Method for Forecasting the Efficiency of Matrix Acid Treatment of Carbonate

In the international practice of developing hydrocarbon fields, one of the most common methods of influencing the bottomhole formation zone to stimulate the inflow is acid treatment. Despite the significant accumulated experience, subsoil users increasingly face with a decrease in planned and actual increases in production rates after this type of measures, which is due to both the deterioration of the resource base and the adoption of erroneous decisions during their design. It is necessary to scientifically substantiate the design of acid treatments, taking into account individual well conditions and a preliminary assessment of their effectiveness to reduce technological and economic risks. This study presents a method for predicting the result of acid stimulation on the formation based on multivariate regression analysis and laboratory studies on rock samples. Its approbation was carried out on the example of a carbonate production facility of an oil field in the Perm Krai. The obtained statistical dependencies made it possible to determine with high accuracy the potential success of the planned geological and technical measures, to give recommendations on their adjustment to achieve the target indicators. In the course of laboratory experiments, the optimal technological parameters of the impact were identified: the prospects of multi-volume acid treatments were established with the exclusion of the stage of acid aging for the reaction. The integration of the results of mathematical and physical modeling made it possible to select the required design of acid treatments in relation to the considered geological and physical conditions and assess their expected technological efficiency. The developed technique can be used to rank candidate wells, form and adjust targeted programs for geological and technical measures for short and long term periods, and determine the stimulation technology. The described algorithm can be successfully replicated to other fields.

Seismicity and development of Romashkino hydrocarbon field’s Almetyevskaya area

The relationship between the various human activities and seismic activity has become more evident in the last several decades. One of the important domains where such a relationship manifests itself is hydrocarbon fields’ development. South East Tatarstan (Russia) is a region where the link between seismicity and the development of the giant Romashkino hydrocarbon field has been established. The goal of the current study is to conduct the causative analysis between the seismic activity and the development of the Romashkino hydrocarbon field’s Almetyevskaya area which is located in the most seismically active zone of the south-eastern Tatarstan.

Aquathermolysis of high-viscosity oil terrigenic sediments in the presence of iron oxide (II, III)

Nowadays, it is especially important and relevant to improve the efficiency of existing methods of enhanced oil recovery, in particular, thermal methods using water steam. The use of catalysis at the stage of development of unconventional hydrocarbon fields, namely super-viscous and bituminous oils, will allow solving this problem. This work is devoted to the study of the transformation of heavy oil from the Ashalchinskoye field in the process of catalytic aquathermolysis. The oil samples were extracts from sandstone, which was subjected to thermal steam treatment in a high-pressure reactor at temperatures of 200 and 250C for 24 h. Nanosized iron (II, III) oxide in complex with a hydrogen donor was used as a catalytic composition. According to the results of SARA-analysis, it was found that at a temperature of 200C, iron oxide does not show its catalytic properties, and there is no noticeable improvement in the composition of heavy oil. The destruction of resins and asphaltenes is observed after thermocatalytic treatment at 250C. This leads to the enrichment of oil with lighter hydrocarbons, which is confirmed by GC-MS data of the saturated fraction of oil. All this provides a significant decrease in the viscosity of heavy oil compared to the non-catalytic process from 1140 cP to 37 cP The formation of coke-like substances adsorbed on sandstone as a result of thermocatalytic action at 250C was revealed by the results of TG-DSC.

APPLICATIONS OF "SMART TECHNOLOGIES" IN OIL PRODUCTION AREAS

The article discusses the application of "smart technologies" in preventing the decline in production in the oil industry. Unlike other economic sectors, the factors that determine the application of "smart technologies" in the process of modeling and forecasting hydrocarbon fields by oil companies to increase production and ensure the safety of processes in the fields have been studied. The advantages of the application of "smart technologies" in ensuring the sustainable and dynamic development of oil companies are discussed here. Keywords: field, oil, machinery, technology, digital, factor, production.

Digital core modeling technology for determining the reservoir-capacitive properties of terrigenous reservoirs

For today digital core modelling technology is demanded and developing instrument in conducting the main reservoir-capacitive properties of terrigenous rocks. This technology is becoming more widespread in connection with the development of computer and nanotechnologies. The main attempts to apply the digital core model in practice have been undertaken in the last decade, although the first examples of its use for the analysis of reservoir rocks date back to the 80s of the last century. Improvement of digital core modeling technology will allow to cope with the problem of lack or absence of core material, as well as to solve the problems of studying loose, weakly cemented and other rocks, "problematic" of conducting physical experiments. In addition, it seems relevant to create a digital core block that fits into the general digitalization platform of technologies related to reservoir-capacitive properties in the development of hydrocarbon fields. With the use of a digital core model, it also becomes possible to effectively refine and supplement the calculated parameters in laboratory core studies, reducing the likelihood of errors in the obtained results.

