In conventional wireline and LWD/MWD formation testing, downhole predictions for rock and fluid properties are based on simplified Darcy flow models, but only for mathematical expediency. These require initially constant pressures that are uniform throughout the reservoir. This limitation precludes common applications in overbalanced drilling, so that supercharge or near-well invasion effects - associated with rapidly decreasing pressures at the sandface where pressures are measured - are completely ignored. Such 1990s math models are commonly used despite documented field results for overbalances as high as 2,000 psi. Incorrect modeling can produce incorrect predictions, leading to misleading formation evaluation results and economic analyses. Here, the conventionally accepted model (developed by the last author over two decades ago) is rigorously extended to allow general supercharge and also underbalanced drilling effects. The formulation and algorithm are explained and detailed pressure examples are offered showing essential differences between earlier and newer algorithms.

Wireline Formation Testing is an important technique in the oil field of exploration and development. Not only it can make real fluid samples of the formation directly obtained to know exactly oil existed in formation or not; but it can also show flowing pressure change to see the production capacity of the formation. So it is important measurement for formation evaluation during the drilling process and supports for activities of the exploration and development in the oil field. A numerical simulation model in this article is researched and established based on the Finite Volume Method with considering the influence of sensitive parameters such as reservoir heterogeneity, probe suction area, and mud-filtrate invasion depth during the drilling. The model is capable to design and evaluate for formation fluid sampling operations with calculating hydrocarbon content and flowing pressure. Furthermore, through case application, the performance and effect in the process of Wireline Formation Testing was demonstrated. The results indicate that this technology can be served as an effective auxiliary tool for fluid sampling operations with the function of optimizing fluid sampling measures. It can improve the accuracy of predicting indicators such as hydrocarbon content and breakthrough time during the sampling process. This study provides important backups and technical guidance for professionals in geological exploration and oilfield development.

The aim of this study is to evaluate whether a random-forest model trained on conventional well logs can reconstruct missing shear-wave slowness (DTS) with sufficient transparency for downstream geomechanical calculations. Field-acquired DTS and 12 conventional curves from Well A were used for model development and progressive feature screening; an 11-variable subset was retained as a parsimonious input set, and Well Y was used as an external cross-block test. A re-audit of the prediction pairs embedded in the manuscript gave R² = 0.97, MAE = 3.404 μs/ft, and RMSE = 5.718 μs/ft for the plotted Well A profile (n = 1873), and R² = 0.91, MAE = 3.103 μs/ft, and RMSE = 3.658 μs/ft for Well Y (n = 255). Because the archived dataset lacks the raw feature-by-depth matrix, complete training settings, aligned density data, and core-based static-property measurements, depth-blocked retraining and numerical validation of mechanical properties could not be performed. The contribution is therefore an error-audited two-well DTS-completion case study and a transparent interface to potential geomechanical applications, not a validated hydraulic-fracturing design method.

Wireline formation testing is an important technique in the exploration and development of oil fields. Not only can real fluid samples be prepared from the formation directly obtained to know exactly whether the oil existed in the formation or not, but it can also show flowing pressure change to determine the production capacity of the formation. So, it is an important measurement method for formation evaluation during the drilling process and supports activities related to the exploration and development of oil fields. A numerical simulation model in this article is researched and established based on the finite volume method considering the influence of sensitive parameters such as reservoir heterogeneity, probe suction area, and mud-filtrate invasion depth during the drilling. The model is capable of designing and evaluating formation fluid sampling operations by calculating hydrocarbon content and flowing pressure. Furthermore, through case application, the performance and effect of the process of wireline formation testing were investigated. The results indicate that this technology can serve as an effective auxiliary tool for fluid sampling operations with the function of optimizing fluid sampling measures. It can improve the accuracy of predicting indicators such as hydrocarbon content and breakthrough time during the sampling process. This study provides important supporting evidence and technical guidance for professionals in geological exploration and oil field development.