Method for production increasing through repeated transformation based on complex crack network

Abstract

The invention provides a method for production increasing through repeated transformation based on a complex crack network. Formation wax and inorganic scale are removed by means of the method that plug removal liquid is injected into a target layer section, then repeated fracturing construction is conducted in a support-free mode, the reservoir transforming volume is enlarged, formation energy isreplenished, fracturing liquid does not flow back after fracturing construction is completed, and by shutting in a well for pressure enlarging, old-well production increasing is achieved. According to the method for production increasing through repeated transformation based on the complex crack network, firstly, by adopting the large-displacement, low-frictional-resistance-slickwater, and support-free modes, repeated fracturing construction is conducted, based on the original complex crack network, the reservoir transforming volume is further enlarged, and the stratum energy is replenished;and secondly, by shutting in the well, under the pressure effect of capillarity tubes, low-frictional-resistance slickwater and remaining oil in medium and small pore throats or matrixes are subjectedto dialysis replacement, and thus the oil well yield and the final recovery percent are increased.

Description

technical field [0001] The invention belongs to the technical field of downhole operations in oil field exploration and development, and in particular relates to a method for increasing production based on complex fracture networks. Background technique [0002] Tight oil reservoirs in the Ordos Basin generally have reservoir characteristics of poor permeability and natural micro-fractures. In the fracturing operation, the concept of "volume fracturing" is used for reference, and the net pressure in the fractures is achieved by optimizing displacement and low liquid viscosity. Conditions allow multiple secondary fractures and micro-fractures to extend along the wall of the main fracture and communicate with each other, eventually forming a complex fracture network in the formation, thereby greatly increasing the productivity of a single well after fracturing. In order to reduce natural decline in the production process of oil wells in tight oil reservoirs after volume fractu...

AI Technical Summary

Problems solved by technology

In order to reduce natural decline in the production process of oil wells in tight oil reservoirs after volume fracturing, water injection wells are often used to supplement formation energy. However, due to poor permeability and strong heterogeneity of tight oil reservoirs, the water absorption capacity of water wells after water injection is not strong. As a result, oil wells are slow to take effect or cannot achieve uniform water injection, and it is difficult to establish an effective displacement system, and the formation energy cannot be fully replenished. At the same time, the main fractures and side fractures formed by large-scale "volume fracturing" communicate with natural fractures to form a complex fracture network , when water injection is used to supplement energy development, there is a risk of fracture water flooding