Major Sandstone Units Research Articles

WELL LOGGING AND ELECTROFACIES OF ZUBAIR FORMATION FOR UPPER SANDSTONE MEMBER IN ZUBAIR OIL FIELD, SOUTHERN IRAQ

The Lower Cretaceous Zubair reservoir is a main producing horizon in the Zubair oil Field, southern Iraq. The reservoir consists of a number of isolated vertical major sandstone units. Sedimentary characteristics can be determined using the well log data as one of the most fundamental methods for reservoir characterization in the oil and gas industry. The reading of high gamma-ray response indicates the presence of shale which contains clay minerals, K-feldspar, and organic material that emits natural gamma radiation. The clean sandstones emit less radiation so it has a lower gamma-ray count analysis. Five of electrofacies were identified in the upper sandstone member of Zubair formation in Zubair oil field, in more details H layer divided into three sub-units. Zubair formation delta deposited through sea regression followed by sea progression because shelf facies overlies other delta facies as shown H layer between K and C units both were shale rocks. Porosity and permeability of the upper sandstone member of Zubair Formation were identified in twenty oil-wells. The relationship between the porosity and permeability after correction with data obtained from the core analysis data showed an improvement to the north part of the field precisely in Hammar-Shuaiba domes. On the other hand the grain sizes varied from coarse to medium; medium to fine in Hammar dome while fine to medium fine to very fine with clay influence led to a decrease the porosity and permeability thus reduced oil production.

Record of orogenic cyclicity in the Alberta foreland basin, Canadian Cordillera

Jurassic–Cretaceous sedimentary rocks of the Alberta foreland basin are a key record of the evolution of the Canadian Cordillera. We test a recent model for cyclical development of Cordilleran orogenic systems using detrital zircon analysis of the major sandstone units deposited between 145 and 80 Ma exposed in the Rocky Mountain Foothills near Grande Cache, Alberta. The basin history is well constrained by decades of study, and the stratigraphy has been previously subdivided into tectonostratigraphic wedges. U-Pb data from 14 detrital zircon samples are included in this study. All the major magmatic provinces of North America are represented in each sample, with the relative proportions varying between samples. The samples are assigned to five groups with the aid of multidimensional scaling. Groups 1–3 are interpreted to record recycling from specific passive-margin units of western North America with varying input from the Cordilleran magmatic arc. Group 4 is interpreted to record recycling from sedimentary strata in the United States and dispersal by basin-axial fluvial systems. Group 5 is dominated by Mesozoic zircon grains interpreted to have originated in the Cordilleran magmatic arc. Detrital zircon age spectra do not form groups based on the tectonostratigraphic wedges from which they were sampled; rather, within each tectonostratigraphic wedge, they exhibit evolution from diverse age spectra to a less-diverse distribution of detrital zircon ages.

Provenance history of the Bangemall Supergroup and implications for the Mesoproterozoic paleogeography of the West Australian Craton

The 4–10 km-thick Bangemall Supergroup, comprising the Edmund and Collier Groups, was deposited between 1620 and 1070 Ma in response to intracratonic extensional reactivation of the Paleoproterozoic compressional Capricorn Orogen. The supergroup can be further divided into six depositional packages bounded by unconformities or major marine flooding surfaces. U–Pb dating of over 1200 detrital zircon grains from 19 samples representative of each of the major sandstone units within these packages has failed to identify any zircon populations attributable to syndepositional magmatism. However, this extensive dataset provides a provenance history of the Bangemall Supergroup, which is here integrated with paleocurrent data which indicates that all source areas were located within the Mesoproterozoic West Australian Craton, with the main source area for the northern Bangemall Supergroup being the Gascoyne Complex and southern Pilbara Craton. All samples have prominent age modes in the 1850–1600 Ma range, indicating significant contribution from the northern Gascoyne Complex and coeval sedimentary basins. Some samples also display prominent modes in the 2780–2450 Ma range, consistent with derivation from the Fortescue and Hamersley Groups of the southern Pilbara Craton. The Edmund Group has age-spectra in which the dominant modes become older upwards, recording unroofing of the underlying basement from the Gascoyne Complex to the Archean granites and greenstones of the Pilbara Craton. In contrast, the Collier Group records unroofing of the underlying Edmund Group, with possible additional contribution from the Pilbara Craton and Paterson Orogen, and is characterized by age-spectra in which the dominant modes become younger upwards. These data imply that the West Australian Craton remained intact throughout the Mesoproterozoic assembly of Rodinia, and was the only source of detritus for the Bangemall Supergroup.

