Testing the Fines Migration Hypothesis for DALLAS - FORT

Testing the Fines Migration Hypothesis for Cased-Hole Gravel/Frac

Pack Impairment Using a Novel Laboratory

Approach2019-NAPS-1.3AUTHORS: Ziheng Yao, Hess CorporationJacob McGregor, Halliburton

DALLAS - FORT WORTH. AUGUST 5-6, 2019.

Outline

2019-NAPS-1.3 Testing the Fines Migration Hypothesis for Cased-Hole Gravel/Frac Pack Impairment

Background

o Problem

o Hypothesis

o Fines migration

Testing

o Program description

o Perforation testing

o Pre-shot core characterization

o Viscosity-corrected rate index

Upwards-directed flow, description, results and findings

Downwards-directed flow, description, results and findings

Conclusions and discussions

Background: Problem


© 2009 Elsevier B.V. Figure 3.50 of Bellarby (2009); reprinted by permission of Elsevierwhose permission is required for further use.

© Society of Petroleum Engineers (SPE). Figure 4 of Han et al. (2011); reprinted by permission of SPE whose permission is required for further use.

Bellarby, J. (2009). Well completion design. Vol. 56. Amsterdam, Netherlands: Elsevier.Han, G., Revay, J., Kalfayan, L. J., Perez, J., Walters, D. A., & Bachman, R. C. (2011). Production and Rock Stability around a FracPacked GOM Well. Society of Petroleum Engineers. doi:10.2118/146419-MS

PI Decline in Typical GOM Deepwater Field Frac pack geometry and production behavior

Background: Fines Migration

2019-NAPS-1.3 Testing the Fines Migration Hypothesis for Cased-Hole Gravel Pack Impairment

© Society of Petroleum Engineers (SPE). Figure 4 of Muecke (1979); reprinted bypermission of SPE whose permission is required for further use.

Origin: “unconfined solid particles made up of clay minerals or nonclay species deposited over geologic time or introduced during completion or drilling operations” (Sarkar and Sharma, 1990).

Size: “particles that pass through a 325 US mesh screen (i.e., particles less than 44 𝜇m)” (Bellarby, 2009).

Sarkar, A K, and M M Sharma. 1990. "Fines Migration in Two-Phase Flow." Journal of Petroleum Technology (Society of Petroleum Engineers). doi:10.2118/17437-PA.Bellarby, J. (2009). Well completion design. Vol. 56. Amsterdam, Netherlands: Elsevier. Muecke, T W. 1979. "Formation Fines and Factors Controlling Their Movement in Porous Media." Journal of Petroleum Technology (Society of Petroleum Engineers). doi:10.2118/7007-PA

When a single-fluid phase is present, fines move with the flowing fluid, unless bridged at pore restrictions.

Background: Fines Interaction with Gravel


For simplicity, we will take fines to mean any freely moving particulate within the system, regardless of its origin or size.

o This includes rock debris generated by the perforating process.

o This may also include induced solids/sand grains due to perforation cavity collapseduring long-term production.

Sand ‘Brushpiling’ in the Interface with Gravel

© Society of Petroleum Engineers (SPE). Figure 12c of Tiffin et al. (1998); reprinted by permission of SPE whose permission is required for further use.

Tiffin, D. L., King, G. E., Larese, R. E., & Britt, L. K. (1998). New Criteria for Gravel and Screen Selection for Sand Control. Society of Petroleum Engineers. doi:10.2118/39437-MS

Testing: Program Description


Modified API RP 19B, Section IV Tests

o Berea Buff sandstone cores perforated with Big Hole charge under downhole condition (overburden, pore pressure, wellbore pressure, casing, cement)

o Flow with gravel/screen fixture to examine impairment due to fines migration

o Perforated core subjected to varying levels of confining stress and flow rates

Schematic of typical API RP 19B Section 4 testing equipment

© American Petroleum Institute (API) provided by IHS under license with API. Figure 13 ofAPI (2014); reprinted by permission of IHS whose permission is required for further use.

American Petroleum Institute. (2014). Recommended Practices for Evaluation of Well Perforators (2nd ed.).

Testing: Program Description


Modified API RP 19B, Section IV Tests

o Berea Buff sandstone cores perforated with Big Hole charge under downhole condition (overburden, pore pressure, wellbore pressure, casing, cement)

o Flow with gravel/screen fixture to examine impairment due to fines migration

o Perforated core subjected to varying levels of confining stress and flow rates

Testing: Perforation Testing


HighAccuracy

Flow Loop

PressureVessel with

Heater Bands

Pre-Shot Core Characterization: Full-Face Axial Flow


Conditioned to a residual brine saturation, odorless mineral spirits used as flowing fluid

The following apply:

o 𝜙 = 23.5%

o UCSdry = 4,400 psi

o UCSsat = 4,300 psi

Pre-shot flow testing: Full-Face Axial Flow

o Axial 𝑘𝑒𝑜 = 589 ± 22 md

o Axial 𝛽𝑒𝑜 = 3.96 ± 1.18 atm−s2/g

Berea Buff Sandstone

8.5-in.

18-in.

