Integrating Pressure Transient and Rate Transient Analysis for EUR Estimation in Tight Gas Volcanic Reservoirs

2017 ◽  
Author(s):  
A. Beohar ◽  
S. K. Verma ◽  
V. Sabharwal ◽  
R. Kumar ◽  
P. Shankar ◽  
...  
Keyword(s):  
Transient Analysis ◽  
Tight Gas ◽  
Pressure Transient ◽  
Rate Transient Analysis ◽  
Volcanic Reservoirs

The Use of Rate-Transient-Analysis Modeling To Quantify Uncertainties in Commingled Tight Gas Production-Forecasting and Decline-Analysis Parameters in the Alberta Deep Basin

2014 ◽  
Vol 17 (02) ◽  
pp. 209-219 ◽  
Author(s):  
H.. Luo ◽  
G.F.. F. Mahiya ◽  
S.. Pannett ◽  
P.. Benham
Keyword(s):  
Transient Analysis ◽  
Early Time ◽  
Gas Production ◽  
Tight Gas ◽  
Well Performance ◽  
Deep Basin ◽  
Type Curves ◽  
Production Forecasting ◽  
Rate Transient Analysis ◽  
Production History

Summary The evaluation of expected ultimate recovery (EUR) for tight gas wells has generally relied upon the Arps equation for decline-curve analysis (DCA) as a popular approach. However, it is typical in tight gas reservoirs to have limited production history that has yet to reach boundary-dominated flow because of the low permeability of such systems. Commingled production makes the situation even more complicated with multiboundary behavior. When suitable analogs are not available, rate-transient analysis (RTA) can play an important role to justify DCA assumptions for production forecasting. The Deep-basin East field has been developed with hydraulically fractured vertical wells through commingled production from multiple formations since 2002. To evaluate potential of this field, DCA type curves for various areas were established according to well performance and geological trending. Multiple-segment DCA methodology demonstrated reasonable forecasts, in which one Arps equation is used to describe the rapidly decreasing transient period in early time and another equation is used for boundary-dominated flow. However, a limitation of this approach is the uncertainty of the forecast in the absence of extended production data because the EUR can be sensitive to adjustments in some assumed DCA parameters of the second segment. In this paper, we used RTA to assess reservoir and fracture properties in multiple layers and built RTA-type well models around which uncertainty analyses were performed. The distributions of the model properties were then used in Monte Carlo analysis to forecast production and define uncertainty ranges for EUR and DCA parameters. The resulting forecasts and EUR distribution from RTA modeling generally support the DCA assumptions used for the type curves for corresponding areas of the field. The study also showed how the contribution from the various commingled layers changes with time. The proposed workflow provides a fit-for-purpose way to quantify uncertainties in tight gas production forecasting, especially for cases when production history is limited and field-level numerical simulation is not practicable.

Investigation of permeability change in the Bandanna Coal Formation of the Fairview Field using time-lapse pressure transient analysis

2019 ◽  
Vol 59 (1) ◽  
pp. 289 ◽  
Author(s):  
A. Salmachi ◽  
J. Barkla
Keyword(s):  
High Resolution ◽  
Transient Analysis ◽  
Time Lapse ◽  
Production Performance ◽  
Reservoir Pressure ◽  
Permeability Change ◽  
Pressure Transient Analysis ◽  
Pressure Transient ◽  
Coal Permeability ◽  
Rate Transient Analysis

Permeability of coal seam gas (CSG) reservoirs is stress/desorption dependent and may change during the life of the reservoir. This study investigates permeability change with depletion in several CSG wells in the Fairview Field: a prolific reservoir in the Bowen Basin, Australia. High-resolution pressure gauges at surface provide an opportunity to conduct time-lapse pressure transient analysis (PTA) on the wells that have multiple shut-ins. Pressure build-up tests can be replicated by calculating bottom-hole pressure when surface pressure (tubing and/or annulus) is recorded at high-resolution during any shut-in event. This eliminates the need to perform multiple well tests, which are time consuming and costly to run. The production history of 100 CSG wells was examined to find suitable candidates to perform time-lapse PTA. This was used to investigate how Bandanna Coal permeability changes with depletion. Three wells with high-quality shut-ins were identified and analysed to calculate effective permeability to gas and average reservoir pressure. The results indicate that coal permeability can enhance up to one order of magnitude during the life of a CSG well in the Fairview Field, and this can significantly improve production performance. These wells, located in a depleted area of the field, show rapid increase in permeability with decline in average reservoir pressure. The integration of rate transient analysis with the results of time-lapse PTA for one of the study wells reveals that the functional form of permeability increase is exponential in the study area, and a permeability modulus of –0.00678 psia–1 was obtained.

