Summary Conventional gravel pack completions often reduce the wells productivity by increasing the completion skin. This paper describes a methodology backed by a systematic technique to predict the necessary drawdown, frac length, and conductivity to prevent formation failure and remove the completion damage. This method enables the engineer to optimize the fracture dimensions while obtaining the necessary decrease in drawdown near wellbore that would cause the unpacked perforation to fail. This technique will greatly reduce the chance for formation failure and improve the well performance without the need to gravel pack. Introduction Gravel packing has been the standard practice for controlling sand production from producing wells. These treatments are considered successful if the well produces sand free with a minimum drawdown across the perforations. Considerable time, money and research has gone into developing techniques that improve the performance of gravel packed completions by minimizing the damage caused by the completion. Despite these efforts experience has shown that even the most sophisticated sand control technology affects well productivity because of near wellbore damage caused by the gravel pack procedure. Table 1 shows a comparison of skin and productivity index for over 70 wells that have been completed using various completion techniques. As can be seen even the best internal gravel packed wells experience high skins when compared to perforated non-gravel packed wells. It has also been known for a number of ears that applying relatively large volumes of grave at above fracture gradient pressures followed by a internal gravel pack have resulted in less damage and good productivity improvements. These operations, called "Sand Oil Squeezes", were effectively a combination of a gravel pack and a hydraulic fracturing treatment, and are now called "Frac and Pack's". This technology is now being advanced so that the fracturing part of a "Frac and Pack" is not only used to improve the well productivity but also as a sand remediation technique. The sand control is accomplished by reducing the pressure drop across the perforation. Previous investigators merely postulated probable physical mechanisms and field procedures, whereas this paper presents a theory that couples sand production prediction and fracturing. This technique is currently being used in the North Sea and, as described in this paper, in the Gulf Coast of the United States.

A t I O l V t I 0 9 V l 1 V N O I l V N DISCLAIMER Portions of AbstractPatterns of microearthquakes detected downhole defined fracture orientation and extent in the Austin chalk, Giddings field, TX and the 76 field, Clinton Co., KY. We collected over 480 and 770 microearthquakes during hydraulic stimulation at two sites in the Austin chalk, and over 3200 during primary production in Clinton Co. Data were of high enough quality that 20%, 31% and 53% of the events could be located, respectively. Reflected waves constrained microearthquakes to the stimulated depths at the base of the Austin chalk. In plan view, microearthquakes defined elongate fracture zones extending from the stimulation wells parallel to the regional fracture trend. However, widths of the stimulated zones differed by a factor of five between the two Austin chalk sites, indicating a large difference in the population of ancillary fractures. Post-stimulation production was much higher from the wider zone. At Clinton Co., microearthquakes defined lowangle, reverse-fault fracture zones above and below a producing zone. Associations with depleted production intervals indicated the mapped fractures had been previously drained. Drilling showed that the fractures currently contain brine, The seismic behavior was consistent with poroelastic models that predicted slight increases in compressive stress above and below the drained volume.

A t I O l V t I 0 9 V l 1 V N O I l V N DISCLAIMER Portions of AbstractPatterns of microearthquakes detected downhole defined fracture orientation and extent in the Austin chalk, Giddings field, TX and the 76 field, Clinton Co., KY. We collected over 480 and 770 microearthquakes during hydraulic stimulation at two sites in the Austin chalk, and over 3200 during primary production in Clinton Co. Data were of high enough quality that 20%, 31% and 53% of the events could be located, respectively. Reflected waves constrained microearthquakes to the stimulated depths at the base of the Austin chalk. In plan view, microearthquakes defined elongate fracture zones extending from the stimulation wells parallel to the regional fracture trend. However, widths of the stimulated zones differed by a factor of five between the two Austin chalk sites, indicating a large difference in the population of ancillary fractures. Post-stimulation production was much higher from the wider zone. At Clinton Co., microearthquakes defined lowangle, reverse-fault fracture zones above and below a producing zone. Associations with depleted production intervals indicated the mapped fractures had been previously drained. Drilling showed that the fractures currently contain brine, The seismic behavior was consistent with poroelastic models that predicted slight increases in compressive stress above and below the drained volume.

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011.