Normalized Gas Parameter Drilling Model for Tight Reservoirs
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Solution Overview
Problem
In tight hydrocarbon reservoirs, accurately determining pore pressure is challenging due to unpredictable relationships between petrophysical log data and pore pressure, lack of direct pressure measurements, and unreliable gas parameters, leading to potential well instability and costly interventions.
Innovation Solution
A method involving the normalization of gas parameters using drilling parameters to create a drilling model that estimates pore pressure and correlates with hydrocarbons-in-place, allowing for real-time operation of well control devices to prevent kicks and maintain stable drilling conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional gas parameters are used to estimate pore pressure, then the estimation process is simple, but the accuracy is low and unreliable
Solution Approach 1:
The patent transforms the gas parameter estimation approach by introducing normalized gas parameters that account for drilling conditions. Instead of using raw gas parameters directly, the system normalizes them by dividing by drilling parameters (rate of penetration, bit diameter, pump rate) to create a corrected gas parameter that more accurately reflects formation pore pressure. This parameter transformation resolves the contradiction by improving accuracy while maintaining computational simplicity.
Solution Approach 2:
The patent introduces an intermediate normalized gas parameter as a mediator between the raw gas parameter and the final pore pressure estimation. This intermediate parameter serves as a bridge that accounts for drilling condition variations before the final pore pressure calculation, thereby improving accuracy without requiring direct complex measurements.
2Reliability
If support pressure is increased to prevent well collapse, then well stability is improved, but drilling speed decreases
Solution Approach 1:
The patent implements a feedback mechanism where the normalized gas parameter continuously monitors formation conditions and provides real-time information about pore pressure. This feedback allows dynamic adjustment of support pressure to match actual formation requirements, preventing both well collapse and unnecessary drilling slowdown. The system automatically adjusts drilling parameters based on the normalized gas parameter trends.
Solution Approach 2:
The patent transitions from static pore pressure estimation to a dynamic monitoring system using normalized gas parameters. The system continuously updates the gas parameter during drilling operations, allowing real-time adaptation of support pressure to changing formation conditions. This dynamic approach optimizes the balance between well stability and drilling speed.
3Reliability
If more pressure is applied than needed during drilling, then well stability is maintained, but drilling efficiency is reduced
Solution Approach 1:
The patent applies the principle of partial action by using only the necessary amount of support pressure required to maintain well stability, as indicated by the normalized gas parameter. Instead of applying excessive pressure uniformly, the system adjusts pressure to the minimum required level based on real-time formation conditions, thereby avoiding unnecessary drilling time loss while maintaining adequate formation stability.
Data Source
AI summary
Methods for modeling a tight hydrocarbon reservoir intersected by a borehole. Methods include using an estimated hydrocarbons-in-place value for the tight hydrocarbon reservoir and a gas parameter associated with drilling the borehole to create a drilling model. The model may determine an operation of a well control device associated with the borehole; or correlate the hydrocarbons-in-place value with the gas parameter for the tight hydrocarbon reservoir. Other methods include determining, during the forming of the borehole, an operation of a well control device associated with the borehole using an estimated hydrocarbons-in-place for the tight hydrocarbon reservoir and a gas parameter. The gas parameter may comprise a detected gas parameter normalized using at least one corresponding drilling parameter. Further methods include employing the model for performing operations in another borehole drilled in the same reservoir. Further methods include using the model to estimate a second hydrocarbons-in-place value in the other borehole.