A Semianalytical Methodology To Diagnose the Locations of Underperforming Hydraulic Fractures Through Pressure-Transient Analysis in Tight Gas Reservoir

SPE Journal ◽  
2016 ◽  
Vol 22 (03) ◽  
pp. 924-939 ◽  
Author(s):  
Youwei He ◽  
Shiqing Cheng ◽  
Shuang Li ◽  
Yao Huang ◽  
Jiazheng Qin ◽  
...  
Keyword(s):  
Production Rate ◽  
Transient Analysis ◽  
Gas Production ◽  
Hydraulic Fractures ◽  
Tight Gas ◽  
Well Performance ◽  
Gas Reservoir ◽  
Pressure Transient ◽  
Type Curves ◽  
Tight Gas Reservoir

Summary The increasing activities in tight reservoir exploitation through fractured wells have attracted interests of pressure-transient analysis (PTA) for well-performance evaluation. The production rates of different fractures were assumed to be equal in previous models. However, different fractures have unequal contributions to the total-gas-production rate because of the differences of fracture scale (e.g., half-length, height), heterogeneity of gas saturation, formation damage, and fracture closure. This paper considers the effect of unequal gas-production rate of each fracture (UGPREF) on pressure-transient behaviors, and develops a semianalytical methodology to diagnose the specific locations of underperforming fractures through PTA by use of bottomhole-pressure (BHP) data. First, new semianalytical solutions of a multifractured horizontal well (MFHW) in a tight gas reservoir are derived on the basis of the Green function (Gringarten and Ramey 1973) and Newman product method (Newman 1936). Second, the model is validated by comparison with the numerical model in KAPPA Ecrin (Saphir) software (Essca 2011). Third, type curves are developed, and sensitivity analysis is further investigated. Results show that there exist clear distinctions among these type curves between equal gas-production rate of each fracture (EGPREF) and UGPREF. The early radial flow is distinguishable and behaves as a horizontal line with the value of 0.5/N* (N* = N for EGPREF, N*≠N for UGPREF) in the pseudopressure-derivative curves when the interferences between fractures do not overlap this period. If the early-radial flow was mistakenly regarded as pseudoradial flow, the interpreted permeability would be N* times smaller than the accurate result. Furthermore, the methodology is applied to a field case of the Daniudi tight gas reservoir in the Ordos Basin, which illustrates its physical consistency and practicability to diagnose the specific locations of underperforming hydraulic fractures through pressure-history matching. It also provides feasible references for reservoir engineers in well-performance evaluation and field strategy (e.g., refracturing, acidizing, or other stimulation treatments) to enhance hydrocarbon production.

Fracture Geometry Calibration Using Multiple Surveillance Techniques

2022 ◽  
Author(s):  
Musallam Jaboob ◽  
Ahmed Al Shueili ◽  
Hussien Al Salmi ◽  
Salim Al Hajri ◽  
German Merletti ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Transient Analysis ◽  
Earth Model ◽  
Tight Gas ◽  
Radioactive Tracers ◽  
Multiple Sources ◽  
Pressure Transient Analysis ◽  
Fracture Geometry ◽  
Pressure Transient ◽  
Tight Gas Reservoir

Abstract An accurate Mechanical Earth Model (MEM) is of vital importance in tight gas reservoirs where hydraulic fracturing is the only way to produce hydrocarbons economically. The Barik tight gas reservoir is the main target in Khazzan and Ghazeer Fields at the Sultanate of Oman (Rylance et al., 2011). This reservoir consists of multiple low-permeability sandstone layers interbedded with marine shales. A good understanding of the fracture propagation in such a reservoir has a major effect on completion and fracturing design. The MEM derived from sonic logs and calibrated with core data needs to be further validated by independent measurements of the fracturing geometry. Multiple surveillance techniques have been implemented in the Barik reservoir to validate the MEM and to match observations from hydraulic fracturing operations. These techniques include closure interpretation using a wireline deployed formation testing assembly, the use of mini-frac injection tests with deployed bottomhole pressure gauges, execution of post injection time-lapse temperature logging, the injection of radioactive tracers, associated production logging, subsequent pressure transient analysis and other techniques. A cross-disciplinary team worked with multiple sources of data to calibrate the MEM with the purpose of delivering a high-confidence prediction of the created fracture geometry, which honors all available surveillance data. In turn, this validation approach provided a solid basis for optimization of the completion and fracturing design, in order to optimally exploit this challenging reservoir and maximize the economic returns being delivered. For example, combination of stress testing with radioactive tracers provided confidence in stress barriers in this multilayered reservoir. Pressure transient analysis allowed to calibrate mechanical model to match fracturing half-length that is contributing to production. This paper provides extensive surveillance examples and workflows for data analysis. Surveillance of this degree in the same well is uncommon because of the associated time and cost. However, it provides unique value for understanding the target reservoir. This paper demonstrates the Value Of Information (VOI) that can be associated with such surveillance and provides a concrete and practical example that can be used for the justification of future surveillance programs associated with the hydraulic fracturing operations.

Sign in / Sign up

Export Citation Format

Share Document