A fast forward algorithm for real-time geosteering of azimuthal gamma-ray logging.

Geosteering is an effective method to increase the reservoir drilling rate in horizontal wells. Based on the features of an azimuthal gamma-ray logging tool and strata spatial location, a fast forward calculation method of azimuthal gamma-ray logging is deduced by using the natural gamma ray distribution equation in formation. The response characteristics of azimuthal gamma-ray logging while drilling in the layered formation models with different thickness and position are simulated and summarized by using the method. The result indicates that the method calculates quickly, and when the tool nears a boundary, the method can be used to identify the boundary and determine the distance from the logging tool to the boundary in time. Additionally, the formation parameters of the algorithm in the field can be determined after a simple method is proposed based on the information of an offset well. Therefore, the forward method can be used for geosteering in the field. A field example validates that the forward method can be used to determine the distance from the azimuthal gamma-ray logging tool to the boundary for geosteering in real-time.

[1]  Jason L. Pitcher,et al.  Deep Electrical Images, Geosignal, and Real-Time Inversion Help Guide Steering Decisions , 2009 .

[2]  Michael S. Bittar,et al.  Azimuthal Wave Resistivity Opens A Window On The Geology Away From The Wellbore Path , 2009 .

[3]  J. Pitcher,et al.  A New Azimuthal Gamma at Bit Imaging Tool for Geosteering Thin Reservoirs , 2009 .

[4]  D. Nathan Meehan.  Geological Steering of Horizontal Wells , 1994 .

[5]  Richard Palmer,et al.  A New Deep Azimuthal Resistivity LWD for Optimal Well Placement and Reservoir Exploitation; Successful Validation with Saudi Aramco , 2008 .

[6]  Martin D. Paulk,et al.  Real Real-time Geosteering , 2000 .

[7]  A. Rennie,et al.  THE INTRODUCTION OF AN AT-BIT NATURAL GAMMA RAY IMAGING TOOL REDUCES RISK ASSOCIATED WITH REAL-TIME GEOSTEERING DECISIONS IN COALBED METHANE HORIZONTAL WELLS , 2012 .

[8]  R. Lorentzen,et al.  Optimization of Well Trajectory Under Uncertainty for Proactive Geosteering , 2012 .

[9]  D. Dworak,et al.  Numerical modeling of the gamma-gamma density tool responses in horizontal wells with an axial asymmetry. , 2011, Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine.

[10]  M. Bittar,et al.  Real-Time Decisions With Improved Confidence Using Azimuthal Deep Resistivity and At-Bit Gamma Imaging While Drilling , 2009 .

[11]  M. S. Efnik,et al.  Using New Advances in LWD technology for Geosteering and Geologic Modeling , 1999 .

[12]  Monte Carlo Simulating of Three Detector Density Logging , 2004 .

[13]  S. J. Martin,et al.  Real-Time Azimuthal Gamma and Resistivity LWD Data Used to Navigate Complex Unconventional Reservoir - Western US Land , 2013 .

[14]  Jason L. Pitcher,et al.  A New Azimuthal Deep-Reading Resistivity Tool for Geosteering and Advanced Formation Evaluation , 2009 .

[15]  Michael S. Bittar,et al.  The Link Between Resistivity Contrast And Successful Geosteering , 2011 .

[16]  J. Pitcher,et al.  Multi-Sensor Geosteering , 2010 .

[17]  R. A. Meador.  Logging-While-Drilling A Story Of Dreams, Accomplishments, And Bright Futures , 2009 .

[18]  M. Diab,et al.  Unconventional Horizontal Well Placement Challenges - LWD Geosteering Applications Utilizing a Unique Spectral Azimuthal Gamma Ray in Real Time , 2014 .

[19]  R. Mottahedeh,et al.  Horizontal Well Geosteering: Planning, Monitoring And Geosteering , 2008 .

[20]  Carlos Carrion,et al.  Successful Geosteering in Ecuador Using the "Bright Spot" Phenomenon From Deep Resistivity Images , 2009 .

[21]  Jason L. Pitcher,et al.  Real Time Proactive Optimal Well Placement using Geosignal and Deep Images , 2010 .

[22]  Geoff Weller,et al.  A New-Generation LWD Tool With Colocated Sensors Opens New Opportunities for Formation Evaluation , 2007 .

[23]  Shao Cai,et al.  A fast forward algorithm for LWD gamma-ray response and its geosteering application , 2013 .

[24]  Cancan Zhou,et al.  A novel method for quantitative geosteering using azimuthal gamma-ray logging. , 2015, Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine.