Proppant and Fracture Height Measurement from Forgotten Vertical Well Diagnostics

2021 ◽  
Author(s):  
Christopher Lawrence Squires
Keyword(s):  
Hydraulic Fracture ◽  
Height Growth ◽  
Vertical Wells ◽  
Gas Reservoirs ◽  
Height Measurement ◽  
Fracture Geometry ◽  
Role Changes ◽  
Fluid Systems ◽  
Fracture Height ◽  
The Many

Abstract This paper reviews the diagnostic data from vertical wells where operators targeted Burkett, Hamilton and Marcellus Shales and other deeper unconventional shale or tight gas reservoirs with vertical wells between the years 2006-2013. The learnings are then translated for their applicability in horizontal development wells. Its purpose is to deliver a better perception of fracture geometry and interactions between payzones that are separated by potential fracture barriers. Multiple vertical wells employed the use of diagnostics in the form of proppant tracer, production logging and post-fracture temperature surveys to provide an improved understanding of hydraulic fracture and propped fracture height and the formations that serve as hydraulic fracture barriers. Completions variables such as treating rates, proppant volumes, perforation designs and frac fluid systems are examined to determine how they relate to propped fracture height growth. In the majority of the logs reviewed, the proppant was contained to the perforated interval or just above and below. Some wells did have extensive proppant height growth. However, in most of those cases, the propped fracture height was the result of poor cement bonding, multiple fractured intervals growing towards one another and frac plug failures. As expected, hydraulic fracture height is typically significantly higher than the proppant height. Few vertical wells showed evidence of proppant connecting the Marcellus and Burkett zones. Formations acting as fracture barriers did not respond to many of the completions variables. Large treatment volumes, up to 500,000 lbs or more of proppant in a single stage, are often contained to propped fracture heights of less than 50 ft. Few vertical unconventional wells are currently drilled now that most economic Marcellus fairways are well into their development phase. Vertical wells and their learnings are often forgotten with the many personnel and role changes, acquisitions, mergers and other fast paced changes in the industry over the last decade. The purpose of this paper is to reintroduce the valuable and still relevant vital information from these forgotten vertical wells.

Hydraulic-Fracture-Height Growth: Real Data

2012 ◽  
Vol 27 (01) ◽  
pp. 8-19 ◽  
Author(s):  
M. Kevin Fisher ◽  
Norman R. Warpinski
Keyword(s):  
Hydraulic Fracture ◽  
Real Data ◽  
Height Growth ◽  
Fracture Height

Utilizing Microseismic to Monitor Fracture Geometry in a Horizontal Well in a Tight Sandstone Formation

2021 ◽  
Author(s):  
Abu M. Sani ◽  
Hatim S. AlQasim ◽  
Rayan A. Alidi
Keyword(s):  
Horizontal Well ◽  
Fracture Propagation ◽  
Horizontal Stress ◽  
Height Growth ◽  
Tight Sandstone ◽  
Fracture Geometry ◽  
Fracture Length ◽  
Sandstone Formation ◽  
Fracture Height ◽  
Maximum Horizontal Stress

Abstract This paper presents the use of real-time microseismic (MS) monitoring to understand hydraulic fracturing of a horizontal well drilled in the minimum stress direction within a high-temperature high-pressure (HTHP) tight sandstone formation. The well achieved a reservoir contact of more than 3,500 ft. Careful planning of the monitoring well and treatment well setup enabled capture of high quality MS events resulting in useful information on the regional maximum horizontal stress and offers an understanding of the fracture geometry with respect to clusters and stage spacing in relation to fracture propagation and growth. The maximum horizontal stress based on MS events was found to be different from the expected value with fracture azimuth off by more than 25 degree among the stages. Transverse fracture propagation was observed with overlapping MS events across stages. Upward fracture height growth was dominant in tighter stages. MS fracture length and height in excess of 500 ft and 100 ft, respectively, were created for most of the stages resulting in stimulated volumes that are high. Bigger fracture jobs yielded longer fracture length and were more confined in height growth. MS events fracture lengths and heights were found to be on average 1.36 and 1.30 times, respectively, to those of pressure-match.

