A real-time acid concentration control method for acid fracturing in oil and gas fields

A technology of acid fracturing and acid concentration, which is applied in chemical instruments and methods, mixing methods, earthwork drilling and mining, etc. It can solve the problem of insufficient supply of acid liquid, consumption of effective seepage channels by acid liquid, failure to ensure effective acid liquid discharge, etc. problems, to achieve the effect of reducing the number of acid tanks, adapting to environmental protection, and increasing the conductivity of cracks

CN106285612BActive Publication Date: 2019-02-15PETROCHINA CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2019-02-15

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Abstract

The invention provides a real-time acid concentration controlling method for acid fracturing of oil and gas fields. The real-time acid concentration controlling method comprises the following steps that (1) a fracturing blender truck A is connected with acid tanks and water tanks A, and a fracturing blender truck B is connected with water tanks B; (2) an acid inlet of an acid blender is connected with liquid outlet pipelines of fracturing trucks A alternately pumping low-resistance acid and quick water; (3) a liquid inlet of the acid blender is connected with liquid outlet pipelines of fracturing trucks B pumping quick water; (4) a liquid outlet of the acid blender is connected with a wellhead pipeline; and (5) when acid fracturing is conducted, the liquid pumping quantity and the pumping displacement of the fracturing blender truck A are V1 and Q1 obtained through the formulas shown in the specification, and the liquid pumping quantity and the pumping displacement of the fracturing blender truck B are V2 and Q2 obtained through the formulas shown in the specification. According to the real-time acid concentration controlling method for the acid fracturing oil and gas fields, the displacement of the low-resistance acid is adjusted through fracturing blender trucks, real-time acid concentration controlling is achieved, acid concentration is changed step by step, effective action distance is improved, fracture conductivity is increased, optimum modifying effect is achieved, and production safety requirements of the oil and gas fields are met.
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Description

technical field

[0001] The invention belongs to the technical field of acid fracturing in oil fields, and in particular relates to a real-time acid concentration control method for acid fracturing in oil and gas fields. Background technique

[0002] Acid fracturing (acid fracturing) is an effective measure for commissioning and increasing production of oil and gas wells in low-permeability carbonate reservoirs. It reacts with artificial (natural) fracture wall rock through acid liquid to form groove-like or uneven high-permeability channels, thereby improving the seepage condition of oil and gas wells and increasing production of oil and gas wells.

[0003] Multi-stage alternating injection acid fracturing is a commonly used acid fracturing process, but there are two problems in the current conventional method: one is that only one sand mixer is used, and only one liquid outlet of the on-site acid tank is connected to the sand mixer. Insufficient acid liquid supply can not ...

Examples

Embodiment 1

[0026] This implementation provides a real-time acid concentration control method for acid fracturing in oil and gas fields, such as figure 2 shown, including the following steps:

[0027] 1) Connect the A sand mixing vehicle 7 with the acid tank and the A water tank, and the B sand mixing vehicle 8 with the B water tank;

[0028] 2) Connect the acid inlet 5 of the acid mixer to the outlet pipeline of fracturing truck A that alternately pumps water-repelling and slick acid, and the inlet pipeline of fracturing truck A is connected to sand mixer A 7;

[0029] 3) Connect the liquid inlet 4 of the acid mixer to the liquid outlet pipeline of the fracturing vehicle B pumping slick acid, and connect the liquid inlet pipeline of the fracturing vehicle B to the sand mixing vehicle 8 of B;

[0030] 4) Connect the liquid outlet 3 of the acid mixer with the wellhead pipeline 9;

[0031] 5) When injecting slick acid in the high-pressure acid injection stage of acid fracturing construct...

Embodiment 2

[0035] On the basis of Example 1, such as figure 1 As shown, the acid mixer is composed of an outer cylinder 1, an inner cylinder 2, and a liquid outlet 3; the outer cylinder 1 is provided with a liquid inlet 4, the inner cylinder 2 is fixed inside the outer cylinder 1, and the liquid outlet 3 is connected to the outer cylinder 1 end, the end of the inner cylinder 2 is blocked, the front end of the inner cylinder 2 is the acid inlet 5, along the axial direction of the inner cylinder 2, there are liquid outlet holes 6 arranged in sequence from the acid inlet 5 to the end. The inner cavity of the outer cylinder 1 and the liquid outlet 3, the inner cavity and the outer side of the inner cylinder 2 are all sprayed with polytetrafluoroethylene. The diameter of the liquid outlet hole 6 gradually decreases along the axial direction of the inner cylinder 2 .

[0036] The invention utilizes an acid mixer to realize uniform mixing of water resistance and slick acid; the inner cavity of...

Embodiment 3

[0038] On the basis of Example 1 and Example 2, this example uses the real-time acid concentration control method for acid fracturing in oil and gas fields of the present invention to treat the 3390.6m-3410.3m well of Sudong 38-25C2 in Changqing Oilfield. The effective thickness of the interval is 16.5m, and concentrated perforation is carried out near the upper part of the reservoir at 3391.0m to 3395.0m. Design water resistance reduction 71.3m 3 , slick acid 197.3m 3 , Steering acid 50.0m 3 . In the implementation plan, slick acid is used as the pre-fracture-making liquid; the resistance-reducing water etches the main cracks and expands the micro-cracks to form effective seepage channels; the diverting acid increases the viscosity and temporarily plugs the cracks formed in the previous stage, which is conducive to the formation of new cracks by the subsequent liquid .

[0039] During acid fracturing construction, A sand mixing vehicle 7 is connected to all acid tanks and...