Lacustrine Shale Gas Reservoir Characterization in the Yanchang Formation by Integrated Geological Facies, Geochemistry, Chemostratigraphy, SEM Pore Imaging, Petrography, and Geophysics

During the past 2 years, researchers from the Bureau of Economic Geology (BEG) and Yanchang Petroleum Group (Yanchang) have worked closely to conduct an integrated research project titled "Lacustrine Shale Gas Reservoir Characterization in the Yanchang Formation by Integrated Geological Facies, Geochemistry, Chemostratigraphy, SEM Pore Imaging, Petrography, and Geophysics." On November 8, 2013, a team of executives, led by Dr. Xiangzeng Wang, Vice President and Chief Geologist of the Shaanxi Yanchang Petroleum Company, Ltd., visited the Bureau of Economic Geology (BEG) to sign a 2-year agreement for the project. Project objectives were to provide integrated studies of geological facies, hydrocarbon geochemical characterization, chemical stratigraphy, SEM pore imaging, and detailed petrographic study. These aspects were to be integrated to yield broader concepts about hydrocarbon generation and storage and the distribution of geological facies and fundamental rock attributes. Additionally, models were to be developed for evaluating sweet spots for shale gas that can be applied in making economic decisions. All project tasks have been on schedule, and collaboration between the BEG and Yanchang Petroleum has been very successful. A team of executives, led by Dr. Xiangzeng Wang, Vice President of the Shaanxi Yanchang Petroleum Company, Ltd., traveled to Austin twice during the research project for midterm and final project reviews. The Research Institute of Shaanxi Yanchang Petroleum sent five researchers to the BEG who were involved in specific research tasks relevant to their backgrounds and interests. A team of BEG researchers led by Dr. Scott Tinker, BEG Director; Eric Potter, BEG Energy Program Manager; and Drs. Tongwei Zhang and Hongliu Zeng, Principal Investigators (PIs) of the research project, traveled to Xi'an three times to conduct core description, data collection, and sampling. A field trip to Yanchang Formation outcrops took place during one visit, and presentations were given at the year-1 project review meeting and at the final project review meeting. BEG researchers also conducted a series of technology-transfer workshops at The Research Institute of Shaanxi Yanchang Petroleum. A large amount of new data collection has been conducted during the 2 years of the project. More than 60,000 raw data for 23 new analytical items are summarized in Table 1: 15 GB of petrographic data, 25 GB of SEM pore imaging data, and 216 core pictures were collected. Twenty oral presentations, nine poster presentations, three reports, and five abstracts were given in annual and final project review meetings (Table 2). Key results will be published in Interpretation, in a Special Section titled "Lacustrine shale characterization and shale resource potential in Ordos Basin, China," in May 2017.Bureau of Economic Geolog

Comparing carbon sequestration in an oil reservoir to sequestration in a brine formation-field study

Geologic sequestration of CO2 in an oil reservoir is generally considered a different class than sequestration in formations which contain only brine. In this paper, the significance and validity of this conceptualization is examined by comparing the performance of CO2 injected into a depleted oil reservoir with the performance of similar injection into non-oil bearing sandstones using a field test at Cranfield Field, Mississippi as a case study. The differences considered are: (1)Residual oil in the reservoir slightly reduces the CO2 breakthrough time and rate of pressure build up as compared to a reservoir containing only brine, because under miscible conditions, more CO2 dissolves into oil than in to brine. (2)Dense wells provide improved assessment of the oil reservoir quality leading to improved prediction as well as verification of CO2 movement in this reservoir as compared to the sparsely characterized brine leg. The value of this information exceeds the risk of leakage. Assessment of the difference made by the presence of residual oil requires a good understanding reservoir properties to predict oil and gas distribution. Stratal slicing, attribute analysis and petrographic analyses are used to define the reservoir architecture. Real-time pressure response at a dedicated observation well and episodic pressure mapping has been conducted in the reservoir under flood since mid-2008; comparison measurements are planned for 2009 in down-dip environments lacking hydrocarbons. Model results using GEM compositional simulator compare well in general to measured reservoir response under CO2 flood; imperfections in model match of flood history document uncertainties Time laps RST logging is underway to validate fluid composition and migration models. Monitoring assessing the performance of the wells during the injection of CO2 suggests that the value of wells to provide field data for characterization exceeds the risk of leakage.Bureau of Economic Geolog