No Need for Radio Active Tracer When Mother Nature Helps Detecting the Effective Hydraulic Fracture Height

2022 ◽  
Author(s):  
Rinat Lukmanov ◽  
Said Jabri ◽  
Ehab Ibrahim
Keyword(s):  
Hydraulic Fracture ◽  
Natural Radioactivity ◽  
Gamma Ray ◽  
Fracture Propagation ◽  
Radioactive Isotopes ◽  
Main Element ◽  
Tight Gas ◽  
Well Test ◽  
Gas Reservoirs ◽  
Fracture Height

Abstract The tight gas reservoirs of Haima Supergroup provide the majority of gas production in the Sultanate of Oman. The paper discusses a possibility of using the anomalies from natural radioactivity to evaluate the fracture height for complex tight gas in mature fields of Oman. The standard industry practice is adding radioactive isotopes to the proppant. Spectral Gamma Ray log is used to determine near wellbore traced proppant placement. Spectral Noise log in combination with Production logs helps to identify the active fractures contributing to production. These methods complement each other, but they are obviously associated with costs. Hence, majority of wells are fracced without tracers or any other fracture height diagnostics. However, in several brown fields, an alternative approach to identify fracture height has been developed which provides fit-for-purpose results. It is based on the analysis of naturally occurring radioactive minerals (NORM) precipitation. The anomalies were observed in the many gas reservoirs even in cases when tracers were not used. At certain conditions, these anomalies can be used to characterize fracture propagation and optimize future wells hydraulic Fracture design. A high number of PLTs and well test information were analyzed. Since tight formations normally don't produce without fracturing, radioactive anomalies flag the contributing intervals and hence fracture propagation. The main element of analysis procedure is related to that fact that if no tracers applied, the discrepancy between normalized Open Hole Gamma Ray and Gamma Ray taken during PLT after 6-12 months of production can be used instead to establish fracture height. This method cannot be applied for immediate interpretation of fracture propagation because time is required to precipitate NORM and using the anomalies concept. The advantage of this method is that it can be used in some fields to estimate the frac effectiveness of wells without artificial tracers. It is normally assumed that the Natural radioactivity anomalies appear mainly due to co-production of the formation water. However, in the fields of interest the anomalies appear in wells producing only gas and condensate. This observation provides an opportunity for active fracture height determination at minimum cost.

scholarly journals Apparent Toughness Anisotropy Induced by “Roughness” of In-Situ Stress: A Mechanism That Hinders Vertical Growth of Hydraulic Fractures and Its Simplified Modeling

SPE Journal ◽  
2019 ◽  
Vol 24 (05) ◽  
pp. 2148-2162 ◽  
Author(s):  
Pengcheng Fu ◽  
Jixiang Huang ◽  
Randolph R. Settgast ◽  
Joseph P. Morris ◽  
Frederick J. Ryerson
Keyword(s):  
Hydraulic Fracture ◽  
High Stress ◽  
In Situ Stress ◽  
Height Growth ◽  
Hydraulic Fractures ◽  
Simple Relationship ◽  
Vertical Growth ◽  
Stress Profiles ◽  
Fracture Height

Summary The height growth of a hydraulic fracture is known to be affected by many factors that are related to the layered structure of sedimentary rocks. Although these factors are often used to qualitatively explain why hydraulic fractures usually have well–bounded height growth, most of them cannot be directly and quantitatively characterized for a given reservoir to enable a priori prediction of fracture–height growth. In this work, we study the role of the “roughness” of in–situ–stress profiles, in particular alternating low and high stress among rock layers, in determining the tendency of a hydraulic fracture to propagate horizontally vs. vertically. We found that a hydraulic fracture propagates horizontally in low–stress layers ahead of neighboring high–stress layers. Under such a configuration, a fracture–mechanics principle dictates that the net pressure required for horizontal growth of high–stress layers within the current fracture height is significantly lower than that required for additional vertical growth across rock layers. Without explicit consideration of the stress–roughness profile, the system behaves as if the rock is tougher against vertical propagation than it is against horizontal fracture propagation. We developed a simple relationship between the apparent differential rock toughness and characteristics of the stress roughness that induce equivalent overall fracture shapes. This relationship enables existing hydraulic–fracture models to represent the effects of rough in–situ stress on fracture growth without directly representing the fine–resolution rough–stress profiles.

Investigation of Rupture and Slip Mechanisms of Hydraulic Fractures in Multiple-Layered Formations

SPE Journal ◽  
2019 ◽  
Vol 24 (05) ◽  
pp. 2292-2307 ◽  
Author(s):  
Jizhou Tang ◽  
Kan Wu ◽  
Lihua Zuo ◽  
Lizhi Xiao ◽  
Sijie Sun ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Hydraulic Fracture ◽  
Fracture Propagation ◽  
Propagation Model ◽  
Rock Deformation ◽  
Hydraulic Fractures ◽  
Fracture Geometry ◽  
Fracture Width ◽  
Hydraulic Fracture Propagation ◽  
Fracture Height

