A large-displacement composite acid fracturing method for carbonate reservoirs

A carbonate rock reservoir, composite acid fracturing technology, applied in chemical instruments and methods, earthwork drilling, drilling composition, etc., can solve the problem of insufficient reformation of micro-fracture seepage channels and inability to achieve large displacement Construction, acid-rock reaction rate is fast, etc., to achieve the effect of improving reservoir conductivity, increasing length, and reducing reaction rate

Active Publication Date: 2021-06-01
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The corrosion inhibition effect of these two types of substances is weak, and large-displacement construction cannot be realized, and the acid-rock reaction rate is too fast, the penetration distance of acid or slick water is short, the length of acid-etched fractures is short, and the micro-fractures of the stimulated reservoir Insufficient reconstruction of seepage channels

Method used

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  • A large-displacement composite acid fracturing method for carbonate reservoirs
  • A large-displacement composite acid fracturing method for carbonate reservoirs
  • A large-displacement composite acid fracturing method for carbonate reservoirs

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0060]A large displacement method of carbonate reservoirs, including the following steps:

[0061]Step 1: Depending on the results of logging or rock core experiment, obtain crack growth in carbonate rock reservoirs, rock brittleness and horizontal stress evaluation results, depending on obtaining crack growth in carbonate reservoirs, rock brittleness and horizontal stress The evaluation results are selected to implement a reservoir of large displacement composite acid pressure transformation;

[0062]The selection can implement a reservoir of large displacement composite acid pressure modifications, including the following conditions:

[0063](1) Evaluating the degree of crack development of the reservoir according to the logging or rock core experiment, selecting a crack of 3 or more generic reservoirs per rice, average crack length>20cm;

[0064](2) Evaluate the brittle evaluation of reservoir rocks based on logging or rock core experiments, and the strain should be selected when the reservo...

Embodiment 2

[0074]Preferred carbonate reservoirs large displacement composite acid pressure retrovation method, including the following steps:

[0075]Step 1: Depending on the results of logging or rock core experiment, obtain crack growth in carbonate rock reservoirs, rock brittleness and horizontal stress evaluation results, depending on obtaining crack growth in carbonate reservoirs, rock brittleness and horizontal stress The evaluation results are selected to implement a reservoir of large displacement composite acid pressure transformation;

[0076]The selection can implement a reservoir of large displacement composite acid pressure modifications, including the following conditions:

[0077](1) Evaluating the degree of crack development of the reservoir according to the logging or rock core experiment, selecting a crack of 3 or more generic reservoirs per rice, average crack length>20cm;

[0078](2) Evaluate the brittle evaluation of reservoir rocks based on logging or rock core experiments, and the s...

Embodiment 3

[0116]Referfigure 1 withfigure 2In this example, the C1 well as an example, the C1 well is a certain block of the ancient border of the ancient border, the gas layer is 3860-3890m, the formation temperature is 118 ° C, the pressure gradient is 0.96MPa / 100m, the permeability of 0.15-0.36md, the porosity is 4.2-6.4%. From the perspective of trensel, it is mainly a gray-compact powder crystalline, a small amount of solving stone and muddy, and the crack is more developed. The well is used in 71 / 2 casing, and the fracturing modification is 23 / 8"Tube, from the oil, the casing is empty into the fracture. In order to fully transform the well-white cloud reservoir, the natural crack of depth acidic, communication reservoir is achieved, and the design of large-scale composite acid pressure modification is designed.

[0117]The specific implementation steps are as follows:

[0118]Step 1: According to the logging result of the logging or rock core experiment in the C1 well, it is obtained from th...

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Abstract

The invention relates to the technical field of fracturing in oil and gas fields, in particular to a large-displacement composite acid fracturing method for carbonate rock reservoirs, which reduces the acid reaction rate by using slick water, gelling acid, and viscous acid for multi-stage alternate injection , increase the length of acid-etched fractures, which is conducive to the communication of natural fractures and increase the volume of reservoir acid fracturing; the use of wormhole acid-acid system can realize the deep penetration of acid in fractures, forming a longer effective distance and improving Conductivity; the use of resistance-reducing acid in the later stage can expand the acid erosion degree of the reservoir around the wellbore and further improve the reservoir conductivity in the near-wellbore zone; volumetric acid fracturing of carbonate reservoirs with well-developed fractures can make full use of The natural fractures of the reservoir, with the help of acid solution on the dissolution of carbonate minerals, expand and extend the fractures and caves, at the same time, communicate with natural fractures, increase the diversion capacity of seepage channels, and achieve the purpose of maximizing production increase.

Description

Technical field[0001]The present invention relates to the field of oil and gas field fracturing technology, and more particularly to a large displacement method of carbonate reservoirs.Background technique[0002]Since the carbonate reservoir is generally buried in the depth of 3200 m-4200m, the temperature and the closed pressure are high, so the acid-compulsive modification of the carbonate oil is facing a lot of difficulties: (1) reservoir belongs to the low pore, specialty The reservoir is poor; (2) crack is more developed, and the distribution is uneven; (3) due to its deep temperature, the temperature can reach 120 ° C, resulting in a fast acid rock reaction rate, affecting crack acid erosion The distance is extended, it is difficult to effectively achieve deep penetration, bringing difficulties to effective storage of wellborescent or cavity.[0003]At present, two types of substances are used in the acid compression process to solve the above challenges: (1) High bond acid (thic...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B43/27C09K8/74
CPCC09K8/74C09K2208/32E21B43/26
Inventor 牟春国马旭陈宝春白建文马占国贾建鹏何平韩巧荣马新星李树生
Owner PETROCHINA CO LTD
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