Publications

Callus formation in Lavandula × intermedia varies widely depending on explant type, plant growth regulator composition, and cultivation duration, yet their combined effects remain insufficiently characterized. Here, 57 growth regulator treatments were evaluated using root- and stem-derived explants over a 15-week culture period. Callus induction occurred on most media and was typically initiated within the first three weeks, while biomass accumulation followed a biphasic pattern with a pronounced increase after week six, reaching up to 35 g depending on treatment. A combination of 0.5 mg L⁻¹ 2,4-D and 0.5 mg L⁻¹ kinetin consistently produced the highest biomass. To model system behavior, five statistical and machine learning approaches were applied. XGBoost achieved the highest predictive accuracy on experimental data (R² ≈ 0.94), whereas Random Forest showed the most stable performance across independent validation datasets. Feature importance analysis identified culture duration as the dominant factor influencing biomass, while hormonal composition significantly affected both responses and explant type had only a minor contribution. Multi-objective optimization using NSGA-II revealed multiple high-performing solutions, while induction converged to a single near-optimal condition. These findings demonstrate that integrating experimental data with machine learning enables robust prediction and optimization of callus responses in Lavandula × intermedia.

Abstract Arps’ hyperbolic model has historically been used to analyze and forecast gas well performance. This is largely due to its simplicity and explicit nature. Unfortunately, because of the variations of viscosity-compressibility product with average reservoir pressure during boundary-dominated flow (BDF) period, the Arps’ hyperbolic model overestimates gas reserves and future rates. Consequently, existing rate-decline models rely heavily on pseudotime. Unfortunately, pseudotime requires iteration, which is time-consuming. This paper proposes an empirical rate-decline model for a gas well producing at a constant pressure during BDF. The proposed model utilizes a drawdown correlating parameter that accounts for formation and water compressibilities, as well as the variations of gas properties with pressure. Due to its explicit nature, the proposed rate-decline model can be used to forecast future gas well performance. An explicit model for estimating the decline exponent for a gas well is also proposed. In addition, this paper presents a semi-empirical flowing material balance (SE-FMB) method that allows the estimation of initial gas-in-place, real gas productivity index and estimated ultimate recovery. The advantages of the proposed SE-FMB over the existing methods are two-folds: first, it is iterationless; and second, it avoids the use of a functional relation (or curve fitting) of viscosity-compressibility product and pressure. The results of this study suggest that the decline exponent for a gas well is time-independent at early-time BDF period and time-dependent at late-time BDF period. At very late-time BDF period, the decline exponent tends to zero. Thus, gas well production data exhibit a hyperbolic decline at early-time BDF period and a transition period at late-time BDF period. At very late-time BDF period, an exponential decline is expected. While the exponential-decline period is not observed in practice due to economic-rate constraints, the hyperbolic-decline period is observed in practice. The transition period may or may not be observed in practice depending on the magnitude of the drawdown parameter and the economic-rate constraints. Comparison of the models results indicates that the proposed rate-decline and the classical Arps’ hyperbolic models are consistent with the rate history during the hyperbolic-decline period; however, the proposed rate-decline model out-performs the classical Arps’ hyperbolic model when the transition period prevails. The results of this study also indicate that ignoring the formation and water compressibilities lead to an overestimation of gas reserves even for a normally-pressured gas reservoir. Simulated and field data have been used to demonstrate the validity and applicability of the proposed model and analysis method.

Abstract We investigate, through a graphical representation of dimensionless pseudocumulative function, the possibility of using only the early time boundary-dominated flow (BDF) data to make an initial estimate of gas-in-place. In particular, we demonstrate that when viscosity-compressibility product ratio is plotted against fractional recovery on linear coordinates, an early straight line is observed during BDF regime. This phenomenon permits the dimensionless pseudocumulative function to be expressed as a quadratic function which, upon approximation, yields a linear function in terms of fractional recovery. This work thus demonstrates that the utilization of actual cumulative in gas flowing material balance yields two negative slopes − early time and late time BDF lines. As opposed to the late time BDF line, the early time BDF line yields a reasonable initial gas-in-place, and thus considerably reduces the number of time-consuming iterations associated with computing material balance pseudotime function. Perhaps, the significant finding of this work is that it establishes that the approximate gas flowing material balance equation is strictly applicable to the early time BDF data. Simulated and field data for both single- and multi-well systems are presented to demonstrate the applicability of the proposed approach.