Summary Weak bedding planes (BPs) that exist in many tight oil formations and shale–gas formations might strongly affect fracture–height growth during hydraulic–fracturing treatment. Few of the hydraulic–fracture–propagation models developed for unconventional reservoirs are capable of quantitatively estimating the fracture–height containment or predicting the fracture geometry under the influence of multiple BPs. In this paper, we introduce a coupled 3D hydraulic–fracture–propagation model considering the effects of BPs. In this model, a fully 3D displacement–discontinuity method (3D DDM) is used to model the rock deformation. The advantage of this approach is that it addresses both the mechanical interaction between hydraulic fractures and weak BPs in 3D space and the physical mechanism of slippage along weak BPs. Fluid flow governed by a finite–difference methodology considers the flow in both vertical fractures and opening BPs. An iterative algorithm is used to couple fluid flow and rock deformation. Comparison between the developed model and the Perkins–Kern–Nordgren (PKN) model showed good agreement. I–shaped fracture geometry and crossing–shaped fracture geometry were analyzed in this paper. From numerical investigations, we found that BPs cannot be opened if the difference between overburden stress and minimum horizontal stress is large and only shear displacements exist along the BPs, which damage the planes and thus greatly amplify their hydraulic conductivity. Moreover, sensitivity studies investigate the impact on fracture propagation of parameters such as pumping rate (PR), fluid viscosity, and Young's modulus (YM). We investigated the fracture width near the junction between a vertical fracture and the BPs, the latter including the tensile opening of BPs and shear–displacement discontinuities (SDDs) along them. SDDs along BPs increase at the beginning and then decrease at a distance from the junction. The width near the junctions, the opening of BPs, and SDDs along the planes are directly proportional to PR. Because viscosity increases, the width at a junction increases as do the SDDs. YM greatly influences the opening of BPs at a junction and the SDDs along the BPs. This model estimates the fracture–width distribution and the SDDs along the BPs near junctions between the fracture tip and BPs and enables the assessment of the PR required to ensure that the fracture width at junctions and along intersected BPs is sufficient for proppant transport.

Factor Analysis of Vertical Hydraulic Fracture Geometry in Coal Bed

2013 ◽  
Vol 316-317 ◽  
pp. 892-895 ◽  
Author(s):  
Bai Lie Wu ◽  
Yuan Fang Cheng ◽  
You Zhi Li ◽  
Peng Xu ◽  
Yu Ting Zhang
Keyword(s):  
Effective Means ◽  
Propagation Model ◽  
Coal Bed ◽  
Vertical Wells ◽  
Differential Stress ◽  
Fracture Geometry ◽  
Fracture Length ◽  
Treatment Conditions ◽  
Pump Rate ◽  
Fracture Height

Hydraulic fracturing is one of the effective means to enhance coal bed methane production for vertical wells. This paper presents an approach that uses pseudo-3D fracture propagation model to study the influence of petrophysical properties, differential stress, treatment conditions, etc. on fracture geometry. It is shown that differential stress, pump rate is proportional to fracture length and width; elastic modulus, Poisson`s ratio, pump rate, etc. is proportional to fracture height. The finding is of great importance for acquiring ideal fracture geometry.

Hydraulic Fracture Height Growth Containment by Artificial Barrier: Experimental Studies

2011 ◽  
Vol 396-398 ◽  
pp. 2420-2423 ◽  
Author(s):  
Yong Quan Hu ◽  
Jin Zhou Zhao ◽  
Tao Lin
Keyword(s):  
Hydraulic Fracture ◽  
Experimental Studies ◽  
Petroleum Industry ◽  
Current Treatment ◽  
Height Growth ◽  
Influential Factors ◽  
Fluid Viscosity ◽  
Core Flow ◽  
Flow Test ◽  
Fracture Height

It is necessary to control hydraulic fracture height growth by creating artificial barrier for reservoir with thin payzone or weak overburdens and underburdens. In this paper, the influential factors on resistance role of artificial barrier were firstly identified and the parameters value range was determined. Then, an affixing intermediate container was combined into the core flow test device in order to ensure buoyant diverter well dispersed into carrying fluid in experiment test, and the particle size distribution of buoyant additives was tested by Malvern laser counter. The crack was made about 2/3 length in artificial core for simulating artificial barrier process by core flow test which were accomplished in base of recommendation practice of petroleum industry. Lastly, successive regression method was applied and a statistical relationship of the barrier strength with carrying fluid viscosity, floating additives concentration and core permeability. Then scouring experiments are made under modeling hydraulically fracturing treatment conditions. It was proven that the artificial barrier was steady at current treatment parameters and that could be effectively controlled hydraulic fracture height growth.

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