow a choice of which intervals will be perforated and produced. None of these examples provides any effective sand exclusion it this is required a gravel pack or a pre-packed liner can be used. 

GRAVEL-PACKED GAS WELL vented TO THE atmosphere OR BURNED IN GAS BURNER... 

MAIN LEACHATE COLLECTION LINE, USE OF PERFORATED LATERALS will depend on topography AND EXTENT OF LANDFILL. MAINLINE AND LATERALS SHOULD BE GRAVEL-PACKED. 

Screened or screened and gravel-packed in incompetent sands and gravels... 

T. E. Hudson and J. W. Martin. Pyrolytic carbon coating of media improves gravel packing and fracturing capabilities. Patent EP 301626, 1989. 

FORMATION SAND AND GRAVEL PACK MATERIAL MIGHT CREATE AN EXTRA SKIN... 

MIGRATION OF FINES DURING PRODUCTION MIGHT CREATE BRIDGING OR PERMANENT DAMAGES OF THE GRAVEL PACK... 

Gravel pack. Gravel pack and perforated completions are used where unconsolidated sands in the injection zone must be supported. In gravel-pack completions the cavity in the injection zone is filled with gravel or, more typically, a screen or liner is placed in the injection-zone cavity before the cavity is filled with gravel. In perforated completions, the casing and cement extend into the injection zone and are then perforated in the most permeable sections. In 1985, 53% of Class I wells were perforated and 17% were screened.20... 

Use gravel-pack well screen. Inject a slug of brine after every period of interrupted flow. 

Another method of sand control is use of a silicon halide which reacts with water at the surface of sand grains forms SiO which can bond the grains together (55). Reducing the cost of sand consolidation could be very useful since the applicability of gravel packing methods is limited by the bottom hole circulating temperature and the limited temperature stability of polysaccharide polymers. 

Acid washing is used to dissolve acid-soluble scales from the well bore and to open gravel packs and perforations plugged by such scales. 

Torrest, R.S. "Aspects of Slurry and Particle Settling and Placement for Viscous Gravel Packing (AQUAPAC)," SPE paper 11009, 1982 Annual Fall Technical Conference and Exhibition of the SPE of AIME, New Orleans, September 26 29. 

Potential problems can result if monitoring well construction is such that the gravel pack and screened interval are not discretely terminated at the confining layer and its grouted annulus. 

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