Tectonic deformation and its sedimentary consequences during deposition of the Lower Cretaceous Chaswood Formation, Elmsvale basin, Nova Scotia

Research Article| June 01, 2005 Tectonic deformation and its sedimentary consequences during deposition of the Lower Cretaceous Chaswood Formation, Elmsvale basin, Nova Scotia David J.W. Piper; David J.W. Piper Geological Survey of Canada (Atlantic), Bedford Institute of Oceanography, P.O. Box 1006, Dartmouth, NS B2Y 4A2 Search for other works by this author on: GSW Google Scholar Georgia Pe-Piper; Georgia Pe-Piper Department of Geology, Saint Mary’s University, Halifax, NS B3H 3C3 Search for other works by this author on: GSW Google Scholar Ernest V. Douglas Ernest V. Douglas Department of Geology, Saint Mary’s University, Halifax, NS B3H 3C3 Search for other works by this author on: GSW Google Scholar Author and Article Information David J.W. Piper Geological Survey of Canada (Atlantic), Bedford Institute of Oceanography, P.O. Box 1006, Dartmouth, NS B2Y 4A2 Georgia Pe-Piper Department of Geology, Saint Mary’s University, Halifax, NS B3H 3C3 Ernest V. Douglas Department of Geology, Saint Mary’s University, Halifax, NS B3H 3C3 Publisher: Canadian Society of Petroleum Geologists Received: 31 Aug 2004 Accepted: 10 Jan 2005 First Online: 02 Mar 2017 Online ISSN: 2368-0261 Print ISSN: 0007-4802 © The Society of Canadian Petroleum Geologists Bulletin of Canadian Petroleum Geology (2005) 53 (2): 189–199. https://doi.org/10.2113/53.2.189 Article history Received: 31 Aug 2004 Accepted: 10 Jan 2005 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation David J.W. Piper, Georgia Pe-Piper, Ernest V. Douglas; Tectonic deformation and its sedimentary consequences during deposition of the Lower Cretaceous Chaswood Formation, Elmsvale basin, Nova Scotia. Bulletin of Canadian Petroleum Geology 2005;; 53 (2): 189–199. doi: https://doi.org/10.2113/53.2.189 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyBulletin of Canadian Petroleum Geology Search Advanced Search Abstract The Lower Cretaceous fluvial Chaswood Formation is the proximal onshore equivalent of deltaic deposits of the Missisauga and lower Logan Canyon formations of the offshore Scotian basin. Detailed description of boreholes and analysis of published seismic-reflection profiles from the Elmsvale basin show that syn-sedimentary deformation in the Chaswood Formation resulted in onlap and unconformities. Deformation was concentrated in a syncline bounded on its northwestern side by the Rutherford Road fault. The deformation was probably synchronous along the 15 km length of the fault and might thus provide a basis for stratigraphic correlation. Closely spaced boreholes show that lignite horizons are not widespread stratigraphic markers and that major sandstone units are of more value for correlation. A new correlation from the type section of the Chaswood Formation northeastward along the Elmsvale basin and northwestward to Shubenacadie is proposed. A landslide deposit up to 5 m thick consisting of tilted mudstone blocks can be correlated for 4 km along strike in boreholes along the northern flank of the syncline, providing further evidence for syn-sedimentary deformation, which is a local manifestation of widespread Cretaceous deformation in Atlantic Canada. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

