Well Fan 116-3HF is a development horizontal well deployed in Fan 116 block of Daluhu Oilfield during the "Twelfth Five-Year Plan" period, after the first fracturing, the fracturing fracture spacing in this block is large (100-150m), the proportion of unused area is high, affected by the fracturing scale and transformation volume, the overall recovery degree is low, and the horizontal section has a good potential for repeated fracturing volume fracture network.
In view of the above situation, the Fracturing Institute of the Chinese Academy of Engineering, together with relevant departments and research units in the institute, has set up a technical research team to form a multi-stage staged fracturing horizontal well repeated fracturing technology through pre-pressure reservoir evaluation, wellbore reconstruction cementing and completion, reconstruction volume fracture network fracturing technology, horizontal well energy replenishment, etc., and focuses on "identifying potential, strengthening energy replenishment, wellbore reconstruction, cementing guarantee, double-layer casing perforation optimization, fracture network reconstruction" and other aspects to carry out technical support and application exploration.
Identify the potential
In order to improve the pertinence of repeated fracturing, the residual oil distribution of tight oil horizontal wells and the method of selective selection of repeated fracturing were studied by means of reservoir numerical simulation, production dynamic analysis, and comprehensive evaluation of pre-fracturing reservoirs, so as to identify the potential of repeated fracturing.
Intensive energy replenishment
In view of the low formation energy of the well group in the old well area and the difficulty of energy replenishment in horizontal wells, the pressure flooding energy replenishment technology of horizontal well group was carried out from the aspects of energy replenishment mode, energy replenishment speed, water injection and supporting measures, so as to fully replenish the formation energy.
Wellbore reconstruction
In view of the difficulty of small casing in the long well section, according to the well trajectory, casing size and fracturing discharge requirements, the software optimizes the calculation and simulation of the well to ensure the smooth entry of the small casing.
Solid Guarantee
In order to solve the problem of small gap cementing in the long horizontal section of double-layer casing, the cementing mud formula and dosage were optimized through laboratory experiments to improve the cementing quality of the horizontal section after wellbore reconstruction.
Double-layer casing perforation optimization
In view of the small diameter of the casing after the wellbore reconstruction, the limited size of the perforating gun, and the problem that the perforating bullet should penetrate two layers of high-strength casing and two layers of cement ring, the size of the perforating gun and the type of perforating bullet were determined through the large object model target experiment, so as to ensure that the perforating gun can go down during the construction process and strengthen the perforation penetration.
Mesh reconstruction
In view of the unreformed well section of the first fracturing, the interference of new and old fractures, the stress field changes caused by production and energy replenishment and other factors are comprehensively analyzed, and the fracturing parameters such as segmented clustering, construction displacement, and sand addition scale are reasonably optimized by numerical simulation means to ensure that the reservoir is fully transformed.
Through technical research and integrated support, the "Shengli Tight Oil Horizontal Well Reconstruction Wellbore Repeated Fracturing Technology Version 1.0" has been formed, and the field tests of the overall pressure flooding energy supplement, solid casing in the casing, deep penetration double-layer casing perforation, and reconstructed volume fracture network have been successfully carried out in the Fan 116 well group, and the fracturing construction of the Fan 116-3HF well has been successfully completed at the beginning of the new year of 2024, realizing a breakthrough in the repeated fracturing technology of the wellbore reconstructed for long horizontal wells in the oilfield.
The successful implementation of repeated fracturing in the horizontal well of Well Fan 116-3HF not only enriches the technical system of oilfield fracturing, but also provides strong technical support for the reconstruction and production improvement of horizontal wells of tight oil in the oilfield, which will further liberate the remaining oil potential between the layers of tight oil horizontal wells and improve the development effect of horizontal wells in Shengli low permeability reservoir.