Targeting reserve growth opportunities in the northern Gulf of Mexico Basin: transferring secondary gas recovery technology to the offshore environment - book 2

The Bureau of Economic Geology's (BEG) Offshore Secondary Gas Recovery is a multi-fiscal-year project funded by the U.S. Department of Energy, whose goal is to research new techniques for defining the structure, stratigraphy, and hydrocarbons in a mature area in the northern Gulf of Mexico and to utilize those multidisciplinary methods to identify additional gas resources, as well as predict regional trends in hydrocarbon accumulation. Phases 1 and 2 of the project work plan (Project Preparation and Data Gathering and Loading, respectively) are completed. Phase 3 of the plan (Data Analysis) is 65 percent completed, with all third- and fourth-order key surfaces mapped in the log data. Sixty fourth-order and twelve third-order sequences have been defined using well data, and key flooding surfaces have been mapped in the seismic volume. Structural mapping of 13 key horizons is completed and provides a structural framework within which to look at production and reservoir development. The sequence framework is complete within and immediately between the two fields and provides a basis for examining hydrocarbon occurrence and distribution. Structural slices of the seismic amplitude data volume have been completed at 4-ms intervals through the data, providing detailed maps of amplitude anomalies associated with quality reservoirs. The process of transforming the seismic attribute volume into a three-dimensional petrophysical volume is progressing, and the addition of an engineer in FY 2001 will initiate development of a fourth-order-level reservoir-flow model within a carefully chosen subset of the data volume.Bureau of Economic Geolog

Metastasis of human gastric adenocarcinoma partly depends on phosphoinositide-specific phospholipase γ1 expression

It is known that phosphoinositide-specific phospholipases γ1(PLCγ1) can trigger several signalling pathways to regulate cell proliferation, differentiation, and metastasis. However, whether this kinase is highly expressive and active in human gastric adenocarcinomas, and whether it can play an important role in the development of the cancer, have not yet been investigated. The aim of the study was to investigate the expression of PLCγ1 in human gastric adenocarcinoma, while the question of whether PLCγ1 can be activated through protein kinase B (Akt) signalling pathways to regulate cell migration was further explored using human gastric adenocarcinoma BGC-823 cell line. The expression of PLCγ1 in human adenocarcinoma was detected using immunohistochemical staining. The BGC-823 cells were cultured and treated with inhibitors or transfected with plasmid construction. The cell migration of BGC-823 cells was measured with wound healing assay, cell migration assay, and the ruffling assay. The expression levels of PLCγ1 and its related signal molecules in BGC-823 cells were assessed using Western blot analysis or gelatine zymography assay. PLCγ1 was highly expressed in humangastric adenocarcinomas, especially in the region with lymph node metastasis. It was shown that migration of BGC-823 cells in vitro depends on PLCγ1 activation. This activation is mediated through Akt, an upstream of PLCγ1 that triggers the PLCγ1/extracellular signal-regulated kinase (ERK)/matrix metalloproteinase (MMP) pathway in BGC-823 cells. PLCγ1 activities play an important role in the metastasis of gastric adenocarcinoma, and may serve as a potential therapeutic target in this type of cancer

Targeting reserve growth opportunities in the northern Gulf of Mexico Basin: transferring secondary gas recovery technology to the offshore environment Book 1

The Bureau of Economic Geology's Offshore Secondary Gas Recovery project is a multi-fiscal-year project funded by the U.S. Department of Energy, whose goal is to identify additional natural gas resources in a major field in the northern Gulf of Mexico Basin through multidisciplinary field and reservoir characterization study. Phases 1 and 2 of the project work plan (Project Preparation and Data Gathering and Loading, respectively) are nearly complete and scheduled to be completed by the end of October 1999. Phase 3 of the plan (Data Analysis) is well underway, and a list of preliminary leads is currently being compiled to convey to our industry partner. Reservoir tops have been spotted to facilitate production evaluation and recompletion opportunity. Key regional sequence surfaces have been identified in well logs and seismic, and mapping is being completed in the seismic dataset. Some of these surfaces have provided horizons to initiate a continuity processing of the seismic data volume for mapping depositional architecture. Well log interpretation of stacking patterns and systems tracts is well underway. Correlation surfaces have been compiled, and cross sections have been generated and interpreted for depositional elements. These data are being integrated with seismic data via Landmark® software. The project is on track within its projected timeframe, and additional personnel are being added as per the technical analysis plan. The key objective in the next fiscal year is to do the bulk of the technical analysis, focusing on generating a prioritized portfolio of infill and exploration prospects. Direct hydrocarbon indicator (DHI) modeling and analysis, continuity and impedance analysis, a general attribute interpretation of the seismic data, continued log-facies and parasequence interpretation, fault-seal analysis, and rigorous petrophysical analysis of well data are critical components of this objective.Bureau of Economic Geolog

