Showing papers by "Pioneer Natural Resources published in 2019"

Monitoring horizontal well hydraulic stimulations and geomechanical deformation processes in the unconventional shales of the Midland Basin using fiber-based time-lapse VSPs, microseismic, and strain data

Abstract: A variety of methods are utilized in an instrumented vertical wellbore to invert for and estimate the heights and lateral extents of the hydraulic fracture treatment. Data were acquired wi...

Rate-Transient Analysis Based on the Power-Law Behavior for Permian Wells

Abstract: In unconventional reservoirs, the application of many rate–transient–analysis (RTA) techniques relies heavily on the identification and analysis of the linear flow regime, which is characterized by a ½–slope on a log–log plot of Δp vs. t. Through our analysis of more than 400 wells with downhole pressure gauges in the Wolfcamp Shale of the Permian Basin, we observed power–law behavior, but with slopes much different from ½ over long periods of time. In many cases, the duration of the straight line with a slope different from ½ lasts for years, without ever converging to ½. In some cases, the slope changes over time but is rarely the characteristic ½–slope observed over long periods. Rate forecasts would be in error if we were to assume that the slope would converge to a ½–slope at a later time. In this work, we present examples of Permian Wolfcamp horizontal wells each with a measured bottomhole pressure (BHP) to demonstrate the characteristic power–law behavior with slopes different from ½. Power–law behaviors are typical in heterogeneous systems and are identified using the Chow pressure group (CPG). On the basis of the concept of power–law behavior, we developed a workflow to analyze single–phase rate–transient data with high–quality measured BHP. Ultimately, the new workflow for RTA uses power–law characteristics to evaluate well performance and is a complementary tool to traditional methods such as the Arps decline–curve analysis (Arps 1945). In this paper, we outline a power–law analysis workflow scheme and demonstrate that the CPG is a convenient means for identifying the exponents of straight lines. In addition, we present case studies to demonstrate the application of this technique to predict the long–term well performance from choked–back wells, to evaluate long–term performance changes associated with offset fracture hits, and to estimate the hyperbolic–decline–curve b–factor.

Machine learning regressors and their metrics to predict synthetic sonic and mechanical properties

Abstract: Planning and optimizing completion design for hydraulic fracturing require a quantifiable understanding of the spatial distribution of the brittleness of the rock and other geomechanical pr...

Method for predicting drill bit wear

Abstract: A system for improving drill bit performance, comprising processors and memory storing instructions to obtain a wear report for a drill bit, wherein the wear report includes wear characteristics of the drill bit and drill operating parameters under which the drill bit was used; compare the wear characteristics of the drill bit to a threshold for acceptable drill bit wear; and adjust drill operating parameters based on the wear characteristics of the drill bit. The instructions to obtain the wear report for the drill bit include instructions to analyze images of the drill bit to identify wear characteristics; identify wear patterns based on the wear characteristics of the drill bit; identify probable drilling conditions based on the wear patterns; and generate the wear report for the drill bit based on the images of the drill bit, the wear characteristics of the drill bit, and the probable drilling conditions.

High resolution seismic data derived from pre-stack inversion and machine learning

Abstract: A system and method combines model-based inversion and supervised neural networks to develop high resolution rock property volumes from surface seismic data. These volumes have higher frequency and are calibrated to fit well log data. In addition to rock volumes, a Reflection Coefficient (RC) volume is derived from the acoustic impedance volume. The RC volume has much higher frequency, better lateral continuity, and ties to the well logs better than conventional seismic or frequency enhanced data. By interpreting and mapping with this RC volume, a much more accurate depth model can be built, which allows for a horizontal well to be accurately drilled.

Reduced emissions method of cleaning hydrocarbon separator and storage tanks

Abstract: A method for cleaning a storage tank, comprising isolating the tank; creating a vortex within the tank by pumping fluid through one or more nozzles disposed within the tank, thereby dislodging sediment within the tank; and connecting a suction source to a drain located on a bottom of the tank, thereby removing the fluid and sediment without exposure to air. Each nozzle may comprise one or more sub-nozzles positioned to direct fluid flow to assist in creation of the vortex and removal of the fluid and sediment. A storage tank, comprising one or more nozzles disposed within the tank such that fluid may be pumped through the nozzles to create a vortex within the tank; and a drain line located on a bottom of the tank such that a suction source may be connected and contents of the tank removed without exposure to air.