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Composite blocking-removal method for improving flow conductivity of triple-low sandstone reservoir

A technology for sandstone reservoirs and flow conductivity, which is applied to drilling compositions, chemical instruments and methods, and production fluids, and can solve problems such as increased construction safety risks, complex construction, and many types of fluids

Active Publication Date: 2012-08-15
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this process technology has the following disadvantages: 1. There are many types of liquid preparation, and the construction is complicated. During construction, it is necessary to clean the well first, and then inject the plugging solution into the process.
2. There are no other clay mineral acids in the proportioning thermochemical agent, and the ability to deal with inorganic matter plugging in the formation of "three low" sandstone reservoirs is poor
3. It is necessary to cooperate with oil well measures during construction, and to inject plugging remover into the measure pipe string. The operation process is complicated, which increases the safety risk
However, this technology has the following disadvantages: 1. When the aqueous solution is injected into the well by two sets of pump trucks at the same time, the chemical solvent reacts at the wellhead. Due to the heat loss in the wellbore, the performance of the organic matter in the near wellbore is deteriorated; 2. Compared with other thermochemical agents, there is no other clay mineral acid treatment, which has poor ability to deal with formation inorganic blockage in "three low" sandstone reservoirs; 3. The reaction of chemical solvents in the wellhead or in the wellbore increases the construction safety risk
[0007] Due to the diversity and complexity of formation plugging in low-pressure, low-permeability, and low-mobility reservoirs, the efficiency of plugging removal by single conventional acidizing or HF acid combination is not high

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0099] Example 1: Well Hu 42-10, an oil production well in the Niuquan Lake block of Santang Lake Oilfield, has an average formation permeability of 0.95×10 -3 μm 2 , the formation pressure coefficient is 0.75. After the analysis of the well operation, the liquid volume drops rapidly, the crude oil viscosity is high, and the well fluid has polluted the formation during previous operations. It is preferred to use "ammonium chloride chemical heat generation liquid, sodium nitrite chemical heat generation liquid, active agent liquid The composite plugging removal system of "deep penetrating retarded acid liquid with sandstone" was used to remove plugging and increase production.

[0100] Oil production engineering technicians calculate and confirm the required plugging removal agent dosage according to the formation properties of three-low sandstone reservoirs, single well production, oil layer thickness, porosity, permeability and plugging removal radius and other parameters. ...

Embodiment 2

[0115] Example 2: Well Niu 10-9, an oil production well in the Niuquan Lake block of Santang Lake Oilfield, has an average formation permeability of 6.1×10 -3 μm 2 , formation pressure coefficient 0.75, formation crude oil viscosity 42-67MPa·s. It is analyzed that the viscosity of crude oil in this well is high, corresponding to the poor water flooding condition of the well, it is preferable to increase the amount of active agent liquid to remove plugging and increase the mobility of formation crude oil.

[0116] Oil production engineering technicians calculate and confirm the required plugging removal agent dosage according to the formation properties of three-low sandstone reservoirs, single well production, oil layer thickness, porosity, permeability and plugging removal radius and other parameters.

[0117] The first step: construction preparation: take out the four pre-configured plugging solutions (ammonium chloride chemical heat generation liquid 15m 3 ; Sodium nitrit...

Embodiment 3

[0124] Example 3: Well Niu 12-9, an oil production well in the Niuquan Lake block of Santang Lake Oilfield, has an average formation permeability of 6.11×10 -3 μm 2 , formation pressure coefficient 0.75, formation crude oil viscosity 65MPa·s. According to the analysis, the crude oil viscosity of this well is high, the production cycle of the oil well is long, and the liquid production declines rapidly in a certain period of time. It is preferable to use the compound plugging removal system of "ammonium chloride chemical heat generation liquid, sodium nitrite chemical heat generation liquid, active agent liquid and sandstone deep penetration slow acid liquid" to remove plugging and increase production:

[0125] The first step: construction preparation: take out the four pre-configured plugging solutions (ammonium chloride chemical heat generation liquid 15m 3 ; Sodium nitrite chemical heating liquid 15m 3 ; Active agent liquid 20m 3 ;Sandstone deep penetration slow acid liq...

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Abstract

The invention discloses a composite blocking-removal method for improving the flow conductivity of a triple-low sandstone reservoir, which is applied to the improvement on the flow conductivity of a low-pressure, low-permeability and low-fluidity reservoir in an oilfield so as to improve the outputs of oil wells. The method comprises the following steps of: carrying out preparations for construction, namely respectively filling four kinds of prepared blocking-removal liquid including ammonium-chloride chemical heat-generating liquid, sodium-nitrite chemical heat-generating liquid, surfactant liquid and sandstone deep-penetrating retarded acid liquid into storage and transportation tanks, and transporting the storage and transportation tanks to an oil-well operation site; respectively filling the four kinds of liquid into an oil well by oil tubes or an annular space between an oil tube and a casing pipe; then filling displacement fluid into the oil well; finally closing the oil well, and reacting for four hours so as to complete the composite blocking-removal construction; and opening the oil well, and putting the oil well in oil production. The method disclosed by the invention has the effects that: the reservoir blocking caused by inorganic scales, organic scales and microbial germ contamination can be simultaneously and effectively removed, thereby achieving the purposes of restoring or improving the in-place permeability and improving the outputs of oil wells.

Description

technical field [0001] The invention relates to the field of oil recovery technology, in particular to a method for improving the diversion capacity of low-pressure, low-permeability, and low-fluidity oil reservoirs, and is a composite plugging removal method for improving oil well production in three-low sandstone oil reservoirs. Background technique [0002] During the production process of the oil field, due to the influence of the nature of the oil layer and many factors in the water injection development process, the near wellbore area of ​​the oil layer will be damaged to varying degrees such as blockage, scaling and pollution, resulting in a decline in oil well production. During the development process of low-pressure, low-permeability, and low-mobility "three-low" sandstone reservoirs, due to factors such as crude oil emulsification, "cold damage", and clay particle migration, the production of oil wells has dropped significantly. Currently, single hydrochloric acid ...

Claims

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Application Information

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IPC IPC(8): E21B43/22C09K8/524C09K8/528C09K8/74
Inventor 朱永贤王小龙谢佃和高浩宏钟银周德彬汤爱云刘波
Owner PETROCHINA CO LTD
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