Performance Index Method for Quantifying Stimulated Rock Quality
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Solution Overview
Problem
Conventional methods for developing oil and gas fields, such as well spacing and wellbore stimulation, are inefficient in accurately defining differences in rock quality within reservoirs, leading to suboptimal well placement and stimulation design, and fail to normalize performance data across different choke sizes.
Innovation Solution
A performance index method is introduced to quantify stimulated rock quality by calculating a performance index (PI) using average daily production rate, drawdown, and cumulative production data, allowing for the grouping of wells by PI values to define performance areas and optimize well placement and stimulation design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional well spacing and stimulation methods are used, then field development can proceed with standard practices, but accuracy in defining rock quality differences is poor leading to inefficient development
Solution Approach 1:
The patent applies parameter changes by introducing a performance index (PI) that combines multiple production parameters (cumulative production, average daily rate, average drawdown, and gross perforated interval) into a single quantitative metric. This transformation enables precise differentiation of rock qualities across the reservoir, directly resolving the contradiction by improving measurement precision without compromising development efficiency
Solution Approach 2:
The patent replaces conventional qualitative or semi-quantitative rock quality assessment methods with a data-driven performance index calculation system. By substituting traditional field development approaches with this quantitative framework, the patent achieves accurate rock quality definition while maintaining efficient field development progression
2Productivity
If conventional stimulation design methods are used, then stimulation can be performed with standard procedures, but the number of wells drilled may be insufficient or excessive and development planning is inefficient
Solution Approach 1:
The patent applies local quality by using the performance index to identify and categorize different rock quality zones within the reservoir. This enables tailored well placement and stimulation design for each zone, optimizing the number of wells drilled in each area rather than applying uniform spacing across the entire field, thereby improving development planning efficiency while accurately determining the optimal quantity of wells
Solution Approach 2:
The patent implements preliminary action by calculating performance indices and defining performance areas before actual well drilling and stimulation activities. This advance planning using PI-based rock quality classification allows optimized well placement and stimulation design to be established beforehand, preventing both insufficient and excessive well drilling while improving overall development efficiency
3Adaptability or versatility
If performance data is analyzed without normalization, then analysis can be performed on raw data, but wells operated on different choke sizes cannot be properly compared
Solution Approach 1:
The performance index serves as a universal metric that normalizes performance data across wells operated on different choke sizes. By incorporating multiple parameters (cumulative production, average daily rate, average drawdown, and gross perforated interval) into the PI calculation, the system creates a standardized comparison framework that adapts to various operating conditions while preserving meaningful performance information
Data Source
AI summary
A method determines the performance index of subterranean rock. In one embodiment, a performance index method determines a performance index for subterranean rock of an area. The area includes a well. The method includes determining a time period during producing the well. The method also includes determining the performance index from data of the time period from the equation PI=(q/dd)*(cum./GPI). The term PI is the performance index, and the term q is the average daily rate of the well for the time period. The term dd is the average drawdown per day of the well for the time period, and the term cum. is the cumulative production of the well for the time period. The term GPI is the gross perforated interval of the well for the time period.