Multi-Well Experiment: A Field Laboratory for Tight Gas Sands

Abstract

The Multi-Well Experiment (HWX) is a researchoriented field laboratory whose objective is develop the understanding and technology to allow economic production of the several years supply of natural gas estimated to be within the low permeability, lenticular gas sands of the Western United States. Features of MWX include:(1) close-spaced wells (~125 ft,~38 m) for reservoir characterization, interference testing, wellto-well geophysical profiling, and placement of diagnostic instrumentation adjacent to the fracture treatment; (2) complete core taken through the formations of interest: (3) a comprehensive core analysis program; (4) an extensive logging program with conventional and experimental logs; (5) determination of in situ stresses in sands and bounding shales: (6) use of various seismic surveys and sedimentological analyses to determine lens morphology and extent; (7) use of seismic, electrical potential and tilt diagnostic techniques for hydraulic fracture characterization: and (8) a series of stimulation experiments addressing key questions. This paper presents the current MWX accomplishments in the above areas since drilling started at the site in September 1981 through December 1982.

A Viscoelastic Constitutive Model for Determining In-Situ Stress Magnitudes From Anelastic Strain Recovery of Core

“…Other examples from the MWX 23 Table 3, along with a comparison with the direct model. Notice that the difference between the two horizontal stresses is now only 600 psi [4.1 MPa], as opposed to 800 psi [5.5 MPa] in the deeper Rollins sandstone.…”

“…A constant value for Poisson's ratio in our analysis would partition the creep compliances according to ]2=]1(1-2p.)/(1+p.) ............................ (23). for tl =t2' Previous results showing the uncertainty in many of the dilatational mechanisms help us understand why the direct model does not give good results for many cases, such as those with contraction.A negative point associated with the present technique is the questionable validity of the fit for noisy or late-starting data sets.…”

Fracture Diagnostics Results for the First Multiwell Experiment's Paludal Zone Stimulation

“…2 Objectives of the field laboratory are to characterize lenticular gas-sands reservoirs and to evaluate technology for their production. A series of stimulation experiments has been planned to provide the data required to meet these objectives.…”

Insights Into Natural Gas Production From Low-Permeability Reservoirs

“…4. The fluvial interval ( 4, 400 to 6, 000 ft ( 1340-1830 m)) consists of irregularly shaped, multistory, composite sandstones which were deposited ,by broad, meandering stream systems.…”