Analysis of Reservoir Performance of the Messoyakha Gas Hydrate Reservoir

Abstract

The Messoyakha Gas Field is located in Siberian permafrost. The field has been described as a free gas zone, overlaid by hydrate layer and underlain by an aquifer of unknown strength. The field was put on production in 1970 and has produced intermittently since then. Some characteristic observations were increase in average reservoir pressure during shut-in, perforation blocking due hydrate formation and no change in gas-water contact. It is believed the increase in reservoir pressure was caused by the hydrate layer dissociation, rather than aquifer influx. The objective of this study is to use numerical model to analyze the observed production data from the Messoyakha field. In this study, a range of single-well 2D cross-sectional models representative of Messoyakha have been developed using Tough + Hydrate reservoir simulator. The simulation results were analyzed and compared with various field observations. Further, we have done a parametric study of reservoir properties of hydrate capped gas reservoir. We have used Tough + Hydrate to simulate the observed gas production and reservoir pressure data at Messoyakha. We simulated various scenarios that help to explain the field behavior. We have evaluated the effect of various reservoir parameters on gas recovery from hydrates. Our work should be beneficial to others who are investigating how to produce gas from hydrate capped gas reservoir. We were able to generate results that are very similar to the reported flow rates and pressure behavior in Messoyakha Field. The value of absolute permeability in the hydrate layer and the lower free gas layer substantially affects the continued dissociation of hydrates during shut-down. We also modeled the formation of secondary hydrates near the wellbore that can cause the reduced gas flow rates. The important parameters affecting the gas production are the formation permeability in the gas layer, the effective gas vertical permeability in hydrate layer, the location of perforations, and gas hydrate saturation. We have described various scenarios which are beneficial as well as detrimental in producing gas from hydrate capped gas reservoirs. We have also listed various parameters that should be carefully measured for accurate modeling work. Introduction Natural gas hydrates have been the subject of active research in the oil and gas industry since their role in blocking fluid flow in oil and gas pipelines was demonstrated by Hammerschmidt (1934). Later, Makogon (1965) proposed that naturally occurring gas hydrates could exist in the earth's subsurface. Since 1965, a number of research projects have been performed to estimate and quantify the volume of naturally occurring gas hydrates. Although there is uncertainty over the quantity and distribution of naturally occurring hydrates in the earth, there is general agreement that substantial volumes of gas hydrates do exist in nature (Sloan and Koh, 2008). According to the latest data gathered by various expeditions for hydrates, the gas resource in hydrate ranges from 105 to 106 Tcf (US Department of Energy, 2007). Natural gas hydrates (NGH) are crystalline compounds formed by the association of molecules of water with natural gas. NGHs are a subset of substances known as clathrates, which means "cage like structures". The formation of natural gas hydrates depends upon pressure, temperature, gas composition, and the presence of inhibitors such as salts. NGHs are found in the subsurface in two distinct types of settings. One is the permafrost in arctic regions and the second is in deepwater marine environments.

Towards Commercial Gas Production from Hydrate Deposits

“…It was estimated that about 36% (5.17 × 10 9 m 3 ) of the gas produced was from the hydrate zone [29,38]. While a review of available geological, geochemical and production data by Collett and Ginsburg [29,39] indicated that the overlying gas hydrates may not have been contributing significantly to gas production, in a more recent numerical simulation study of the Messoyakha field, results similar to the actual reported flow rates and pressure behaviour were observed [40]. The results of the numerical simulation study indicated that as much as 15-20% of the gas produced from the Messoyakha field came from dissociation.…”

Numerical simulation of Class 3 hydrate reservoirs exploiting using horizontal well by depressurization and thermal co-stimulation

“…The value of dimension width, 400 m, was set after referenced Grover' physical model whose value was 350 m in diameter [7]. The horizonal length was set as 1495.2 m to ensure that the reservoirs contain large amount of hydrates, and if correct strategy were taken, large amount of natural gas would be produced.…”

“…Many countries paid great attention to hydrates with the traditional fossil energy exhaustion and its wide range of applications developed in many field [3]. America had made all-round studies on hydrate dissociation in industry level [4][5][6][7]. Japan had made long-term strategies on the gas hydrates exploitation from Nankai Trough, and they hoped the hydrate reservoirs in Nankai Trough could be dissociated in the near future [8,9].…”

Multiphase non equilibrium pipe flow behaviors in the solid fluidization exploitation of marine natural gas hydrate reservoir

“…Through the methods of depressurization, heat shock, chemical injection, and replacement, methane gas is released by hydrates decomposition or replacement, and then is produced. Existing examples of exploiting natural gas hydrate reservoir are mainly included as follows: In the Messoyakha gas field of Siberia area, the gas is produced from hydrate decomposition by means of depressurization and chemical injection . In the Mallik area of Canada, two hydrate samples were tested by means of depressurization and heat injection .…”