D. Nathan Meehan | Stanford University (original) (raw)

Papers by D. Nathan Meehan

A number of developments over the past five years have led to dramatic change in the design and e... more A number of developments over the past five years have led to
dramatic change in the design and execution of hydraulic
fracturing treatments. Five primary new issues are described
convection, tortuosity, rock/fracture (non-linear) response,
appropriate use of rheology/flow-rate and permeability variation
effects. Consequences include“paradigm shifts”,such as inverse
relations between appropriate proppant concentration and reservoir
permeability. Resulting integrated cost-effective and rewarding
methodologies for fracture execution are emphasized and the
methodology is illustrated with just a few case-studies,selected to
emphasize a variety of technical features as against absolutely
optimum execution.

A study evaluating the impact of injecting a fluid capable of complete immobilization of certain ... more A study evaluating the impact of injecting a fluid capable of complete immobilization of certain swept portions of the reservoir. Large flooding pressure increases were observed.

At the bottom of the current industry downturn the SPE President reflects on the state of the ind... more At the bottom of the current industry downturn the SPE President reflects on the state of the industry and what can be done to weather the storm....or survive the ice age. Steps SPE has taken include downsizing, focusing activities, using some of the "rainy day" fund and focusing on helping unemployed members.

Petroleum engineering and geology students, young and even seasoned professionals in the industry... more Petroleum engineering and geology students, young and even seasoned professionals in the industry question the long-term viability of the industry. Career options and opportunities are discussed within the framework of the value of oil and gas to improving people's lives.

SPE 22704 Horizontal wells have been applied in many types of reservoir conditions with a variety... more SPE 22704 Horizontal wells have been applied in many types of
reservoir conditions with a variety of applications. The
most successful of these has been exploiting the very
large horizontal permeability anisotropies associated with
naturally fractured reservoirs. Log analysis has always
been difficult in naturally fractured reservoirs; very little
has been published regarding horizontal well logs. This
paper summarizes Union Pacific Resources (UPRC)
experience logging dozens of horizontal wells in several
different naturally fractured reservoirs, summarizes the
improved information resulting from this experience,
contrasts various well logs applicable in such areas, and
describes a method for categorizing fracture apertures
used to quantify the total horizontal well fracture index
(RFI).

Despite progress made in recent years and efforts of the World Bank-led Global Gas Flaring Reduct... more Despite progress made in recent years and efforts of the World Bank-led Global Gas Flaring Reduction Partnership (GGFR), flaring of natural gas continues to be an environmental challenge and a waste of resources. By some estimates, as much as 3.5% of global gas production is flared or vented. In addition to wasting a non-renewable, marketable resource, flaring and venting represent a major source of avoidable CO2 and CH4 emissions that emit excessive amounts of greenhouse gas with no offsetting benefits. In the first half of 2016, Nigeria flared over 3 billion cubic meters (Bcm) (106 Bcf) of gas, with a nominal value of some US$300 MM. Excuses for flaring and venting include the costs of gathering, processing and treating gas, and the lack of infrastructure and access to funds to develop and deliver the gas into viable markets. Some financial terms for Production Sharing Contracts (PSCs) or other contracts, and low regulated gas prices, fail to properly encourage gas use. Sour gas or gas with high levels of non-hydrocarbon diluents, though not applicable to Nigerian gas, further complicates commercialization. A lack of collaboration between operators and regulators also contributes to improper development planning. Retrofitting costs and mature fields further complicate gas use. The potential to monetize an ever increasing portion of flare gas in Nigeria has many positive benefits, including improving the environment for those living in proximity to oil and gas operations; both savings and new revenues for project sponsors; greater certainty for lenders, and the potential substitution of expensive and polluting diesel-powered applications. Flaring and venting gas should be infrequent, brief and efficient. This paper presents a variety of ways to monetize small to medium volumes of gas, along with ways to minimize flared and vented gas. The relative volumes of gas required for a wide range of applications are reviewed, including distributed power, CNG, methanol or other GTL, mini-and micro-LNG, and other emerging technologies.

