An Effective Method Of Sand Control

Abstract

Abstract Lab and field data show that a new, uncured resin-coated sand is highly effective in sand-control applications. Called Super Sand or Super Gravel, the material is ideal for gravel packing, linerless gravel packs, and as a high-strength, consolidating fracture packs, and as a high-strength, consolidating fracture proppant. The coated sand or gravel comes ready to proppant. The coated sand or gravel comes ready to use as a free-flowing dry additive. No chemicals or flushes that complicate field procedures are required. The thin resin coating on the sand thermosets at formation temperatures in the wellbore or in the formation, to form a very permeable, strong, consolidated mass. After thermosetting, Super Sand is inert to most chemicals and additives. This paper discusses the unique properties of Super Sand, its applications, and available data on field testing. Introduction Gross sand production and formation fines migration seriously interfere with oil and gas production. Sand and fines movement is caused primarily by increased pressure drawdown or stress. Sand grains and fines are moved by fluid frictional forces, crushed by compaction, and loosened by water invasion. Any migration is detrimental to production from wells, and workover treatments may be required to restore it. Sand control is often associated with the Miocene formations in which the sands are poorly consolidated, but quite prolific. Other problems requiring sand control involve deeper wells that make enough water to dissolve the grain-cementation materials and wells with excessive drawdown, such as single-well reservoirs? In the future, large amounts of hot water and gas may be produced from relatively deep, well-consolidated sands; in these geopressured wells, sand-control measures may be vital. When particle migration occurs in a producing well, the noticeable effects are either a fall-off in production or the production of sand along with the production or the production of sand along with the oil or gas. Small particles move toward the wellbore as a result of fluid movement and pressure gradient. Eventually, these particles will be produced, plug a flow channel, or filter out on a liner or screen. The need to control fine sand or formation material has been recognized for over 50 years in the oilfield. In the 1920s, liners made from slotted pipe or wire-wrapped screen were used quite effectively in openhole completions. In the late thirties, however, when gun perforating became widely used, screens began to fall early due to the sand-blasting effect of production through the perforations (Figure 1). To solve production through the perforations (Figure 1). To solve this and other problems associated with sand production, many materials have been used and tested. The production, many materials have been used and tested. The materials include sintered stainless steel and brass, carborundum, aloxite, glass marbles, ceremic filters, and prepacked gravel liners! The prepacked gravel liner was the only method that worked very well. The prepacked gravel was cohesive and did not allow sand prepacked gravel was cohesive and did not allow sand or gravel movement. In many areas, this solved the primary problem (sand production) and the secondary primary problem (sand production) and the secondary problem (screen failure). In other areas, however, problem (screen failure). In other areas, however, gravels became fluidized and move during production. As a result, the screen is not protected and fails early (Figure 1). We still need cohesive gravel for longer-lasting screens and gravel packs. A second widely used method of sand control is in-situ consolidation of the formation sand and its fines. This concept was introduced around 1946. Much work and research has gone into the development and improvement of the in-situ techniques. Basically, in-situ consolidation involves the injection of a plastic or epoxy which coats the sand and hardens to plastic or epoxy which coats the sand and hardens to form an artificial cement between the sand grains. The most effective use of the wet-type processes of in-situ consolidation is for short sections (20 feet or less) of relatively clean formation sands. The way that available processes work is shown schematically in Figure 2. While often effective, some processes have problems with catalyst addition, resin dilution, lack of an effective coupling agent, pore plugging, and preflushes and afterflushes. One or more of these factors can cause trouble or just result in a more-complicated or more-expensive field operation. A need is seen for a simpler treatment that is effective.