The current presentation date and time shown is a TENTATIVE schedule. The final/confirmed presentation schedule will be notified/available middle of October 2019. If we have learned anything from the North American experience, unconventional resources cannot be exploited by small incremental projects. If we are to be successful in developing these types of reservoirs, we have to make project scale operations work to bring these resources to market in a timely manner. A number of Eastern Hemisphere unconventional gas projects have raised interest, neared completion or are commencing deliveries.
Al-Bayati, Duraid (Curtin University) | Saeedi, Ali (Kirkuk University) | Ghasemi, Mohsen (Curtin University) | Arjomand, Eghan (Curtin University) | Myers, Mathew (Curtin University) | White, Cameron (CSIRO-Energy) | Xie, Quan (CSIRO-Energy)
Carbon dioxide (CO2) injection has been identified as an important means to achieve hydrocarbon reservoir potential whilst mitigating the greenhouse gas effect. CO2 injection into depleted oil reservoirs is very often accompanied by chemical interactions between the formation rock and in situ formed solute. Sandstone formations were expected to contain less reactive minerals in their composition, compared with carbonate counterparts. However, the evolution of petrophysical parameters may change due to different clay content in different sandstone rocks. In this manuscript, we evaluate possible petrophysical parameter evolution in layered sandstone core sample during miscible CO2 water alternating gas (WAG) injection. The stratified core sample is composed of two axially split half sandstone plugs each with different permeability. Grey Berea, Bandera Brown, and Kirby sandstone were used to represent low, moderate and high clay content, respectively. Core flooding experiments were conducted using CO2, brine (7 wt % NaCl + 5 wt % KCl + 5 wt % CaCl2.2H2O) and
The results showed a reasonable increase in the post-flood porosity about 1.0% as a maximum. The results also revealed that the changes in porosity are correlated reasonably with the clay minerals amount in the sample (i.e. higher clay mineral amount leads to higher evolution). The X-ray CT images and NMR results confirmed changes in pore spaces and pore size distribution across the core sample. These changes possibly attributed to clay minerals migration which released by mineral dissolution and subsequent pore throat plugging. NMR results also revealed that the larger the pore size, accompanied by high clay mineral amount, the higher the evolution. This may be attributed to the higher contact surfaces at these pores with the injected CO2 (in-situ formed carbonic brine).
Our results provide insight into how clay content may affect CO2/sandstone reaction in the presence of permeability/mineralogy heterogeneity. In addition, it highlights the control of clay content on rock petrophysical parameter evolution, thus its significance in modelling CO2 injection in sandstone reservoirs.
Lv, Zuobin (Tianjin Branch of CNOOC Ltd.) | Huo, Chunliang (Tianjin Branch of CNOOC Ltd.) | Ge, Lizhen (Tianjin Branch of CNOOC Ltd.) | Xu, Jing (Tianjin Branch of CNOOC Ltd.) | Zhu, Zhiqiang (Tianjin Branch of CNOOC Ltd.)
JZS oilfield is an offshore metamorphic rock fractured buried hill oilfield. It was put into development in July 2010. The overall production situation of the oilfield is good, but some problems have been exposed. The main performance is as follows: It is difficult to accurately characterize the heterogeneity of fracture space distribution; In the numerical simulation of fractured reservoir, it is impossible to accurately describe and predict the fracture flow of fluid channeling in corner point grid system.
In order to solve the above problems, this study presents a new integrated fractured reservoir geological modeling and numerical simulation research method based on unstructured grid. There are three key aspects to this method. (1) The multi-scale (large, middle and small) discrete fracture system is established by combining outcrop measurement data with well point information and seismic attributes. On the basis of post-stack 3D seismic data, ants attributes are extracted, then the ant body results are transformed into large scale fractures; Using azimuth anisotropy attribute based on pre-stack inversion and combining the distribution orientation of large-scale fractures, the middle-scale fractures are established; According to the power law distribution relation between the cumulative frequency and the fracture length of large scale and small scale which based on outcrop observation, the imaging logging data and pre-stack inversion azimuth anisotropy attribute, small scale fractures are constructed by DFN technology.(2) For multi-scale fractures, the unstructured grid division technique is used to build a 3D model that conforms to the heterogeneity of dual media. In this study, a layered triangular prism grid generation technique is proposed. It is used to establish model of multi-scale fractures based on unstructured grid. Using large-scale fractures as a constraint, full 3D unstructured grid model is set up, and the discrete fracture model can accurately describe the fracture system and the coupling relationship between matrix and the fracture;(3)The triple-medium numerical simulation of the reservoir in the study area is carried out by using the automatic history fitting technology of ensemble kalman filter (EnKF). After several parameter adjustments, both the coincidence rate of the index and the fitting precision are higher than before.
Multi-scale discrete fracture model based on the large-scale fractures discretization processing, equivalent medium processing to middle and small scale fractures, keeps the seepage characteristic of the large-scale discrete fractures model and ensures the calculation efficiency. The results show that the new method has obvious advantages in computing speed and that the fitting effect is closer to the actual production performance.