Experimental evaluation of compressibility coefficients for fractures and intergranular pores of an oil and gas reservoir

The paper is devoted to studies of the volumetric response of rocks caused by changes in their stress state. Changes in the volume of fracture and intergranular components of the pore space based on measurements of the volume of pore fluid extruded from a rock sample with an increase in its all-round compression have been experimentally obtained and analyzed. Determination of the fracture and intergranular porosity components is based on the authors' earlier proposed method of their calculation using the values of longitudinal wave velocity and total porosity. The results of experimental and analytical studies of changes in porosity and its two components (intergranular and fractured) under the action of effective stresses are considered. This approach allowed the authors to estimate the magnitude of the range of changes in the volumetric compressibility of both intergranular pores and fractures in a representative collection of 37 samples of the Vendian-age sand reservoir of the Chayanda field. The method of separate estimation of the compressibility coefficients of fractures and intergranular pores is proposed, their values and dependence on the effective pressure are experimentally obtained. It is determined that the knowledge of the values of fracture and intergranular porosity volumetric compressibility will increase the reliability of estimates of changes in petrophysical parameters of oil and gas reservoirs caused by changes in the stress state during the development of hydrocarbon fields.

New Generation of Formation Testers – New Horizons: First Experience in Russia

As the production of oil and gas in major regions has been declining, exploration efforts are shifting towards hard-to-reach understudied areas with lack of necessary infrastructure. In addition to that, hydrocarbon fields that are being explored today, typically have more complex geological structure than the ones discovered decades ago and are characterized by the presence of multiple reservoirs with individual fluid contacts. The abovementioned reasons cause significant increase in time required to test these reservoirs and estimate their production potential. Therefore, there is a real need for reliable technologies that would expedite the testing of such complex fields. New wireline formation testing platform has an updated hardware architecture enabling to use it for both traditional formations testing applications as well as the development of new testing procedures deviating from conventional practices. This paper describes the novel testing approach implying the use of wireline formation tester (WFT) in conjunction with a surface multiphase flowmeter, which was implemented at one of the large gas fields located on the Gydan peninsula. A key feature of the new formation testing platform compared to its predecessors is its ability to pump an order of magnitude greater volumes of reservoir fluids, which allows to estimate permeability in the uninvaded zone of the reservoirs and their productivity. Combination of the wireline formation tester with the surface multiphase flowmeter enables measuring surface rates and capture surface samples of reservoir fluids thus making this type of testing comparable to traditional well testing. At the beginning of the paper we provide a brief description of the acquired formation testing results with stress on key features of the new wireline formation testing platform. The rest of the paper is devoted to Deep Transient Testing (DTT), more specifically, to its design and planning, required hardware and description of results acquired during such tests. We also demonstrate an approach that can be used to estimate reservoir productivity based on the obtained data.

Conditioning Model Ensembles to Various Observed Data (Field and Regional Level) by Applying Machine-Learning-Augmented Workflows to a Mature Field with 70 Years of Production History

Summary Forecasting production from hydrocarbon fields is challenging because of the large number of uncertain model parameters and the multitude of observed data that are measured. The large number of model parameters leads to uncertainty in the production forecast from hydrocarbon fields. Changing operating conditions [e.g., implementation of improved oil recovery or enhanced oil recovery (EOR)] results in model parameters becoming sensitive in the forecast that were not sensitive during the production history. Hence, simulation approaches need to be able to address uncertainty in model parameters as well as conditioning numerical models to a multitude of different observed data. Sampling from distributions of various geological and dynamic parameters allows for the generation of an ensemble of numerical models that could be falsified using principal-component analysis (PCA) for different observed data. If the numerical models are not falsified, machine-learning (ML) approaches can be used to generate a large set of parameter combinations that can be conditioned to the different observed data. The data conditioning is followed by a final step ensuring that parameter interactions are covered. The methodology was applied to a sandstone oil reservoir with more than 70 years of production history containing dozens of wells. The resulting ensemble of numerical models is conditioned to all observed data. Furthermore, the resulting posterior-model parameter distributions are only modified from the prior-model parameter distributions if the observed data are informative for the model parameters. Hence, changes in operating conditions can be forecast under uncertainty, which is essential if nonsensitive parameters in the history are sensitive in the forecast.