Production Response From Southeastern New Mexico Morrow Wells Stimulated with Binary Foams

Abstract

For many years, local industry consensus and various authors1,2,3 have concluded that with few exceptions4, fracture-stimulation of the Morrow sand series in southeastern New Mexico is best undertaken utilizing fluids containing [at least] CO2, KCl, and methanol. Unfortunately, this conclusion originates from hearsay and limited studies that looked at only a few treatments. Difficulties with past efforts to verify and compare post-fracture well performance were centered on the inability to database naturally-occurring parameters for the majority of wells, as well as problems stemming from inaccurate and erroneous public data. Localized successes with foams containing CO2, KCl, nitrogen, and methanol prompted a more comprehensive study of the area that attempted to address the problems associated with the evaluation of public production data. A Graphical Information System5 was coupled with publicly available production data and internal pumping service company records6 to attempt to determine if one completion methodology was really any better than another. Production from wells treated with Binary foams over a four-year period (1996 - 1999) was compared to production from up to 19 offsets per well of interest. A set of relatively rigid criteria was set up and followed to ensure that the study was as objective as possible, given the constraints of working with public data. Although it was not possible to "normalize" the wells of interest or their offsets to account for differences in natural parameters, the large number of wells examined provided some degree of confidence in the validity of the process. Conclusions are presented. The average first 90-day cumulative production from wells treated with Binary foam was higher than the average of wells that were stimulated with other systems. Evidence is also presented to suggest that it may be prudent to fracture-stimulate wells with high initial natural production. Introduction The Morrow formation in southeastern New Mexico is a Pennsylvanian gas sand that can be relatively prolific in certain areas of Chaves, Lea and Eddy Counties. Reserve estimates are in excess of 10 trillion cubic feet of gas and about 100 million barrels of oil and/or condensate1. Complex vertical sequences of sandstone reservoirs are present that can vary substantially, due to the lateral shifting of the various high-energy depositional environments over time. Siliciclastics originating from the Pedernal uplift in the northwest and Central Basin platform to the east were deposited in channels and along a rapidly shifting shoreline.7 Over time, trapping of mobile fluids was accomplished by lower-energy deposition of Atoka and Strawn sediments. Productive hydrocarbon traps are typically from permeability pinchouts within alluvial plains, transitional marine, channel, and shoreline facies. Variability of the Morrow can be illustrated in several ways. Formation depths range from 8,000 to 15,000 feet across the three-county area. Net zone thickness can be from just a few feet to as high as 50 feet or more, and can be present multiple times in a complex vertical series of facies.Individual wells can have several distinct zones in which each zone originated from a unique deposition. Productive resevoir porosities have ranged from 4 to 15%. Permeabilities of producing zones have been reported from hundreths of a millidarcy to several hundred millidarcies. Pressure gradients can range from underpressured reservoirs at 0.3 psi/ft to overpressured sands at 0.6 psi/ft8. Morrow sands can be described as well consolidated, white angular to sub-angular, coarse grains containing various quantities of calcareous and glauconitic material. X-Ray diffraction and SEM analysis on sidewall and full cores have revealed typical mineral content8 from the major mineral types as follows:Quartz content from 45% to 98%Carbonate content from 8 to 48%Feldspar content from 2 to 15%Clay content from 0.5 to 28%

Experimental Research on Proppant Transport Performance of GRF-CO₂ Fracturing Fluid

“…Poor regained conductivity of crosslinked polymer-base fluids has been shown to decrease effective halflength and production. 7 Attempts have been made to remove the polymer completely. Previous polymer alternatives have consisted of 100% CO 2 , 8 a CO 2 /N 2 mix, 7 and VES-base systems.Each attempt has involved complications.…”

“…7 Attempts have been made to remove the polymer completely. Previous polymer alternatives have consisted of 100% CO 2 , 8 a CO 2 /N 2 mix, 7 and VES-base systems.Each attempt has involved complications. The new system contains a combination of surfactants with different functional groups.…”

Fracture Stimulation Utilizing a Viscoelastic-Surfactant-Based System in the Morrow Sands in Southeast New Mexico

“…In the recent past, several papers [1][2][3][4][5][6][7][8][9] have been written about stimulation practices in the SENM Morrow. These formations of Pennsylvanian age are deposited erratically on the Northwest Shelf of the Delaware Basin, with the most prolific hydrocarbon bearing region lying largely in the Southeastern part of Chaves County, Western part of Lea County and the remaining occupying most of the Eddy County, as shown by the shaded region of Fig.…”

Utilizing Flowing Pressure-Transient and Mass-Balance Analysis of SENM Morrow Producers To Calibrate 3D Hydraulic-Fracture Modeling – A Case History

“…The literature pertaining to stimulation of southeastern New Mexico Morrow reservoirs is extensive 1,2,3,4,5,6,7,8 . Observations related to stimulation process are abundant, but there is a distinct shortage of guidance pertaining to maximization of NPV by optimizing treatment sizing in this formation.…”