Is Surfactant Environmentally Safe for Offshore Use and Discharge? The current presentation date and time shown is a TENTATIVE schedule. The final/confirm presentation schedule will be notified/available in February 2019. Designing Cement Jobs for Success - Get It Right the First Time! Connected Reservoir Regions Map Created From Time-Lapse Pressure Data Shows Similarity to Other Reservoir Quality Maps in a Heterogeneous Carbonate Reservoir. X. Du, Y. Jin, X. Wu, U. of Houston; Y. Liu, X. Wu, O. Awan, J. Roth, K.C. See, N. Tognini, Shell Intl.
By International Petroleum Technology Conference (IPTC) Monday, 25 March 0900-1600 hours Instructors: Olivier Dubrule and Lukas Mosser, Imperial College London Deep Learning (DL) is already bringing game-changing applications to the petroleum industry, and this is certainly the beginning of an enduring trend. Many petroleum engineers and geoscientists are interested to know more about DL but are not sure where to start. This one-day course aims to provide this introduction. The first half of the course presents the formalism of Logistic Regression, Neural Networks and Convolutional Neural Networks and some of their applications. Much of the standard terminology used in DL applications is also presented. In the afternoon, the online environment associated with DL is discussed, from Python libraries to software repositories, including useful websites and big datasets. The last part of the course is spent discussing the most promising subsurface applications of DL.
A large number of laboratory experiments about the influence of heating or heating-cooling cycles on the mechanical properties of various granites are reviewed. Both scanning electron microscopy (SEM) and particle-based discrete element modeling (DEM) are employed to quantitatively elucidate the mechanisms responsible for temperature-dependent mechanical properties of granites, from a perspective of microcracking. Both SEM observations and DEM simulations give consistent results and show that there exists a temperature threshold beyond which the thermally-induced microcracks increase drastically. Both intergranular and intragranular microcracks are observed in the granites after thermal treatment, and intergranular ones are dominant. A continuous increase in temperature can generally weaken granites, mainly by inducing significant thermal stress and generating tensile microcracks. The weakening of granites after a heating-cooling cycle is due only to the thermally induced microcracks. With increasing grain size the magnitude of Brazilian tensile strength reduction of granites due to thermal treatments becomes small, whereas with increasing heterogeneity in grain size distribution, the magnitude of Brazilian tensile strength reduction of granites due to thermal treatments becomes great. This is because the two competing mechanisms, i.e., the length and number of the thermally induced microcracks in granites.
Since the first enhanced geothermal system (EGS) was conceived at the Fenton Hill project, the United States, in the 1970s, EGS projects have been pursued around the world (McClure and Horne, 2014). EGS projects involve finding vast blocks with high temperature (> ~200 °C) and connected fracture networks. Working fluid (e.g., water or supercritical CO2) is first injected and circulated through the fracture networks in geothermal reservoirs and eventually pumped back to the surface as steam. In the world EGS projects are commonly located in granite rocks with various mineralogical properties (Zhao et al. 2018). The mechanical response of “hot granites” to cooling becomes an important question to geologists and engineers.
Summary Developments in instrumentation and processing tools have made 3D resistivity surveys an effective approach in delineating complex geological environments. In the performance of these surveys a large number of data points are produced, and the properties of the dataset should be explored to optimize and coordinate interpretation efforts. In this study, a field 3D dataset was geometrically decomposed into near maximum-coupled (so-called radial) and near null-coupled (so-called tangential) subsets and inverted using a 3D approach. The results indicate that these two models may represent the subsurface at regional and local scales and help in the discrimination of different targets. Introduction Mineral exploration generally employs the DC resistivity method to detect and map targets of interest.
The basement hydrocarbon reservoirs have been discovered in a lot of places over the world. The remarkable characteristics of the basement reservoirs are their low pressure with narrow density windows and well developed fractures which usually resulted in probably massive losses. A case study on drilling of fractured granitic basement with application of UBD in Chad and MPD in Indonesia is presented in this paper.
To tackle the common problems of drilling in narrow density windows and potential problem of losses, an underbalanced drilling (UBD) technology with a micro-foam drilling fluid was used in Chad. The pore pressure coefficient of the basement of Chad was predicted as between 1.02-1.06, and the density of the micro-foam drilling fluid was designed to be 8.7ppg. While an under-balanced managed pressure drilling (MPD) technology with a synthetic based gas-to-liquid (GTL) drilling fluid was utilized in Indonesia. The formation pressure coefficient of the basement of Indonesia was estimated to be 1.04, and the density of the GTL drilling fluid was designed to be 7.4ppg.
Losses or severe losses existed in previous conventional near-balanced drilling in fractured granitic basement of buried hills of Chad. The problem of losses also encountered even UBD was later used. Losses and kicks continued almost all the time during drilling, coring and wireline logging in some wells. Losses happened as soon as pump started while overflow occurred no sooner than pump stopped. However, the potential problem of losses and kicks was completely controlled by utilization of under-balanced MPD technology in fractured granitic basement of Indonesia.
