﻿ 提高胍胶压裂液摩阻计算精度的方法

1. 中国石油集团川庆钻探工程有限公司长庆井下技术作业公司, 陕西西安 710021;
2. 低渗透油气田勘探开发国家工程实验室, 陕西咸阳 712000

A Method to Improve the Accuracy of Friction Calculations for HPG Fracturing Fluid
YUAN Haiping1, TAO Changzhou1, GAO Yan1,2, XIA Yulei1
1. Changqing Downhole Service Company, CNPC Chuanqing Drilling Engineering Company Limited, Xi'an, Shaanxi, 710021, China;
2. National Engineering Laboratory of Low Permeability Oil and Gas Field Exploration and Development, Xianyang, Shaanxi, 712000, China
Abstract: At present, calculating the fracturing fluid friction is problematic because there are problems with the ratio of drag, e.g.difficult to find the coefficient, low accuracy of friction calculation, large difference between calculated friction and real one, etc.By combining testing and theoretical methods, the friction calculation method has been improved, i.e.through the indoor small pipe friction test of HPG fluid, fitting and establishing the relationship between the flow velocity and the ratio of drag. Later, the formula was given to calculate the friction of HPG fracturing fluid under different pipe diameters and flow velocities.The indoor and field tests showed that the improved method was accurate in calculating the HPG fracturing fluid friction.Compared with the traditional empirical formula method, the improved method can reduce the difficulty of calculating coefficient of the empirical formula, and improves the accuracy of HPG friction calculation.In this case, the average relative error of calculated friction and real friction is less than 16%, while that of the traditional empirical formula is up to 31%.The research results indicates that the improved method can improve the calculation precision of HPG fracturing friction, and provide a basis for fracturing design and operation.
Key words: fracturing fluid     HPG     friction     ratio of drag     fitting     regression analysis

1 摩阻的经验计算公式

 (1)

 (2)

 (3)

2 摩阻计算方法的改进

 图 1 降阻比与流速的关系曲线 Fig.1 Relationship between ratio of drag and flow velocity

 (4)
 (5)

 (6)

 (7)
3 室内液体摩阻的测定 3.1 试验设备

 图 2 小型液体流动摩阻测试设备示意 Fig.2 Sketch of small test equipment for liquid flow friction
3.2 试验方法

3.3 试验结果分析 3.3.1 清水摩阻

 图 3 不同直径管路中清水流量与摩阻的关系 Fig.3 The relationship between fresh water friction and flow rate in different diameters of pipe
3.3.2 0.08%胍胶基液的摩阻

 图 4 胍胶基液在不同直径管路中流速与降阻比的关系 Fig.4 The relationship between HPG ratio of drag and flow velocity in different pipe diameters
3.3.3 0.08%胍胶基液的降阻比

 (8)

 (9)

4 改进方法的验证 4.1 室内验证

 图 5 0.08%胍胶基液在ϕ73.0 mm油管中的实测摩阻与计算摩阻 Fig.5 Comparison of measured friction and calculated friction with 0.08%HPG in ϕ73.0 mm pipe
 图 6 0.08%胍胶基液在ϕ88.9 mm油管中的实测摩阻与计算摩阻 Fig.6 Comparison of measured friction and calculated friction with 0.08%HPG in ϕ88.9 mm pipe

 图 7 0.30%胍胶基液在ϕ73.0 mm油管中的实测摩阻与计算摩阻 Fig.7 Comparison of measured friction and calculated friction with 0.30%HPG in ϕ73.0 mm pipe
 图 8 0.30%胍胶基液在ϕ88.9 mm油管中的实测摩阻与计算摩阻 Fig.8 Comparison of measured friction and calculated friction with 0.30%HPG in ϕ88.9 mm pipe

4.2 现场验证

 图 9 Z107井沿程实测摩阻与计算摩阻的对比 Fig.9 Comparison of measured friction and calculated friction along the wellbore of Well Z107

5 结论及建议

1) 提出采用试验和理论相结合的方法来推导不同质量分数胍胶压裂液摩阻的计算方法，与传统经验公式相比，该方法降低了经验公式系数求取的难度，提高了摩阻计算精度。

2) 室内试验和现场实测摩阻结果验证了摩阻计算改进方法的准确性，改进方法计算的摩阻与实测摩阻的平均相对误差在16%以内，而经验公式的相对误差高达31%。

3) 建议后续开展更多的室内和现场试验，建立不同压裂液在不同直径管柱和排量下的摩阻图版，为压裂设计和施工提供依据。

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#### 文章信息

YUAN Haiping, TAO Changzhou, GAO Yan, XIA Yulei

A Method to Improve the Accuracy of Friction Calculations for HPG Fracturing Fluid

Petroleum Drilling Techniques, 2017, 45(5): 108-112.
http://dx.doi.org/10.11911/syztjs.201705019