A method to convert multiple shot section open hole completions into cased hole completions has been developed and tested. This method provides zonal isolation between shot sections thus helping prevent injection fluid loss to non-pay intervals. The process, called "Puddle-Pack", involves formulating a permeable resin fill material and placing the material in the shot open hole to fill the large voids. The excess material is then drilled out and underreamed to allow a liner to be run and cemented in place. This paper details the necessity for the development of the process, design requirements, laboratory pretesting of the sand-resin mixture, remedial procedures, data demonstrating zonal isolation and profile improvement, and economic advantages of converting these wells to cased hole completions.

To increase productivity of a three zone, shot, open hole completion, a "PUDDLE-PACK" has been successfully completed and all three zones individually stimulated. MCA Unit #103, located in Southeast New Mexico, experienced a 2.75 fold production increase after "PUDDLE-PACK" completing and hydraulically fracturing two San Andres intervals and acidizing one Grayburg interval. The first attempt to hydraulically fracture the lower San Andres zone failed. As a result of the failure to hydraulically fracture the bottom San Andres "PUDDLE-PACK" completed interval, mechanical property and perforation tests were performed on the resin fill material used in the "PUDDLE-PACK" completion process. After analyzing the test data, corrective remedial operations were designed. These remedial adjustments allowed the two San Andres "PUDDLE-PACK" completed intervals to be successfully hydraulically fractured. This paper describes in detail, the need for selective stimulation of MCA Unit #103, one initial remedial operation, the resin coated gravel fill material mechanical properties testing results, the resin coated gravel fill test perforating results, the remedial operation changes required to hydraulically fracture a "PUDDLE-PACK" completed well, and a complete evaluation of well performance. Introduction MCA Unit #103 was "PUDDLE-PACK" recompleted in September, 1986. This was the first attempt at "PUDDLE-PACK" recompleting a producing well to allow selective hydraulic fracturing of pay intervals to increase productivity of the well. MCA Unit #103 is part of the MCA Unit located in southeastern New Mexico, which is currently under waterflood, and has tertiary oil recovery potential (see Figure 1). MCA Unit #103 was perforated underbalanced approximately 300 psi, as shown on the attached wellbore diagram (Figure 2). Stimulation company pump trucks were then rigged up and a fracture stimulation of the 9th Massive, and 9th zones was attempted. A maximum rate of only 2 bbl per minute, at 4500 psi surface injection pressure, was achieved. This rate was well below the required 15 bbl per minute to obtain an equilibrium pack propped hydraulic fracture treatment. Past history of hydraulically fracturing the San Andres, with proppant bearing fluids, on new cased hole wells had indicated that the 16 bbl per minute 4500 psi surface injection pressure was attainable. Examination of the treatment report and calculations led to three possibilities.Only two perforations were open. P. 569^

The ·success of a co 2 flood largely depends on the quality of ~ts injection wells.The wells must confine injection to the desired pay intervals and withstand the corrosive nature of co 2 for the life of the flood.These are difficult goals to achieve considering the primary candidates for co 2 flooding are mature waterfloods where the wells may have been in service for forty years or more.Casing and cementing practices of the past were often inadequate for a long waterflood life, and are certainly unacceptable for a long term tertiary recovery project. This paper describes innovative techniques employed in the MCA Unit, located in southeast New Mexico, for converting old waterflood injection wells into state-of-the-art co 2 injection wells.The solutions de.veloped for tlie MCA CO? Project have considerable application to ofher co 2 projects and can be profitably employed to improve waterflood recovery as well.