METHOD FOR ACID TREATMENT OF BOTTOMHOLE ZONE OF OIL PRODUCING AND INJECTION WELL Russian patent published in 2024 - IPC E21B43/27 E21B43/22 C09K8/74 E21B49/00 

FIELD: oil industry.

SUBSTANCE: in the method of treating the bottomhole zone of a well equipped with a flexible tubing string, a production well is determined, on which there is a decrease in productivity for 6 months, or injection, on which there is a decrease in injectivity for 6 months, based on the results of hydrodynamic studies, determining the value of the skin factor characterizing the damage to the wellbore zone by a group of complex colmatants, consisting of mechanical impurities, oil products, salt sediments. Most effective acid composition is determined: for use in terrigenous productive reservoirs – an acid composition containing, vol.%: hydrochloric acid 12% with concentration 95–96.5; hydrofluoric acid of 40% concentration 2–3; surfactants 1.5–2, for use on carbonate productive reservoirs – acid composition containing, vol.%: hydrochloric acid of 15% concentration 94–95; surfactants 2–3; iron ion stabilizer 2–3. Data on well and data on results of previously conducted laboratory researches on similar wells are entered into simulator for treatment of bottom-hole zone – reaction rate constants, Gong and Palarini model constants, minimum pore volume before acid breakthrough in core samples. In the simulator, at least 15 scenarios of calculating acid action are carried out, a model with different scenarios of injection rate of acid composition and skin factor value is obtained. From the calculated scenarios, the scenario is selected, at which the range of the acid composition injection rate corresponds to the minimum value of the skin factor. Based on the created well acid treatment design according to the results of unloading from the bottomhole treatment simulator with the obtained values of the injection rate, volume, acid injection pressure, acid treatment of the well is started.

EFFECT: increasing productivity and injectivity of oil producing and injection wells.

1 cl, 2 dwg