Laboratory, numerical and field assessment of the effectiveness of cyclic geomechanical treatment on a tournaisian carbonate reservoir

Abstract

Results are discussed for evaluation of effectiveness of the cyclic geomechanical treatment (CGT) on a Tournaisian carbonate reservoir. Analysis of laboratory experiments performed according to a special program to assess permeability changes for Tournaisian samples under cyclic changes in pore pressure is presented. The main conclusion is the positive selectivity of the CGT: an increase in permeability is observed for samples saturated with hydrocarbons (kerosene) with connate water, and maximal effect is related to the tightest samples. For water-saturated samples, the permeability decreases after the CGT. Thus, the CGT improves the drainage conditions for tight oil-saturated intervals. It is also confirmed that the CGT reduces the fracturing pressure in carbonate reservoirs. Using flow simulations on detailed sector models taking into account the results of laboratory experiments, a possible increase in well productivity index after CGT with different amplitudes of pressure variation was estimated. Results of a pilot CGT study on a well operating a Tournaisian carbonate reservoir are presented, including the interpretation of production logging and well testing. The increase in the well productivity index is estimated at 44-49 % for liquid and at 21-26 % for oil, with a more uniform inflow profile after the treatment. The results of the field experiment confirm the conclusions about the mechanisms and features of the CGT obtained from laboratory studies and flow simulations.

Paleoenvironmental Evaluation Using an Integrated Microfacies Evidence and Triangle Model Diagram: A Case Study from Khurmala Formation, Northeastern Iraq

“…These bio-components are linked to FZ 7, which reflects a shallow marine environment with moderate water circulation (FZ 8), while there is a shifting in this diagram, mostly toward an open-platform environment ( FZ 7). Another open platform indicator is described in Flügel [14], in which modern calcareous green algae and the occurrence of Clypeina in grainstones is considered a satisfactory indicator for an open platform [24][25][26][27][28][29][30]. Therefore, the integrated methods for analyzing the paleoenvironment of the Khurmala Formation reveal a semi-restricted back-reef environment, which represent the main characteristic of the depositional environment of the Khurmala Formation.…”

“…These bio-components are linked to FZ 7, which reflects a shallow marine environment with moderate water circulation (FZ 8), while there is a shifting in this diagram, mostly toward an open-platform environment ( FZ 7). Another open platform indicator is described in Flügel [14], in which modern calcareous green algae and the occurrence of Clypeina in grainstones is considered a satisfactory indicator for an open platform [24][25][26][27][28][29][30].…”

Improvement in simulation methods, laboratory studies and field surveys for creating new technologies of efficient environmentally friendly hydrocarbon production at complex geological conditions

“…Вып. 3 (42) Резюмируя, можно утверждать, что в рамках выполняемой темы госзадания на основе комплексного научно-методического подхода обоснованы технологические решения по совершенствованию систем разработки залежей углеводородов при наличии подошвенной воды в различных геолого-физических условиях, включая применение альтернативы технологии гидроразрыва пласта в виде циклического геомеханического воздействия для нефтяных залежей в низкопроницаемых карбонатных коллекторах Республики Татарстан [10]; специализированную систему разработки для водоплавающих газовых залежей [12,13]; технологию вертикальнолатерального заводнения для нефтяной оторочки, подстилаемой водой (на примере месторождения Монги о. Сахалин) [46,47].…”