A Coordinated Seismic Study of the Multi-Well Experiment Site

Lee, M.W.; Miller, J.J.; Albright, James N.; Fried, Jonathan; Applegate, James K.

doi:10.2118/11613-ms

Cited by 3 publications

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“…The MWX site velocity data had been determined from previous seismic surveys. 13 However, the paludal zone is so lithologically complex that the seismic velocities of the medium were extremely variable with depth. Extrapolating these data over the region of interest could have potentially resulted in large inaccuracies.…”

Section: Microseismic Eventsmentioning

confidence: 99%

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

Hart

Engi

1987

SPE Formation Evaluation

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A dual seismic system designed to monitor the growth of hydrofractures was fielded during the first stimulation at the U.S. DOE-sponsored Multiwell Experiment (MWX) during Dec. 1983. The MWX consists of three 8,OOO-ft [2438-m] wells drilled in low-permeability gas reservoirs. The wellbores are spaced less than 200 ft [61 m] apart over most of their length. With this configuration, microseismic activity created by the fracture treatment in one well could be observed with downhole geophone packages in the two adjacent wells.Responses of the two triaxial borehole seismic tools (BST's) were monitored in real time. Upon detection of a seismic event of known location, orientations of the BST's were determined from the polarization of the compressional wave arrivals. From knowledge of the horizontal and vertical angles of incidence and an empirical estimate of seismic velocities, the locations of the fracture-induced seismic sources were estimated. Thus the location of the microseisms could be estimated and, in turn, the fracture height and extent inferred.This paper presents the results of fracture diagnostics by use of this borehole seismic system for the first MWX stimulation. This information is compared and combined with the results obtained from other diagnostic techniques to provide an integrated estimate of the fracture geometry resulting from the stimulation.

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Section: Microseismic Eventsmentioning

confidence: 99%

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

Hart

Engi

1987

SPE Formation Evaluation

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A Comprehensive Fracture Diagnostics Instrumentation Fielding Program

Hart

Engi

Morris

1983

SPE/DOE Low Permeability Gas Reservoirs Symposium

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Economic development of low permeability gas reservoirs often necessitates the use of massive hydraulic fracturing. Assessment of the effectiveness of the induced fracture requires knowledge of the dimensions, orientation, and spatial characteristics of the fracture in relation to the gas-bearing formation. A comprehensive characterization of fracture propagation not only aids in fracture treatment design for the reservoir, but can also help specify well spacings which will minimize interference of drainage patterns and thus maximize economic-recovery potential. This paper presents an approach to the development of a comprehensive fracture diagnostics program. The fracture diagnostics subprogram for the Multi-Well Stimulation Experiment is discussed in detail, including fielding descriptions and operational procedures. Synopses of measurement techniques are given with emphasis on the fracture parameters one would expect to estimate from the individual instrumentation systems. Introduction The National Petroleum Council estimates that there are 924 trillion cubic feet [262 × 10(11) m3] of gas in place in the U.S. tight gas basins. Historically, tight gas fields have been uneconomical and inefficient to produce due to the low natural flow rates of the gas. With the introduction of massive hydraulic fracturing, the outlook for increased production from blanket (continuous) formations has improved. However, current fracturing technology applied to lenticular tight gas reservoirs, containing more than 40 percent of the estimated recoverable tight gas, has been disappointing. A Multi-Well Experiment (MWX) has been conceived to address the uncertainties concerning production of the lenticular tight gas resource. The MWX site is in the Rulison field in the Piceance Basin of Colorado. The formation of interest lies Piceance Basin of Colorado. The formation of interest lies between 3900 and 8300 ft (1190 and 2530 m). Lenticular sands constitute most of this interval with continuous blanket sandstones at the base of the column. Two closely-spaced wells, a stimulation-production well and an offset well for stress and interference testing and diagnostics, have been completed through the interval. The two wells are approximately 110 ft. (34 m) apart. Stimulation Experiment I (SX-1) may be conducted in the blanket Cozzette formation which lies at a depth of approximately 7800 to 8000 ft (2380 to 2440 m). One goal of this first experiment is to characterize the hydraulic fracture geometry. In order to provide a data base from which the geometry of the propagating fracture can be inferred, a number of geophysical propagating fracture can be inferred, a number of geophysical diagnostic techniques, which either exist commercially or are under development and testing, will be fielded. These techniques include the use of (1) passive borehole and surface microseismic techniques, (2) a surface electrical potential system, (3) tiltmeters, (4) surface and downhole pressure probes, (5) temperature logs, and (6) radiation logs. The fracture geometry parameters to be estimated from this instrumentation suite are parameters to be estimated from this instrumentation suite are fracture azimuth, height, length, and asymmetry. TECHNIQUE DESCRIPTIONS BOREHOLE SEISMIC Fracture azimuth, height, and extent during the initial stages of stimulation can be inferred from seismic signals received during non-proppant pumping times. The seismic events are thought to be caused by shear fractures induced by high pore fluid pressure occurring on planes of weakness in the rock surrounding the large hydraulic fracture. p. 461

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A Coordinated Seismic Study of the Multi-Well Experiment Site

Cited by 3 publications

References 0 publications

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

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

A Comprehensive Fracture Diagnostics Instrumentation Fielding Program

Delineation of lenticular-type sand bodies by the vertical seismic profiling method

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