The under-balanced MPD technology, a precisely pressure controlled drilling system, is able to accurately control the annular pressure profile throughout the wellbore, therefore it could effectively achieve safe drilling in narrow density window and cut non-production time. It is proved to be effective in drilling of fractured granitic basement.
The Australian geothermal energy sector has undergone a boom and bust cycle since the early 2000's. In contrast to the absence of large-scale electricity generation, the development of direct use resources, particularly in Perth, Western Australia, has proved to be quite successful, reaching a total of almost 15 MWth by end 2015 and a projection of 18–20 MWth by end 2016, and the once negligible small-scale off-grid power generation is getting momentum. The contrasting fate of the large-scale geothermal electricity and direct use sectors provides valuable insights into the importance of reservoir quality in the development of these resources.
An entire energy value chain review of a dozen operating direct-use geothermal projects in Perth, was conducted to identify success factors for direct use projects. The review has identified that: Extensive exploration and production of groundwater resources for water supply from depths of up to 1100 m contributed to a major decrease on reservoir quality risk, Operating and planned project requirements range from 0.5 to 3.3 MWth and target a relatively shallow resource (less than 1500 m deep), The geothermal resource has very good reservoir quality, so that performances are above world average (permeability thickness from 50 to over 1000 Dm and coefficient of performance in the order of 20 to 35) Injection difficulties which have been experienced in other similar overseas projects have been largely avoided and overcome in Perth, Perth geothermal projects are well established, economically viable, competitive with other energy sources and environmentally sustainable.
Extensive exploration and production of groundwater resources for water supply from depths of up to 1100 m contributed to a major decrease on reservoir quality risk,
Operating and planned project requirements range from 0.5 to 3.3 MWth and target a relatively shallow resource (less than 1500 m deep),
The geothermal resource has very good reservoir quality, so that performances are above world average (permeability thickness from 50 to over 1000 Dm and coefficient of performance in the order of 20 to 35)
Injection difficulties which have been experienced in other similar overseas projects have been largely avoided and overcome in Perth,
Perth geothermal projects are well established, economically viable, competitive with other energy sources and environmentally sustainable.
A forensic analysis of two geothermal wells drilled in the Cooper and Otway basins targeting high temperature electricity generation within sedimentary basins was performed to identify key issues associated with deeper targeting and large scale geothermal development. The forensic analysis highlights the importance of reservoir quality rather than high temperature targeting in sedimentary basins.
Finally, the results of a technico-economics analysis for large scale electricity generation enabled to identify key production parameters and limiting factors. The economics analysis shows that high well productivity (permeability thickness and flow rate above 50 Dm and 55,000 bblpd) is required at high temperatures (>120 °C) for large scale electricity generation. Destruction of permeability through diagenesis at these temperatures such as observed in one of the unsuccessful well may limit the likelihood of finding such high productivity reservoirs. There are also potential issues of the high flow rates required in terms of fine migration, well completion and pump design.
Ultimately it is the technical performance that controls the economic viability of these projects. With the necessary increase of energy delivery, new projects will need to investigate smart ways to achieve high flow rates, while limiting potential negative impacts in terms of fine migration and pressure losses.
This theoretical study about the development of a turbidite reservoir is unique because it considers the combination of the surface and the health, safety, and environment (HSE) constraints of the urban overlying the reservoir. Although geology poses deep challenges in terms of reservoir heterogeneity, anisotropy, compartmentalization, and pressure drives, the attempt to develop oil fields in an urban environment makes it very difficult to plan facilities, transport, services, and operations because of HSE issues. This study is a continuation of a previous study in which the background, modeling, and economic analysis of the earlier study is combined with stronger HSE concepts to make the study more holistic.
With a strong focus on health and environment, this paper establishes guidelines for managing the risks of urban development. Reservoir management is guided by sensitivities and uncertainties on CAPEX and OPEX, establishing novel ways of optimizing infill well locations, drilling practices in a city, and enhancing hydrocarbon production through reservoir simulation practices. The geological, geophysical, and engineering data for the study are generated to represent analogous turbidite reservoirs whereas the HSE well planning recommendations are derived from urban oilfield developments in Los Angeles and Long Beach, California.
The methodology of dynamic modeling is nonconventional in terms of analyzing the field for forecasting immediately after initialization followed by a detailed history match considering the numerous hurdles of turbidite environment. This allows greater time for field development planning, which is conventionally given the least attention because of time constraints. Therefore, the prediction comprises a no-further-action case, an infill wells case, and waterflood scenarios, with a combination of vertical and horizontal well trajectories exhibiting the best output in a span of vast economic sensitivities over multiple scenarios. The most noticeable part of the study is the wide range of realizations on well trajectories, well placement, optimizing drilling, and production services. Our modeled city was Houston, Texas, a well-known urban environment. As a result of the modeling, a technique was developed to guide for environmentally safe development within this example.
The technological and economic conclusions make this a foundation study for profitable development of reservoirs underneath a populated area. The study may also be instrumental in exploitation of turbidite reservoirs, which present challenges in current North Sea and Brazil offshore development and in recently discovered submarine fans in the Gulf of Mexico deep marine environment.