Analysis of Hydraulic Fracture Closure in Laboratory Experiments

Abstract

CC?Yrwht 1S9S, S@Iely of Pelroteum Engrneem, IncThis paper was prepared for pmsantation qt the SPE/lSRM Eurcck '9S held In TrwMhelm, Norway, S-10 Jufy 1S9S, This paper Ws selected for pree.wltdicm by an SPE Program Ccinmittae Iotlowfng review of infonnatmm cc+xained in an abstmcf sutmitfod by the author(s). CcmIents of the paper, as presented, have not been rwiewed by the Sceiety of Petroleum Engineers and we sub~to mrrectm by the Mhor(s), The nwlerml, as presented, daes not necassanty reflecl any Pition of Ihe S-xIely of Pelrokum Engineers, its officars, or~rs.PaPars presented al St% meefing$ are subm 10 publication rwiew by Editorial Cammimees C4 the .%x&y of Petroleum Engineers. Electrcoic reprcducfion, distributicm, or storage ot any parl of this paper Ior commarciaI purposes Wfhotd m. wmtem rxnsent of the Society of Petroleum Engineers Is prohibited PermiScm 10 r.prodtm in prfnt is restricted to cm abstract of not more than s00 words dlustraticms may not ba copied. Ttw abstract must ccotain .xasplcuoua admowledgnwnt of where and by tiom fhe paper was presentsd Write Librarian, SPE, P,O, Son SSSSSS, Richardson, TX 75063-S4)S6, U. S.A., fax 01-97S-952+4SS, AbstractConventional models of hydraulic fracture closure make assumptions about the fracture geometry and rock mechanical behaviour. In this paper we present the results of scaled laboratory experiments. We show that deviations from conventional assumptions influence leak-off volumes, mechanical behaviour, and pressure decline significantly. We discuss mechanisms that lead to deviations from assumptions during fracture closure,

Impact of Rock Plasticity on Hydraulic Fracture Propagation and Closure

“…When we incorporated the measured radius in plaster in the model and assumed that the closed part of the fracture was impermeable, we indeed found a fair agreement of the modeled fracture volume with the measured volume. 5 Closure at the borehole can be detected directly from the width measurement. The closure point is clearly visible on a plot of pressure vs. G-function (see Fig.…”

Roughness of Hydraulic Fractures: The Importance of In-Situ Stress and Tip Processes

“…Fracture surface roughness in combination with a small displacement of opposing fracture surfaces relative to each other, causes imperfect closing due to the non-matching surfaces. This leads to a residual width after closure, which is observed in laboratory tests 1 , and also in field tests 2 . The residual width leads to a fracture conductivity after closure, which can be so large that proppant volumes can be reduced strongly or even can be omitted 3 .…”

“…Fracture roughness can also cause problems with proppant transport. Further, the presence of a significant residual width influences the wellbore pressure during reopening of a hydraulic fracture 5 .…”

“…We did a number of propagation tests, which showed a good reproducibility (see Refs. 7 and 8).We also performed ultrasonic measurements, which yield information about the fracture radius and width 1,7,9 …”

A semi‐analytical model for capturing dynamic behavior of hydraulic fractures during flowback period in tight oil reservoir

“…Laboratory experiments indicated that the fracture will gradually close with pressure drop within the fracture 12 and the permeability of the fracture will also decay with effective stress increase during a reduction of fracture pore pressure caused by production 13 . During the flowback period, there are many researches 6,7 found that the parameters of the fracture calculated by two‐phase flow data after hydrocarbon breakthrough are less than that calculated by single‐phase flow data before hydrocarbon breakthrough.…”