Effects of Fracturing Fluid Velocity on Fluid-Loss Agent Performance

Hall, C.D.; Dollarhide, F.E.

doi:10.2118/736-pa

Cited by 19 publications

(3 citation statements)

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“…(2) where the dynamic leakoff coefficient, C w = 112m, depends heavily on shear, and the spurt loss remains the same as in Eq. 1 and independent of the shear rate.…”

Section: Dynamic Vs Static Testsmentioning

confidence: 99%

Fracturing Fluids: Fluid-Loss Measurements Under Dynamic Conditions

Roodhart

1985

Society of Petroleum Engineers Journal

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When filter-cake-building additives are used in fracturing fluids, the commonly applied static, 30-minute API filtration test is unsatisfactory, because in a dynamic situation (like fracturing) the formation of a thick filter cake will be inhibited by the shearing forces of the fracturing fluid. A dynamic, filter-cake-controlled, leakoff coefficient that is dependent on the shear rate and shear stress at the fracture face is, therefore, introduced. A test apparatus has been constructed in which the fluid leakoff is measured under conditions of temperature, rate of shear, duration of shear, and fluid-flow pattern as encountered under fracturing conditions. The effects of rock permeability, shear rate, and differential pressure on the dynamic leakoff coefficient are presented for various, commonly used fracturing-fluid/fluid-loss-additive combinations.

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“…(2) where the dynamic leakoff coefficient, C w = 112m, depends heavily on shear, and the spurt loss remains the same as in Eq. 1 and independent of the shear rate.…”

Section: Dynamic Vs Static Testsmentioning

confidence: 99%

Fracturing Fluids: Fluid-Loss Measurements Under Dynamic Conditions

Roodhart

1985

Society of Petroleum Engineers Journal

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“…The "initial leakoff velocity" v, (discussed in Ref. 1) was made high enough to prevent the anomalous interference with filter cake initiation observed under certain circumstances in the earlier studies. ;.…”

Section: Crude Oilsmentioning

confidence: 99%

Performance of Fracturing Fluid Loss Agents Under Dynamic Conditions

Hall

Dollarhide

1968

Journal of Petroleum Technology

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Fluid loss agents for crude oil and for water have been studied in dynamic tests. A treatment using a spearhead with a fluid loss agent followed by plain fluid appears feasible in crude oil, but not in water. An equation for spearhead depletion shows that spurt loss relative to fracture width must be low, if the portion of spearhead fluid in the treatment is to be small.The presence of colloidal matter in crude oils aids the fluid loss agent. Unlike in kerosene, where flow limited the agent deposition, in crude oils the filter cake continually formed and leak-off declined. The volume-time relation varied somewhat for different crudes, but was best described by a square root of time function. Spurt loss was inversely proportional to agent concentration. After the fluid loss agent initiated the filter cake, the crude oil colloids built on it effectively. A 2-minute or a 5-minute spearhead with double the normal agent concentration gave the same fluid loss curve as the same concentration did for a 30-minute test.The agents tested in water gave fluid loss plots on which, for the first few minutes, volume was proportional to the square root of time, but later became proportional to time. For fracture area calculation the customary square root of time function is a satisfactory approximation. Leak-off rates and spurt losses were higher in water systems than in oils. The spurt loss tended to be inversely proportional to concentration. In spearhead tests, the filter cakes were not eroded by water flow. However, the rather high spurt loss values make spearhead treatments impractical for water-based fluids.

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“…Table 1 attempts to classify the more significant parameters into the following categories:-(1) rock properties (2) properties of the wellbore fluid (3) physical conditions in the wellbore From the number of mechanisms shown it is clear that the control of formation damage is very difficult.…”

Section: Introductionmentioning

confidence: 99%

The Analysis of Filtration Under Dynamic and Static Conditions

Peden

Arthur

Avalos

1984

SPE Formation Damage Control Symposium

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This paper presents an overview of the work carried out to date on the dynamic and static filtration characteristics of drilling muds. Factors controlling fluid loss to the formation that have been investigated include annular velocity, fluid temperature, hole angle, shear rate and the effect of the filter media. The effect of pressure on static fluid loss and filter cake permeability is also reported. Fluid loss during sequential filtration has also been evaluated. The fluids used comprised a calcium chloride brine with fluid loss additive and two water based muds. The filter media consisted of synthetic core material and a natural sandstone. Conventional photographic techniques have been used to identify filter cake response to backflushing. Introduction The occurrence of a change in permeability of the formation near the wellbore is most frequently related to the effects of the invasion associated with borehole filtration. As filtration proceeds the filtrate, with its accompanying fine particles, creates an invaded zone. Within that zone the productivity may be reduced by physical and/or chemical change to the formation rock or fluids and this impairment is commonly referred to as formation damage. Some appreciation of the complexity of this process can be obtained by considering the range of variables which could affect fluid loss in a borehole. Table 1 attempts to classify the more significant parameters into the following categories: parameters into the following categories:rock propertiesproperties of the wellbore fluidphysical conditions in the wellbore From the number of mechanisms shown it is clear that the control of formation damage is very difficult. It is likely that more that one mechanism may be operating at any one time and, since formations are not homogeneous, there will be variations in the extent to which these individual mechanisms occur. Limiting the extent of filtrate invasion is important and over the past 3 decades or so a great deal of time and effort has been spent on this past 3 decades or so a great deal of time and effort has been spent on this problem. Among the reasons for attempting to quantify and reduce the problem. Among the reasons for attempting to quantify and reduce the volume of mud filtrate are the following:invasion of filtrate with associated fine particles may create a zone of reduced permeability around the wellbore which may not respond to backflushing and results in lower production rates than anticipated.filtrate that penetrated shale sections may cause swelling and subsequent sloughing into the wellbore. Stuck pipe may then be a problem.the location of a zone of mud filtrate around the wellbore will affect the response of electrical logging tools. Correct interpretation of the logs requires accurate knowledge as to the extent of this zone.knowledge of the depth of invasion is required for the determination of perforation depths and possibly for the selection of stimulation treatment. Utilising muds with improved filtration control characteristics provides an efficient method of limiting the extent of the invaded zone. provides an efficient method of limiting the extent of the invaded zone. However it is impossible to eliminate fluid loss entirely since the formation of a low permeability filter cake necessarily involves invasion. Therefore attempts to minimise fluid loss must be accompanied by obtaining information as to the permanency of damage and possible techniques for its removal. p. 283

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Effects of Fracturing Fluid Velocity on Fluid-Loss Agent Performance

Cited by 19 publications

References 0 publications

Fracturing Fluids: Fluid-Loss Measurements Under Dynamic Conditions

Fracturing Fluids: Fluid-Loss Measurements Under Dynamic Conditions

Performance of Fracturing Fluid Loss Agents Under Dynamic Conditions

The Analysis of Filtration Under Dynamic and Static Conditions

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