Post-treatment neutrophil-lymphocyte ratio independently predicts amputation in critical limb ischemia without operation

OBJECTIVES: Limited information is available concerning the post-treatment neutrophil-lymphocyte ratio in critical limb ischemia patients who receive conservative therapy. Accordingly, this study was designed to evaluate the predictive value of the post-treatment neutrophil-lymphocyte ratio in critical limb ischemia patients without surgery. METHOD: From January 2009 to January 2011, critical limb ischemia patients were admitted to a vascular center. The demographic data, patient histories, comorbidities and risk factors were documented, and the differential cell count was determined at admission and seven days later after conservative therapy. The cutoff value of the post-treatment neutrophil-lymphocyte ratio was determined by an ROC curve. Patients were divided into groups A and B according to the cutoff value. Amputation-free survival was compared between groups. Univariate and multivariate analyses were used to identify independent risk factors. RESULT: A total of 172 patients were identified with a mean age 71.98±10.09 years; among them, 122 were male. A value of 3.8 was identified as the cutoff value of the post-treatment neutrophil-lymphocyte ratio. Groups A (post-treatment neutrophil-lymphocyte ratio ≥3.8) and B (post-treatment neutrophil-lymphocyte rati

Facies-guided 3-dimensional seismic modeling and reservoir characterization

A set of 3-D seismic models has been generated for a lower Miocene progradational micro-tidal shore-zone system at Powderhorn field, Calhoun County, Texas. These models are based on detailed mapping of facies and rock-properties that involves 250 m of stratigraphic section over an area of 13 by 9 km. Examination of logs from 115 wells shows that fourteen sandy depositional units averaging 3-30 m in thickness are encased in 15 shale units. Effective porosity, P-wave velocity and bulk density are calculated from suites of wireline logs in five recent wells, and then expanded to older wells through regression with SP and resistivity logs. Property mapping in two dimensions is accomplished by employing the directional weighted average method (DWA), which simulates the hand mapping of a geoscientist by incorporating the directional and geometrical information gained from facies analysis into gridding. This biased mapping approach produces a striking visual impact compared to unbiased computer mapping. A predictogram analysis also confirmed that DWA is better than other computer algorithms for generating sandstone thickness maps, though rock-property pedictions were not improved. The predictogram measures information content of both wells and seismic data, and can help to explain the mistie between synthetic and real seismic traces at well locations. Idealized 3-dimensional seismic models are generated by convolving a Ricker wavelet with the primary reflection coefficient series from stacked 2-D P-wave velocity and impedance models. The idealized stratal slices show that to achieve the best image of depositional facies, seismic frequency should be tuned to the maximum sandstone thickness. Framework sand bodies surrounded by muddy deposits are well illustrated. Clean sandstone and pure shale have similar impedance, creating ambiguous amplitude patterns. The stratal resolution of seismic imagery depends not only on wavelet frequency, but also on the magnitude of geological interference. This 3-D model also provides a realistic basis for evaluating the expected hydrocarbon detectability for the reservoirs in this evironment. Examples illustrate that the presence of gas should produce stratal slice amplitude anomalies that are very large compared to the facies-related amplitude variations. Seismic events do not necessarily follow geological time lines. The correlation error of peak picking is often large enough to distort reservoir facies image on stratal slices. In some cases, event crossing connects sand bodies from different units to form a new event. An event tying as many as six depositional units over 50 m has been observed. Phantom mapping produces truer stratal slices, making it possible to map detailed depositional facies within reservoir sequences from 3-D seismic dataGeological Science