Ultralightweight Proppants: An Effective Approach To Address Problems in Long Horizontal Gravel Packs Offshore Brazil

Abstract

Operators developing reservoirs and producing them from deep and ultradeepwater wells are pushing the technical limits regarding horizontal extension. Deepwater wells completed in unconsolidated formations usually have low fracture gradients, severe leakoff zones, and/or significant washouts. Long horizontal open holes, therefore, may become technically difficult or economically unfeasible to gravel-pack with the use of conventional fluids and gravels.Typical completions in offshore Brazil start from a 9 5 =8or 10 3 =4-in. casing, in which a 5 1 =2-in. premium screen and tubular string is hung along an open hole drilled with an 8 1 =2or 9 1 =2-in. bit. Horizontal extensions range from 980 to 4,000 ft. A variety of openhole gravel-pack techniques proved to be complex and costly, but ultralightweight (ULW) proppants have enabled simpler and more-cost-effective gravel packing in these longer horizontal open holes. The reduced gravel density allows a significant reduction in pumping rate that avoids fracturing the formation, minimizes fluid loss, and eliminates the risk of premature screenout caused by excessive gravel settling.ULW-proppant technology was introduced to Brazil in 2005 and has been applied successfully to gravel pack wells under extreme conditions such as low fracture gradient, severe fluid loss, and washed-out zones. ProppantULW-1.25 has proved to be effective for packing wells with narrow sections through the openhole interval, frequently found in horizontal wells completed through shale zones that are isolated by reactive packers and/or mechanical external casing packers. ULW-1.75 was introduced in Brazil in 2007 and has largely replaced ULW-1.25 for gravel packing wells in which an improvement in the operational pumping window is required. A combined package comprising ULW-1.75 during the alpha-wave phase and ULW-1.25 during the beta-wave phase is also discussed. This paper summarizes the procedures and results of almost 60 wells that have been gravel packed with the use of ULW-proppant technology pumped for a local operator.

Review and Perspectives of Coated Proppant Technology

“…The second is to use resin to coat the surface of porous proppant. The resin does not invade the internal pores of the proppant, and the air is encapsulated in the proppant to reduce the density …”

“…Aiming at the problems of low fracture pressure, serious leakage, and difficult proppant migration in horizontal wells during well completion in offshore oilfields in Brazil, the use of low-density proppant can reduce the pumping speed of fracturing fluid and reduce fluid leakage . By using coated walnut shell proppant and coated porous ceramic proppant (Figure ) to complete wells in 50 oil wells in an oilfield offshore Brazil, the results show that the settling rate of the low-density proppant is 75% slower than that of the conventional ceramic proppant.…”

Progress of Polymer Application in Coated Proppant and Ultra-Low Density Proppant

“…The practical application of epoxy coated ceramic proppant was investigated by Fan and co-workers [34], the self-suspension ability of the coated proppant increased by 16 times, the hydrophobicity and conductivity were increased by 83.8% and 16.71%, respectively. ULW-1.75 is the most popular commercial coated ceramic proppant [35,36], which has an average porosity of 50% and can form a ULDP with apparent density of 1.75 g•cm −3 . In addition, the closing pressure of 56 MPa can be tolerated at 121 • C.…”

Synthesis of Low-Density Heat-Resisting Polystyrene/Graphite Composite Microspheres Used as Water Carrying Fracturing Proppants

“…From this table, the sphericity of PS=graphite composite microspheres were above 0.9, which were obviously better than quartz sand (0.7) and resin-coated sand (0.8). Good sphericity and roundness provided the high proppant-pack porosity, leading to the increase of permeability at higher stresses with little effects from temperature; meanwhile, perfect sphericity can improve the flow conductivity of proppant [24,25] .…”