A Novel Algorithm for Transforming Real-Time and Post-Drill Geothermal Drilling Data into Geologically and Commercially Applicable Outputs

Abstract This paper presents a new set of algorithms and methodologies that use real-time drilling rig measurements, and transforming them into near real-time, geologically applicable analytical results. Our approach to drilling data makes rapid, direct use of the raw rig data to produce analytical results. Results will describe petrophysical, geological, and geomechanical properties of the drilled section, identify zones that are favorable for geothermal development and provide correlative context within the broader geothermal region, or the immediate prospect area. We present an integrated, automated analysis workflow that can be performed in real-time, where collected data populate templates while drilling (every ft to 90 ft.). This workflow significantly improves the geosteering and wellbore placement, reduces uncertainty, and provides near wellbore rock characterization which is used for completion optimization. Several steps should be executed before data interpretation. Steps are: (1) importing Pilot Hole (PH) and Drilling Well (DW) wellhead data information, (2) developing high level well log analysis including correlating PH original Gamma Ray (GR) and generates DW synthetic GR gamma-ray from Mechanical Specific Energy (MSE) data, (3) obtaining higher than 85% correlation coefficient and rocks classification, (4) constructing lithology percentage pie-chart, K-mean clustering, visualizing gas compound (CO2, H2S, and CH4), (5) plotting chlorite and epidote as indication of weathered products, if available, and (6) identification of potential fracture intervals, based on several drilling data parameters. The workflow has been tested and proved on public well data from Department of Energy (DoE), State database repository (from several states where data were available to public). Valuable information volumes are captured which are not normally pinpointed due to constraints on data collection technologies, cost reduction measures, limitations of current and universal data reporting format, and lack of specific geothermal tools due to the high temperature environment. Testing resulted in identifying lithologies based on igneous and metamorphic minerals properties, geo-mechanical properties and issues, potential geothermal fractured and producing intervals, out-of-target intervals, and potential dike crossing identification. Interpretation of all drilling data and plots including distribution of epidote and chlorite as weathering product in fracture areas, DT variation (if data become available), temperature and pore pressure, synthetic GR and MSE, mud gain/loss, CO2 content increase, assists in defining potential fractured intervals which will assist completion engineers’ decision-making process. The implementation of this methodology leads to: Cost saving regarding the need of additional tools and surveying equipment.Lowering risks and uncertainty and increasing cost-effectiveness by reducing possible errors in selection of potential production intervals.Increasing confidence in wellbore placement and time and cost savings regarding to the data validation, reservoir characterization, and identification of potential zone with sufficient water volume for generation of heat.Promoting increased efficiency in the selection of completion procedure, if required.Reduction of potential well interferences when completing neighboring wells.Cost saving regarding availability of data and interpretation while drilling a geothermal well, and elimination of additional surveying tools.