System and method for determining a probability of well success using stochastic inversion
Inventors
Trainor-Guitton, Whitney • Hoversten, Gary Michael
Assignees
Chevron USA Inc • Lawrence Livermore National Security LLC • Lawrence Livermore National Laboratory LLC
Publication Number
US-9183182-B2
Publication Date
2015-11-10
Expiration Date
2032-08-31
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Abstract
A system and a computer implemented method for determining a best well location from a plurality of possible well locations are described herein. The method includes drawing a plurality of earth models from a posterior distribution, wherein the posterior distribution is generated by stochastic inversion of existing data; calculating a well production at a plurality of proposed well locations within an earth model in the plurality of earth models using a relationship between the well production and earth parameters; calculating from the plurality of earth models, cost distributions using the relationship between well cost and the earth parameters; and calculating probability weighted values for the proposed well locations using probabilities from location dependent stochastic inversions as weights.
Core Innovation
The invention provides a computer implemented method and system for determining a best well location from a plurality of possible well locations by drawing a plurality of earth models from a posterior distribution generated by stochastic inversion of existing data. This posterior distribution reflects a probabilistic characterization of earth parameters such as electrical resistivity, permeability, density, porosity, and depth, based on geophysical, geochemical, or geological data.
The method calculates well production at each proposed well location using a relationship between well production and earth parameters, calculates cost distributions using a relationship between well cost and earth parameters, and then calculates probability weighted values combining these factors using probabilities from location dependent stochastic inversions as weights. The location with the maximum weighted value signifies the best well location.
The problem addressed is that conventional methods to determine well success and value of information either rely on subjective statistics or non-physics based statistics unrelated to the physics of rock formation, potentially leading to erroneous estimates of well success probabilities. There is a need for an improved quantitative approach that replaces subjective risk assessment with stochastic inversion based parameters to better guide well placement decisions and optimize outcomes.
Claims Coverage
The patent includes multiple claims, with two independent claims directed to a computer implemented method and a computer system for determining a best well location from multiple possibilities using stochastic inversion generated posterior distributions.
Computer implemented method for selecting best well location using stochastic inversion
Drawing multiple earth models from a posterior distribution generated by stochastic inversion of measured geophysical, geochemical or geological data; calculating well production at proposed well locations using a relationship between production and earth parameters; calculating cost distributions from earth parameters; calculating probability weighted values for well locations using probabilities from location-dependent stochastic inversions; finally determining best well location based on these calculated weighted values.
Computer system configured to implement the method using stored data and processing
A computer system comprising readable memory that stores well locations and existing measured data and a processor configured to draw earth models from a stochastic inversion generated posterior distribution; calculate well production and cost distributions using relationships to earth parameters; calculate probability weighted values for proposed well locations using location dependent inversion probabilities; and determine the best well location based on the weighted values.
The independent claims cover the core innovation of using stochastic inversion to generate probabilistic earth models and employing these models to calculate production, cost, and probability-weighted values over possible well locations to select the best location, implemented as both a computer method and a computer system.
Stated Advantages
Provides a quantitative, physics-based approach to assess risk and determine well success probabilities, avoiding subjective or non-physical statistics.
Improves decision making by incorporating stochastic inversion derived posterior distributions of earth parameters, enhancing reliability in well location selection.
Enables calculation of probability weighted values that integrate production and cost uncertainties, yielding an expected value to optimize well placement.
Supports calculation of Value of Information (VOI) to estimate how additional data acquisition can improve decision outcomes.
Documented Applications
Determining the best well location for oil, gas, or geothermal wells based on probabilistic analysis of earth properties.
Evaluating Value of Information (VOI) to decide on the acquisition of new geophysical data to improve well success probability.
Using geophysical data such as seismic, magnetotelluric, controlled source electromagnetic data, or production data from wells to generate earth models.
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