Naturally fractured reservoirs are the most significant target for horizontal wells in the U. S. ... more Naturally fractured reservoirs are the most significant
target for horizontal wells in the U. S. While most of the
horizontal wells drilled to exploit naturally fractured
reservoirs are not logged. substantial useful information
can be obtained by logging such wells. A previous
paper! contrasted various logging technologies including
acoustic televiewers. sonic logs, and oriented
microresistivity devices. Union Pacific Resources (UPRC)
has logged 42 of the 120 horizontal wells drilled to date;
38 of these wells have been logged with Schlumberger's
Formation MicroScanner (FMS), an oriented
microresistivity device. Extensive analysis of these logs
on UNIX-based workstations and correlation with
horizontal well performance has resulted in a correlation
between the horizontal well fracture index (RFI) and
horizontal well fluid Productivity Index (PI). Attempts to
correlate RFI with ultimate oil or oil and gas recoveries
have been unsuccessful; however. a correlation with
ultimate fluid (oil+water) recoveries has been developed.
These correlations have been used to integrate FMS
infonnation with artificial lift. stimulation, isolation, and
repair decisions as well. Example cases are used to
illustrate these decisions. Further. the quantified data
have been used in making development. exploitation, and
spacing decisions. Geostatistical techniques used in
reservoir characterization efforts have also incorporated
the spatial distribution and correlation of RFI density.

In the SPE President's column, #SPEcares is introduced as the hashtag for volunteer and humanitar... more In the SPE President's column, #SPEcares is introduced as the hashtag for volunteer and humanitarian activity within the society. The history of philanthropy and humanitarian activity in oil and gas is discussed.

There are two great truths tied to hydraulic fracturing. 1. It has helped improve people’s lives ... more There are two great truths tied to hydraulic
fracturing.
1. It has helped improve people’s lives
by enabling the oil and gas industry to tap
reserves that otherwise could not have
been recovered.
2. It has unleashed dramatic public
opposition.

The case for hydraulic fracturing to improve people's lives is put forth

$Research paper thumbnail of Waterfracs – Results from 50 Cotton Valley Wells$

TX 75083-3836, U. S.A., fax 01-972-952-9435. difficult to evaluate fracture quality in the short ... more TX 75083-3836, U. S.A., fax 01-972-952-9435. difficult to evaluate fracture quality in the short term since detailed prefrac and postfrac well testing are rarely performed in this formation. Active operators will have completed many wells before being able to fulIy evaluate the effect of fracture design changes. This paper presents the most current and comprehensive waterfrac production data available and updates the production. We believe that there are several possibilities of why waterfracs are successful. Abstract In previous publications' " z we showed that several fracture treatments using treated water and very low proppant concentrations (waterfracs) were very successful in the East Texas Cotton Valley sandstone. This paper expands on the production examples with a more comprehensive set of production comparisons of wells completed with standard fracture treatments and waterfracs since 1995. The data sets are from three different Cotton Valley fields and include approximately 50 waterfrac treatments.

Union Pacific Resources Co. (UPRC) is a large independent operator with about 100 petroleum engin... more Union Pacific Resources Co. (UPRC) is a large independent operator
with about 100 petroleum engineers. UPRC has a reasonably
sophisticated PC network with many hundreds of PC's connected
by several local area network (LAN) servers. Essentially all engineers
have a 386-based PC on their desks with access to a host of
software packages, peripheral devices, and mainframe computers.
Many engineers have acquired 486-based PC's. UPRC's solution
has involved migrating from a DOS-based platform on individual
users' desks to UNIX workstations. Dozens of UNIX workstations
are networked; some are "on the desk," while others are located
in central locations. Reservoir simulation, geostatistical modeling,
image processing, and log analysis are now done exclusively on
the UNIX workstations. Numerous DOS-based programs, however.
have not yet been migrated into the UNIX environment.
This paper describes the topography of both PC DOS and UNIX
workstation networks in UPRC and examines the flow of information
in each network configuration to identify differences. The successes
and failures of various techniques for providing access to
both platforms are presented.

A review of nanotechnology applications for oil and gas with examples. The potential impact on ec... more A review of nanotechnology applications for oil and gas with examples. The potential impact on economics.

This paper presents techniques for the design and analysis of interference tests when both the ac... more This paper presents techniques for the design and analysis of interference tests when both the active and observation well are intercepted by hydraulic fractures. These techniques. are based on new mathematical solutions. The solution is general for any values of dimensionless fracture conductivity including infinite conductivity. The solution is presented in Laplace space; fracture skin, wellbore storage, naturally fissured matrix behavior, etc. are readily included.

A discussion of HSE aspects of oil and gas including the concept of the perfect day.

A discussion of the role petroleum engineers can and should play in making oil and gas developmen... more A discussion of the role petroleum engineers can and should play in making oil and gas development and production more sustainable.

A comparison of hydraulic fracture performance over the history of the Moxa Arch development. Res... more A comparison of hydraulic fracture performance over the history of the Moxa Arch development. Results from 200+ treatments coupled with 3D modeling shows impact of varying proppant and fluid selection.

