An Accurate Volumetric Calculation Method for Estimating Original Hydrocarbons in Place for Oil and Gas Shales including adsorbed Gas using High-Resolution Geological Model

Abstract

The emergence of liquid-rich and gas shale reservoirs presents major strategic opportunities and challenges for the oil and gas industry. Accurate estimation of Stock Tank Oil and Gas Initially In Place (STOIIP & GIIP) is one of the priority tasks before defining the reserves. An accurate method is proposed to calculate hydrocarbon volumes using high-resolution geological models taking advantage of huge improvements made during last decade in the field of characterization and geological modeling of unconventional reservoirs. This exact method provides fluids in place in reservoir and surface conditions with an extended black-oil formulation including condensates. The physic including the equilibrium between gravity and eventually capillary forces and adsorbed gas is fully respected using, for each lithofacies, the most accurate available geological description with 3D porosity distributions, Langmuir isotherms (Langmuir, 1918), capillary pressure curves, and thermodynamic data. Adsorbed and liquid-rich gases are considered. This method calculating hydrocarbons in place is the natural endpoint of any workflow devoted to the geological modeling of newly discovered reservoirs, particularly suited to heterogeneous reservoirs. The knowledge generated by this calculation has significant impact on fracturation programs to increase the recovery rate and field development planning.

Resource assessment of Silurian and Ordovician shales in the Baltic basin based on the results of 3D geological modelling – methodological aspects

“…This type of solution was presented, e.g. by [2] and developed in the form of a computational module, compatible with the Petrel software. One of the specific functions of this suite is the ability to determine the varying proportion of saturation of the shale rock with water, oil, condensate and gas in the transitional zones.…”

“…Due to this, these approaches are characterised by high diversity with respect to the types of the used geological, geochemical, petrophysical and engineering data. In general, the methods of the estimation of the geological resources of hydrocarbons in shale formations can be divided into several groups [2,3,6,8,9]:…”

Analiza porównawcza formacji łupkowych w wybranych strefach basenu bałtyckiego na podstawie interpretacji danych otworowych i wyników modelowania geologicznego 3D

“…Określanie perspektywiczności formacji łupkowych w formie ilościowej (np. dla obszaru zdjęcia sejsmicznego lub koncesji), jak również wskazanie optymalnych stref analizowanego obszaru wymagają opracowania map lub modeli przestrzennych dystrybucji parametrów wyznaczających ich potencjał zasobowy [2]. W ramach prowadzonych prac z zakresu modelowania geologicznego konstruowano modele strukturalne oraz rozkłady 3D następujących właściwości petrofizycznych i geochemicznych skał: gęstości objętościowej, porowatości całkowitej i porowatości efektywnej, zawartości substancji organicznej (TOC), nasycenia przestrzeni porowej skał łupkowych wodą złożową (Sw).…”

Geomechanical modellingl of Paleozoic Shale Gas Formation: a case study from the Baltic Basin, northern Poland

“…Reservoir characterization studies carried out for unconventional shale reservoirs include analysis, modelling and interpretation of much wider range of geological formations' properties. Apart from those considered for conventional reservoirs such as porosity, permeability, shale content, and hydrocarbons saturation, shale reservoirs also require profound reconnaissance of mineralogical composition, organic matter (TOC) as well as geomechanical properties (Romero & Philp 2012, Bruyelle & Guérillot 2014, Heege et al 2015. The latter determine parameters essential for stimulation treatment of unconventional shale formation.…”