Patent RU-2453695-C1 (RU)
Inventor: IBRAGIMOV NAIL GABDULBARIEVICH
IPC: E21B43/26
Filed: 2011-09-06
Granted: 2012-06-20
Abstract: FIELD: oil and gas industry. 
     SUBSTANCE: method involves pumping of fracturing fluid and fracturing fluid with proppant to formation, and namely through the well to the fracture created in underground formation. According to the invention, first, analysis of service water is performed, and gelling agent is tested for solubility in water and structure formation. If the result is satisfactory, gelling agent is dissolved in water and tested again for structure formation. If results are satisfactory, clay stabiliser, demulsifier and destruction regulating component is added to solution of gelling agent in water; the obtained solution is pumped to the well, and decomposer and cross-linking agent is added to the solution during pumping process, thus forming fracturing fluid. Volume of the well is replaced with fracturing fluid, pumping is stopped and pressure decay is recorded; pumping of fracturing fluid is restored with working flow rate per hydraulic fracturing; fracturing fluid blanket is pumped in the volume of 3 to 6 m 3 . Then, trial sequence of fracturing fluid with proppant is pumped, brought to perforation interval, initial wellhead pressure is marked, and after that, its behaviour is recorded as the sequence passes through perforation interval and moves along the fracture. The above sequence is forced through with fracturing fluid without proppant. Forcing-through is stopped and pressure reduction is recorded; intensity of wellhead pressure reduction is recorded and processed. The obtained data is processed; data on operating efficiency of fracturing fluid, value of pressure, formation stress gradient, time and pressure of fracture closing, pore pressure in manifold, hydraulic pressure losses at perforation interval and bottom-hole part of formation is obtained. Adaptation of design data on hydraulic fracturing process to the obtained test pumping processing data is performed on the basis of the obtained data. Updated data is used for re-calculation of three-dimensional model of hydraulic fracturing and performance of specified version of hydraulic fracturing. Initial plan of the main hydraulic fracturing process is changed by changing initial data on mining-and-geological coefficients for the one obtained with the programme after test pumping is performed; the main hydraulic fracturing process that was changed is performed. When the main hydraulic fracturing process that has been changed is performed on the basis of the made calculations, the required volume of service water is taken, gel is prepared and test is performed. If the test results are satisfactory, hydraulic fracturing process is performed in compliance with the changed plan, where volume of final forcing-through is determined as sum of volume of tubing string and zone under packer to the roof of perforation interval. Mixture of proppant and gel is pumped in two portions; proppant concentration in the first portion is up to 300 kg/m 3 . Proppant concentration in the second portion is more than 300 kg/m 3 . The well is left in order to wait for pressure reduction. When the time required for gel destruction elapses, bleeding of residual wellhead pressure to atmospheric one is performed; well head is depressurised; packer is removed, and underground equipment is lifted. 
     EFFECT: improving monitoring quality of hydraulic fracturing process and expedition of well placing on production. 
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