METHOD OF OPERATING HORIZONTAL WELLS IN WEAKLY CEMENTED MANIFOLD Russian patent published in 2020 - IPC E21B43/16 E21B43/25 E21B43/02 

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: invention relates to oil and gas industry and can be used in development of deposits using horizontal wells, where oil production is performed from formation with weakly cemented collector. Method of operation provides for treatment of bottom-hole zone of wells with chemical compositions increasing strength of rocks. During development of production wells, mining for production at minimum yield is performed before bottom-hole zone of filtration system is cleaned of small uncemented particles by their removal to surface for at least a day. Then, the well is outputted to the target bottomhole pressure with the initial pressure change rate of not more than 2 atm per day. Rate of reduction of bottomhole pressure is constantly reduced as the value of the current bottomhole pressure is reduced to reduce the concentration of small uncemented particles. At that target bottom-hole pressure is determined by results of combined geomechanics-hydrodynamic simulation based on distribution of petrophysical properties of formation along well shaft, obtained from interpretation results of geophysical studies and specified during well withdrawal to mode. As petrophysical properties of the formation along the borehole there used is, in particular, porosity and permeability of formation rocks. Geomechanic-hydrodynamic modelling establishes connection between created loads at reduction of bottomhole pressure, deformation of rocks and their destruction near well and at distance - in area of pressure funnel. At injection wells development is performed for extraction within 3–6 months till reduction of risks of formation of filtration channels. Downhole pressure in these wells is reduced until signs of rocks destruction appear. As a result, said geomechanics-hydrodynamic modelling and target bottom-hole pressure are specified.

EFFECT: technical result is providing stable operation of well with maximum allowable depression.

1 cl, 3 dwg