Performance Review of Phenolic-Resin Gravel Packing

Abstract

Summary This paper discusses the application of phenolic-resin-coated gravels in forming linerless, behind-the-casing gravel packs as a method of sand control in shallow steam-displacement wells. Laboratory tests were made to determine the effects of steam temperature, flow rate, and pH on the physical properties of the resin-coated sand (i.e., curing, matrix strength, and permeability). These tests, along with posttreatment production history from a 10-well field test, show that phenolic-resin gravel packing is an effective method of sand control. Introduction Getty Oil Co. operates a major steam displacement project in the Kern River field near Bakersfield, CA. Steam is injected continuously into the productive sand via steam injection wells and ultimately breaks through into the producing wells. Many of these producing wells have experienced severe sand problems because the steam carried large quantities of the unconsolidated formation through the perforations.Unique field characteristics, which have discouraged the use of many modern sand-control methods currently employed throughout the industry, include the following.1. Reservoir temperatures generally exceed 120 degrees C and may go as high as 205 degrees C during steam stimulation.2. To reduce the hydrostatic head, the wells are operated in a "pumped-off" condition. Therefore, the sucker-rod pumps must be placed at the bottom of the producing zone.3. Clearance between casing and sucker-rod pumps in many of Getty's 3,000 producing wells is less than 56 mm.These factors prevent running retaining screens for conventional gravel packs and the use of gravel coatings, which are not stable at these temperatures. However, a linerless, behind-the-casing, consolidated gravel pack using a coated gravel that exhibits high-temperature stability is a sand-control method that is compatible with these field conditions.This paper describes the results of laboratory investigations and a field test program on the use of phenolic-resin-coated gravel (PRCG). Laboratory tests investigated the effect of expected field conditions on the physical properties of the PRCG. The results of these experiments were used to define the physical limitations under which these gravels can be used successfully in field applications. The performance of 10 sand-problem wells that were gravel packed using this coated sand is discussed. The results of this entire program show that PRCG can be used successfully to control sand problems in many of the Kern River wells. Theory The material used in these gravel packs consists of sieved, high-quality gravel, of which each grain has been coated with phenolic resin. After placement in the wellbore, the gravel is heated either by conduction from the reservoir or from injected steam. The resin softens as the temperature increases and diffuses to form "necks" between adjacent sand granules. After a finite period of time, the resin thermosets into a hard, inert coating, forming a highly permeable, consolidated gravel pack.The coated gravel does not require preflushes or postflushes to consolidate uniformly when an adequate heat source is available. This becomes increasingly important as treatment interval length increases. JPT P. 221^