Much of the embedded software development market has necessarily tight constraints on program size and processor power, hence developers use handwritten C rather than autocode. They rely primarily on testing to find errors in their code.We have an established software development tool known commercially as Perfect Developer, which uses a powerful automatic theorem prover and inference engine to reason about requirements and specifications. We have found that automated reasoning can be used to discharge a very high proportion of verification conditions arising from the specification and refinement of software components described in our formal specification language, Perfect. The Perfect Developer tool set can also generate code in a C++ subset or in Java, and the output code is then virtually certain to meet the stated specification, reducing the need for exhaustive testing. However, this is not helpful to developers of embedded software who are constrained to write code by hand.We therefore decided to investigate whether automated reasoning could provide a similar degree of success in the verification of annotated C code. We present our preliminary findings.

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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^