Production Data Analysis of Liquid Rich Shale Gas Condensate Reservoirs

Abstract

With the current focus on liquids-rich shale plays (LRS) in North America and the importance of gas condensate reservoirs globally, there is an increased need to develop reservoir engineering methods to analyze such reservoirs. Commercialization of LRS plays is now possible due to new technology, such as multi-fractured horizontal wells (MFHW). Efficient production from such reservoirs necessitates understanding of flow mechanisms, reservoir properties and the controlling rock and fluid parameters. Production-decline analysis is a robust technique for analysis of production data and obtaining estimates of recoverable reserves. Nevertheless, these techniques, developed for conventional reservoirs, are not appropriate for ultra-low permeability reservoirs. There are substantial differences in reservoir performance characteristics between conventional and ultra-low permeability reservoirs. LRS reservoirs produce much leaner wellstreams compared to conventional reservoirs due to very low permeabilities that result in very large drawdowns. Methods for analysis of two-phase flow in conventional reservoirs, with underlying simplifying assumptions, are no longer applicable. This paper discusses production data analysis of constant flowing bottomhole pressure (FBHP) wells producing from LRS (gas condensate) reservoirs. A theoretical basis is developed for a gas condensate reservoir during the transient linear flow (drawdown) period. The governing flow equation is linearized using appropriately defined two-phase pseudopressure and pseudotime functions so that solutions valid for liquids can be applied. The derived backward model is employed to compute the linear flow parameter, xf√k. Simulation results show that the liquid yield will be approximately constant for LRS wells during the transient linear flow, from the early days of initial testing, if flowing BHP is almost constant. An analytical formulation is used to prove this finding for 1D transient linear flow of LRS wells. The proposed production data analysis (PDA) method is illustrated using simulated production data for different fluid models and relative permeability curves. Fine-grid compositional and black oil numerical models are used to this purpose.

Treatment of Condensate and Water Blocks in Hydraulic-Fractured Shale-Gas/Condensate Reservoirs

“…The compositional simulation of a gas/condensate well was performed by use of UTCOMP (Chang 1990) with a three-phase flash option. A horizontal producer with a lateral length of 5,000 ft was modeled; 25 transverse fractures were distributed along the wellbore with equal spacing of 200 ft.…”

“…This discontinuity often reduces the timestep size and causes the simulation to slow down or stop as well as being physically incorrect. In this study, the three-phase flash simulator UTCOMP (Chang 1990) was used to simulate the solvent-stimulation process. The relative permeability option developed by was used in UTCOMP for this study.…”

Parameter Optimization of Segmental Multicluster Fractured Horizontal Wells in Extremely Rich Gas Condensate Shale Reservoirs

“…The exploration of this kind of liquid-rich shale condensate gas reservoir is still in initial stage. In recent years, scholars have carried out researches on different aspects (Behmanesh et al, 2013;Labed et al, 2015;Xu, 2016;Di et al, 2019;Guo et al, 2019;Qian et al, 2021;Zhi et al, 2021). Taylor et al (2014) constructed an allcomponent dual-permeability model to simulate the flow after fracturing in the well group and studied the contribution of primary and secondary fracture systems to the production of liquid-rich shale gas reservoirs while ignoring the optimization of artificial fracture systems.…”

Environmental Impact of Exploration from Unconventional Gas Deposits in Poland

“…At present shales, which have a considerable concentration of organic matter (total organic carbon (TOC) above 1.5-2%), high thermal maturity index (vitrinite reflectance coefficient (Ro) above 1.3%) and which occur in complexes of thickness exceeding 30 m are used as unconventional deposits for advanced production of natural gas [5][6][7]. Unconventional gas deposits may also cover gas-condensate or purely gaseous deposits [8,9]. Determining two-phase zones is vital for gas-condensate deposits [3,10].…”