Physical Performance Test of Self-propping Solid and Evaluation of the Propped-Fracture Conductivity

In order to solve problems such as sand blockage, equipment wear, and residue damage associated with the current fracturing technology, we develop a method to form self-propping solid (SPS) proppant under formation situation based on phase change. After the liquid material is injected in reservoir, the reservoir temperature stimulates the generation of SPS particles. The size, density, morphological change under pressure, crushing rate, and conductivity of propped fractures were tested to evaluate the SPS performance. The test results show that the size distribution of different types of SPS varies greatly. Therefore, SPSs of different sizes can be formed through adjusting the ratio of raw materials to effectively prop relatively wide tensile fractures, medium wide branch fractures and relatively narrow microfractures. With an apparent density ranging between 1.0g/cm3 and 1.12g/cm3 which is close to that of water, the SPS can be easily carried by fracturing fluid. With a crushing rate between 0.45% and11.65%, which is lower than that of quartz sand and ceramsite, the SPS is used for fracturing of deep reservoirs to prevent crushed parts migrating or blocking the flow channel. The conductivity of different types of SPS is quite different and it is better than that of quartz sand and ceramsite at a closure pressure of 55Mpa. Because the crushing rate of 6/20-mesh SPS-5 samples is high, their fracture conductivity is less than that of other SPSs with a size of 20/40 mesh and 40/70 mesh. Due to the high strength, even being placed in one layer, the SPS can effectively prevent the crushing and embedding of proppant. Compared with conventional proppant, the SPS has distinct advantages.