缝网压裂技术综述
IUT GROUP (China), LLC
2010/8/24
缝网压裂技术综述
缝网压裂理论是近年来伴随天然裂缝 性油气藏压裂理论研究而发展起来的一项 新型压裂理论和工艺技术。 德克萨斯大学的 Jon E.Olson和Arash Dahi-Taleghsni 针对压裂时多裂缝的同时 延伸和它们与天然裂缝之间的相互作用进 行了长达20年研究。
Production from Barnett shale requires horizontal drilling and fracturing technology. Source: Oil and Gas Investor, January 2006
Fracture Stimulation
n
When drilling for natural gas in shale, the shale must be fracture stimulated ( fraced to release the gas. The well does not produce commercial quantities of gas until it is fraced. Fracing a well involves placing a mixture of water and sand down the well at high pressures to fracture the shale.
SH unkn
2.0 0.0020
5.0
10
20
50
0.0050
New skills / technology
Unconventional Gas Shale Gas
Global resource estimated at 16,112 Tcf(3,842 Tc fin US) –NPC 2007
US shale gas industry • Technological breakthroughs in completion technology reducing costs - 1998 slick water fracturing replaced gel fracturing - 2002 horizontal drilling and fracturing • Shale gas is only produced in US - contributing 6% total gas supply in 2006 - Principal play is the Barnett Producing close to 3.5 Bcfed from about 8100 wells
Res P res M P a
6 .0 0 1 2 .0 0
1 5 .0 0 3 0 .0 0 0
CAL in
0 100 200
-1 2 4 -3 0 .7 0 6 2 .3 8
DT C us/ft
240 1 4 0 4 0 .0 0
CNC % TH p p m
1 .9 52 .4 52 .9 5
R S Oh m m EPOR %
Conventional techniques
• Require “advanced” drilling, completion and stimulation practices • Fields consist of 100s to 1,000s of wells • Success depends upon efficient, low-cost “manufacturing” approach to field development
Unconventional Gas Unconventional Sources of Gas
• Unconventional Gas - Tight Gas - Shale Gas - CBM – - Gas Hydrates
– • Improved technology permits access to – previously uneconomic resources –
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缝网示意图例
天然裂缝储层裂缝发育 – 缝网压裂
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缝网示意图例
StimPlan缝网压裂软件模型
鉴于网状天然裂缝发育的储层，因此Stimplan-shale页岩版本考虑网状天 然缝的因素，在压裂起裂方面与常规地层有所不同，特别在压裂液滤失、 天然缝网启裂、人工裂缝与缝网对净压力的争夺有针对性对原来Stimplan的 部分模块进行了修改，成为Stimplan-Nature Frac Network（缝网压裂版）
缝网输入界面
缝网输入界面
可对缝网的范围、角度、密度、特定层位、启裂级别等定义
缝网输入界面
TVD m 3474.4 Strike Angle Alpha 90 Dip Angle Beta 90 Segments X Distance (m) Fracs /m 50 0.400 3561.7 Click each layer to define fractures
1 .9 52 .4 52 .9 5 0 .2 83 .9 2 7 .5 5
1 0 .0 0
10000
0
2 .5 05 .0 0
3 0 .0 0 4 0 .0 0 5 0 .0 0
GR A g API DT S us/ft ZD E N g /c m3
0 8 .0 0 1 6 .0 0 2 4 0 1 4 0 4 0 .0 0
4 5 .0 0 1 5 .0 0 -1 5 .0 0
K ppm
2 .0 0 1 8 .5 1 3 5 .R D Oh m m PER M m D
1 0 .0 0 10000 0
48 Pcl ( MPa)
68 0 E ( MMpsi)
12 1800 K- Ic
n
What is hydraulic fracturing for Shale?
Hydraulic fracturing is the process of creating fractures, to allow natural gas to flow. In this deep shale gas plays, water, sand and other additives are pumped under high pressure into the formation to create fractures. The fluid is over 99% water and sand, along with a small amount of special-purpose additives. Frac Design for shale is most technical than any other rocks because of the 1. Variables such stress and modulus have much big range; 2 ?? from rock formations and thickness of the targeted shale formation are studied by scientists before hydraulic fracturing is conducted. The result is a highly sophisticated process that optimizes the network of fractures and keeps them safely contained within the boundaries of the deep shale gas formation.
1 0 .0 0 10000 0 5 0 .0 0 100
S ta ti c _ P S _ M o d M M p s i
2200 0.000 0.016 5600 6200 0.0 1.6 130.4 132.8 Loss Coefficient Res Pr es Hor z Per m T emp ( ft/sqr t( min) ) ( MPa) ( md) ( ?C)
正交缝和菱形缝
岩层露头上的天然裂缝
Conventional and Unconventional Gas Plays
Geological setting cartoon
Gas supply Hydrocarbon resource continuum
Resource plays form the “base” of the resource pyramid (large volumes, increased need for technology, more costly to develop)
Net Pressure (MPa) Frac 1
5 0 .0 0 5 5 .0 0 6 0 .0 0 L o g _ Str e s s M Pa
G R A P I D T2 4
us /f Z t D EN g / c c
U ppm
WR M Oh mm
ESW %
0 5 0 .0 0 100
SP mV
天然裂缝储层裂缝发育 – 缝网压裂
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应力临界状态示意图
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缝网计算
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模拟接缝处的破裂模式以得到孔径信息
缝网宽度的计算
软件用二维数值模拟的方式模拟液体在天然裂缝中的流 动 (i.e., vertically as well as away from the hydraulic fracture) 。每个天然裂 缝都假设一个最初的缝宽缝高和渗透率，当液体进入天然裂缝后缝 内压力上升，有效应力的减少提高了裂缝的渗透率。在某些点缝内 液体的压力超过天然裂缝的闭合压力，此时，我们假设天然裂缝的 某一位置的宽度是其压力应力缝高和模量的函数。