Full-Face Axial Liquid Flow

Pre-Shot Core Characterization: Restricted-Face Flow


Restricted-Face Axi-Radial Liquid Flow

Restricted-Face Flow

Flow Path

Pre-shot flow testing: Restricted-Face Axi-Radial Viscosity-

Corrected Rate Index, RI∗ = 3.01 ± 0.09cm3−cps−atm

Testing: Viscosity-Corrected Rate Index Determination


Forchheimer, P. 1901. Wasserbewegung durch Boden. Zeitschrift des Vereines deutscher 45 (50): 1781-1788Jones, L. G., Blount, E. M., & Glaze, O. H. (1976). Use of Short Term Multiple Rate Flow Tests To Predict Performance of Wells Having Turbulence. doi:10.2118/6133-MS

Non-Darcy flow can be expressed by Forchheimer (1901) Equation:

oΔΦ

𝐿=

𝜇

𝑘𝑑

𝑞

𝐴+ 𝛽𝜌

𝑞

𝐴

2(Eqn. 1)

Eqn. 1 can be rearranged as (Jones et al., 1976):

oΔΦ

𝑞=

𝜇𝐿

𝑘𝑑𝐴+

𝛽𝜌𝐿

𝐴2𝑞 (Eqn. 2)

oΔΦ

𝑞𝜇=

𝐿

𝑘𝑑𝐴+

𝛽𝐿

𝐴2⋅𝜌𝑞

𝜇(Eqn. 3)

Reciprocal Rate Index (RRI)

RRI* Rock +Geometry

FluidProp.

Data plotted in accordance with Eqn. 3:

RRI* values determined using a least-squares linear regression, extrapolating to the y-intercept where the flow rate is zero:

o RRI∗ ≡ lim𝑞→0

ΔΦ

𝑞𝜇(Eqn. 4)

Viscosity-corrected rate index then found as:

o RI∗ = 1/RRI∗ (Eqn. 5)

Perforation


Core shot while subjected to axi-radial pressure/flow boundary condition

Significant DUB 9,302 psi, applied in attempt to obtain debris-free perforation cavity

Post-Shot Flow 1: flow immediately after shot

Post-Shot Flow 2: flow with gravel pack and screen fixture

Post-Shot Flow 3: continue Flow 2 with staging up confining pressure

Testing: Particle Size Distribution


44 𝜇m

44 𝜇m

D50~115 m

D50~108 m

Testing: Gravel Pack and Screen Fixture


Post-Shot Flow 2

Post-Shot Flow 3

Before Post-Shot Flow 2 testing:

o ~50% (volume) of perforation debris excavated and back-filled with proppant

o Casing-Cement coupon replaced with a gravel pack and screen fixture

o Proppant: uniform 25 mesh high strength ceramic (D50 = 810 m)

Testing: Upwards-Directed Flow


Post-Shot Flow 1: Perforation greatly enhances flow efficiency comparing to intact core.

Post-Shot Flow 2: Flow efficiency is impaired due to the extra impedance caused by gravel/screen fixture.

Post-Shot Flow 3: With increasing confining stress, flow efficiency gets lower.

Testing: A Closer Look at Post-Shot Flow 3’s Data


Core survived 11,000 psi confining pressure (10,000 psi effective stress).

RI* continuously decreases with increasing effective stress, but no ‘breakover’ point is observed.

Testing: Downwards-Directed Flow


1 2 3

4 5

Testing: Methodology for Testing Hypothesis


ΔRRI∗ (discrepancy)

Testing Methodology

The prediction leads to the following expectation for the results if the hypothesis holds true:

Testing: Flow Data

2019-NAPS-1.3 Testing the Fines Migration Hypothesis

Pc = 2,000 psi

Pc = 6,000 psi

Pc = 8,000 psi

Pc = 10,000 psi

Testing: Error Analysis and Conclusion


discrepancy = 0.003 (atm-s)/(cm3-cp)

y-intercepts of RRI* Plots

Consistent with the upwards-flow test, RRI* increases (meaning RI* decreases) with increasing confining pressure.

The ‘Descending DP’ RRI* is consistently higher than ‘Ascending DP’ RRI*. That means RI* during ‘Descending DP’ is lower than that in ‘Ascending DP’, which nominally supports fines migration hypothesis.

However, the error analysis shows the difference is in the range of error bar. There is no significant pore throat plugging to cause PI decline in this test set up.

Conclusions/Discussions/Recommendations


Conclusion: The productivity index before and after high-rate flow did not significantly change for any of the confining pressures tested. This suggests that no significant pore throat plugging had occurred in this specific laboratory setup.

Fully packed vs. partially packed

Particle size distribution (Saucier criterion)

Clean sand sample (XRD)

Flow time

Recommendations for future testing:

1. Use actual reservoir core

2. Test partially packed perf

3. Prolong flow time

2019-NAPS-1.3AUTHORS: Ziheng Yao, Hess CorporationJacob McGregor, Halliburton.

DALLAS - FORT WORTH. AUGUST 5-6, 2019.

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Testing the Fines Migration Hypothesis for DALLAS - FORT