Cubic equations-of-state (EOS) mathematically relate pressure, volume, and temperature. These equ... more Cubic equations-of-state (EOS) mathematically relate pressure, volume, and temperature. These equations describe the volumetric and phase behavior of single components and mixtures requiring only the critical properties and acentric factor of each component including the plus-fraction. For pure compounds, the required properties are well defined; however, nearly all naturally occurring gas and crude oil fluids contain heavy fractions that are not well defined. These heavy plus-fractions are mixtures of hundreds of paraffinic, naphthenic, aromatic, and other organic compounds that cannot be discretely identified and described. These heavy fractions are often lumped together and called the " plus-fraction " (e.g. C 7+ fractions). Adequately characterizing these undefined plus fractions in terms of their critical properties and acentric factors has been long recognized as a challenge in compositional analysis using EOS models. Changing the characterization of the plus fraction can have a significant impact on the volumetric and phase behavior of a hydrocarbon mixture predicted by EOS models. In applying EOS in compositional modeling and PVT analysis, empirical correlations are used to estimate critical properties and acentric factors of the plus-fractions. Coefficients for these empirical expressions were generated by matching critical properties of pure components; however, the applications of these empirical relationships are extended to estimate the critical properties the plus-fractions. This paper presents a practical approach for calculating EOS parameters " a, b, and α " of the plus-fraction from its readily available measured physical properties, i.e., molecular weight " M " and specific gravity " γ ". Our objective is to improve the predictive capability of EOS models. A new model was developed based on the Peng-Robinson Equation of State " PR EOS " and with the modification as outlined in this paper. The predictive capability of the modified PR EOS is displayed by matching a set of laboratory data on several crude oil and gas-condensate systems. Performance of the proposed method was also compared with predictive PVT results generated by two commercial compositional simulation models. Additional validations were made by comparing results from applying the proposed approach with those of Coats and Smart 4 regression methodology with PR EOS.

Historically, petroleum engineers have neglected the role of the physical porous medium except fo... more Historically, petroleum engineers have neglected the role of the physical porous medium except for its storage properties (porosity, thickness, areal extent) and its delivery capabilities (permeability, natural fractures, susceptibility to damage). Engineers charged with maximizing hydrocarbon recovery address rock mechanics issues only of dire necessity and then with little enthusiasm. Rock stresses and failure criteria are the most critical aspects of rock engineering for petroleum engineers. Horizontal drilling has presented a host of new issues that are more pervasive than are vertical well issues. This paper addresses several areas, including: • an overview of rock mechanics issues of importance to petroleum engineers, • a discussion of typical stress magnitude measurements routinely used, • a brief review of stress orientation and • a discussion of the rock mechanics issues critical to horizontal wells.

This paper presents a semianalytical model for transient flow into multiple vertical wells produc... more This paper presents a semianalytical model for transient flow into multiple vertical wells producing from a porous medium containing randomly distributed discrete fractures. Both vertical openhole wells and hydraulically fractured vertical wells are considered. The semianalytical model simulates pressure and pressure-derivative characteristics of wells and flow distribution along and through both the natural and the hydraulic fractures. The study shows that single or multiple isolated natural fractures yield negative pseudoskin factors in vertical wells near isolated fractures. The negative pseudoskin factor is a function of fracture conductivity, density, length, distance from the wellbore, and azimuth. Using the model, we demonstrate that the shape of the pressure derivative is related to fracture distribution. The results of this study indicate that the conventional double-porosity analysis to predict the storativity ratio of a naturally fractured system is not reliable. Also, the displacement between two semilog straight lines is not necessarily a good indicator of the storativity ratio. Introduction The main objective in this study is to develop a semianalytical model to simulate the flow inside a homogenous porous medium containing randomly distributed and unconnected fractures. Once such a model is available, the effect of isolated fractures on the pressure-transient behavior of producing wells may be investigated. In the current literature, only a few analytical studies focus on the effect of stochastically distributed natural fractures on well performance. To the best of our knowledge, the literature lacks a model to simulate the transient flow toward a system of vertical open holes and hydraulically fractured wells producing from a porous medium dissected by randomly distributed but disjointed natural fractures. This study offers such a model.

So called "water-fracs" have obtained excellent results in the Austin Chalk formation of Giddings... more So called "water-fracs" have obtained excellent results in the Austin Chalk formation of Giddings field. This inexpensive treatment uses high volumes of water but no proppant. The reasons the treatment is successful include imbibition, gravity drainage, skin damage removal , and repressurization of the reservoir to enhance recovery. Union Pacific Resources Co. (UPRC) has treated about 2S0 vertical and ISO horizontal wells with very high economic success rates. Incremental recoveries from horizontal well water fracs alone exceed S million bbl of oil equivalent (6 Mcf = 1 bbl).

The case for hydraulic fracturing to improve people's lives is put forth

$Research paper thumbnail of Waterfracs – Results from 50 Cotton Valley Wells$

A discussion of HSE aspects of oil and gas including the concept of the perfect day.