Warning Signs of High-Pressure Formations of Abnormal Contour Pressures When Drilling for Oil and Natural Gas

Abstract

When drilling to obtain hydrocarbons (oil and natural gas), we cannot underestimate the anomalously high pressures in the deposit layers, as these pressures can cause an uncontrollable eruption. Therefore, it is important to look for signs of anomalous high contour pressures over time, which, according to a detailed analysis, could be used to predict and quantify high formation pressures. These arise under conditions of intense vertical migration of formation fluids, where the liquids in the well have to carry part of the weight of overlying rocks and are often also related to tectonic activity. The main aim of the present study was to detect the emergence of a gas kick, which, as a result of an improper technological procedure, can cause an uncontrollable eruption, which can lead to a total accident of the well. In this article, we describe the use of modern drilling technology and sophisticated software that displays the current status inside the well. These can reveal impending pressure anomalies that can cause complications in managing the gas kick in oil and natural gas drilling. We analysed the most appropriate procedure for well control in a hydrocarbon well using the “driller’s method” and the “wait and weight method”. On the basis of theoretical background, we verified the correctness of the procedure for well control and compared it with the reaction to gas kick from a well drilled in Hungary. In the article, we highlight mistakes, as well as the particular importance of properly managing gas kick and its early prediction. Proper management of gas kick and its early prediction highlight the particular importance of implementing safe and effective procedures in well drilling.

Features of forecasting abnormally high reservoir pressures when drilling wells in areas of south-western Turkmenistan

“…In particular, in geodynamic systems there are deformation-tensioned zones where anomalously high formation pressures are formed under the influence of highfrequency and deformation wave fields. Analyses of field deposits show that the relationship between anomalously high formation pressures and filtration-capacitance properties of rocks can be the cause of the formation of these pressures (2) . For example, low values of porosity and permeability of sandy silty rocks indicate the important role of fracture-pore reservoirs and secondary pore-type reservoirs in the formation of formation pressure anomalies (8) .…”

“…From the point of view of genesis, there are two main conditions for the formation of AHFP and ALFP: the presence of impermeable cover at the reservoir, preventing the transmission of hydrostatic water pressure, and the inflow of gas phase from deep faults of underlying strata. It is also noted that the deterioration of filtration-capacitance properties of reservoir rocks can contribute to the formation of anomalous pressures, as the outflow of geofluids from the reservoirs is impeded (2) . The main reasons for the formation of anomalous reservoir pressures are: reservoir rock properties, pressure changes in the reservoir, tectonic movements, sedimentation rate, piezometric fluid level and sedimentation conditions.…”

“…Anomalously high formation pressures in clay rocks can cause the rocks to protrude inside the wellbore and collapse. In the case of thin lenticular reservoirs, this can be manifested by sudden ejections of clay mud during drilling (2) . When designing well construction, the prediction of formation pressures is carried out by analysing and generalizing the available material on the actually measured values of formation pressures in neighbouring wells or in neighbouring areas.…”

“…The multi-cyclic nature of oil and gas generation in the geological history determined the multistory of the oil and gas bearing complex of Meso-Cenozoic sediments. In the work carried out by T. Huszar et al (2) , studies were carried out to identify signs of temporary anomalously high contour pressures. Through detailed analyses, these features were identified and used to predict and quantify elevated reservoir pressures.…”

Dependency of Pressure Expression towards Formation Pressures during Drilling Operations in Hydrocarbon Wells and Suitable Choice of Pressure Control Method

“…-Use the drilling method to reduce the pressure on the bottom hole pressure and circulate the gas out. Assuming that the pressure will be constant, continue with the drilling method [22].…”