Method for predicting effective permeability of carbonate gas reservoir

A carbonate rock, prediction method technology, applied in surveying, earthwork drilling, wellbore/well components, etc. The effect of saving test costs, stable gas supply, and saving test costs

Inactive Publication Date: 2018-05-01
PETROCHINA CO LTD
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

However, due to the long test time and high cost, which affect the stable gas supply of gas wells, the proportion of gas wells with well test interpretation in low permeability carbonate gas reservoirs is relatively low, and it is difficult to comprehensively evaluate the effective permeability of gas fields by well test interpretation method
[0007] To sum up, currently commonly used p...

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  • Method for predicting effective permeability of carbonate gas reservoir
  • Method for predicting effective permeability of carbonate gas reservoir
  • Method for predicting effective permeability of carbonate gas reservoir

Examples

Experimental program
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Effect test

Embodiment 1

[0027] This embodiment provides a method for predicting the effective permeability of carbonate gas reservoirs, including the following steps:

[0028] Step 1) Read the wellhead casing pressure recovery data and the gas production data before shutting down of at least 30 gas wells in the gas field that have undergone overpressure recovery test analysis, and obtain the pressure square recovery value of each gas well during the process of gas well shut-in pressure recovery Gas well production q sc and effective permeability K;

[0029] Step 2) Plot the effective permeability K and q SC , Relational intersection diagram of , the effective permeability K and q are obtained after fitting SC , the regression relation;

[0030] Step 3) For the gas wells in the gas field where the pressure recovery well test analysis has not been carried out, according to the obtained regression relational formula, the effective permeability K is calculated by using the gas well production bef...

Embodiment 2

[0034] On the basis of Example 1, this example provides a method for predicting the effective permeability of carbonate gas reservoirs, the pressure square recovery value Gas well production q sc There is the following relationship with the effective permeability K:

[0035]

[0036] In the formula: is the square recovery value of the pressure, the unit is MPa 2 ;q sc is gas well production, unit is 10 4 m 3 / d; K is the effective permeability, the unit is 10 -3 μm 2 ; h is the thickness of the air layer, the unit is m; T is the temperature of the air layer, the unit is K; is the gas viscosity at the average pressure and temperature, in mPa·s; is the gas deviation factor under the average pressure and temperature, decimal; Δt is the shut-in time, in h; t p is the production time before shutting down the well, the unit is h; φ is the porosity, the unit is %: C is the comprehensive compressibility coefficient, the unit is MPa -1 :r w is the radius of the gas we...

Embodiment 3

[0042] In this example, the Jingbian Gas Field is taken as an example. The Jingbian Gas Field has a large area and strong reservoir heterogeneity. A total of 68 typical gas wells in the high, medium and low permeability areas of the gas field were selected, and fine interpretation of pressure recovery test wells was carried out to obtain gas wells. Effective permeability; by reading the casing pressure recovery data of the 68 wells in the 30-day shutdown period and the gas production data before shutdown, K, q sc . Make the regression relationship curve of effective permeability K and other relevant parameters. Comparative analysis found that: when the shut-in time is constant, the effective permeability K and There is a good linear relationship, such as figure 1 shown. After fitting, the effective permeability K and q are obtained SC , The regression relation of is:

[0043] According to the regression relation, the effective permeability of each gas well in Shan ...

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Abstract

The invention provides a method for predicting the effective permeability of a carbonate gas reservoir. Based on pressure recovery well-testing theory analysis and on the basis of influence factor analysis of a low-permeability carbonate reservoir, the relational expression of the effective permeability of the reservoir and pressure recovery data of wellhead sleeves as well as the relational expression of the effective permeability of the reservoir and wellhead yields are built, and a method for evaluating the effective permeability of gas wells through conventional production dynamic materials is formed. According to the method for predicting the effective permeability of the carbonate gas reservoir, the evaluation problem of the permeability of the low-permeability and high-density inhomogenous reservoir under the situation of lacking well-testing evaluation materials is solved, the evaluation range of the effective permeability of the low-permeability gas reservoir is widened by a large margin, and important basic parameters are provided for gas reservoir engineering research such as productivity evaluation and calculation of the gas extraction speed.

Description

technical field [0001] The invention belongs to the technical field of gas field development, and in particular relates to a method for predicting the effective permeability of carbonate gas reservoirs. Background technique [0002] Permeability is an important parameter for reservoir characterization, which is of great significance to gas reservoir engineering research such as determination of gas reservoir gas production rate, gas well productivity evaluation, and numerical simulation. [0003] At present, the evaluation methods of reservoir permeability mainly include core test, well log interpretation and well test analysis. Carbonate reservoirs with low permeability are characterized by tight reservoirs, high degree of heterogeneity, high development well pattern density, relatively low proportion of core experiments and well test analysis in gas fields, and there are certain limitations in using conventional methods to evaluate the effective permeability of gas fields....

Claims

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Application Information

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IPC IPC(8): E21B49/00E21B47/06E21B47/00
CPCE21B47/00E21B47/06E21B49/00
Inventor 田敏伍勇王东旭兰义飞侯科锋张建国刘海锋何磊蔡兴利霍俊洲游良容袁继明谢姗徐运动艾庆琳何依林夏勇王树慧王文胜蔡芳朱长荣乔博
Owner PETROCHINA CO LTD
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