A Preliminary Study Of The Hibernia Field

Abstract The Government of Newfoundland and Labrador Petroleum Directorate, in conjunction with INTERCOMP has conducted a preliminary investigation of various depletion schemes for the Avalon and Hibernia reservoirs within the Hibernia Field. Five wells have been drilled in this field to date which confirm the existence of substantial quantities of oil and gas reserves in at least two major reservoirs. A description of each reservoir was based on interpretation of the existing seismic. geological, petro physical and production test data. Reservoir simulation models were constructed for each reservoir to examine the effect of various recovery mechanisms. The results presented in this study are considered to represent only a minimal degree of optimization due to the limited reservoir description presently available. This paper focuses on the results of the reservoir simulation study. A brief description of the major geological and fluid characteristics and a discussion of the impact of these characteristics on depletion strategies for each reservoir are provided. In addition, the major uncertainties and potential problem areas which may require further investigations are identified. The simulation results with respect to production rates and recovery are also presented for typical development strategies for each reservoir. Preliminary studies of this nature are considered as the beginning of a series of progressively more complex studies which are essential to the efficient and optimum development of offshore reservoirs. Introduction The Hibernia Field is located approximately 320 km southeast of St. John's, Newfoundland, as shown in Figure 1. The water depth in this region is approximately 80 metres. The Hibernia Field was discovered in September 1979 with the drilling and completion of the well Chevron et al. Hibernia P-15. Four subsequent wells Mobil et al. Hibernia 0-35, B-08, G-55A, and K-18 have been drilled confirming the existence of major hydrocarbon-bearing sandstone units in sediments of Jurassic and Lower Cretaceous age. These major sandstone units have been identified as the Jeanne d'Arc zone in the Jurassic sands, and the Hibernia, Avalon and the Seismic B-Marker (Catalina) zones in the Lower Cretaceous sands. The potential hydrocarbon-bearing zones encountered in each of the wells are summarized in Table 1. F1GURE 1. Hibernia Field location.(Available in full paper) TABLE 1. Summary of hydrocarbon-bearing zones-Hibernia Field (Available in full paper) Productivity potentials of 2485–3180 m3/D per well have been indicated based on the drill-stem tests results from the wells P-15 and O-35. The differences in reservoir development encountered in the five wells confirm that the hydrocarbon accumulation consists of multiple, possibly non-communicating, sand layers within a complex structure that is folded and faulted. Based on the results of the five wells, the majority of the hydrocarbon reserves are interpreted to be located in the Avalon and Hibernia reservoirs. The subject matter of this paper is therefore based on a study of these two reservoirs. As the title of the study suggests results and conclusions presented herein are preliminary. The subject study includes data which were available on April 30, 1981 and does not include data acquired from Mobil et al. Hibernia K-18 and J-34 or the 3-D seismic program.

Persimmon Creek Field--Anatomy of a Morrow Stratigraphic Trap: ABSTRACT

Persimmon Creek field in T20N, R22W, Woodward County, Oklahoma, on the northern shelf of the Anadarko basin, produces gas and condensate from upper lower Morrow sandstone. The field occurs above a prominent southward-plunging structural nose on the Chester limestone. This and similar noses nearby appear to be paleotopographic highs that strongly influenced subsequent Morrow deposition. A thicker Morrow section overlies Chester lows or paleovalleys and a thinner sequence occurs above the noses. In this area, the Morrow contains an upper shale section and a lower sand-shale sequence containing four major sandstone units, each of which may contain one or more discrete sandstone beds with interbedded shale. The basal Morrow Hamilton sandstone strikes west-northwest, but filling of the subjacent Chester paleovalleys has caused local thicker sand accumulations with good porosity to trend north-south. The overlying Yellow sandstone has similar characteristics. In the Brown sandstone, this relationship is reversed, and the thickest sand accumulation and best porosity development occur above the plunging Chester noses. The uppermost Fritzler sandstone is more erratic in character, showing little relationship to Chester paleotopography. End_Page 641------------------------------ Persimmon Creek field, with an area of about 2 mi2, produces from north-south-trending Brown sand bars 8 to 20 ft (2.4 to 6 m) thick with 14 to 22% porosity. By analogy, in this part of the Anadarko basin, Morrow exploration should focus on locating porous upper lower Morrow sandstone above basinward-plunging Chester noses. End_of_Article - Last_Page 642------------

Flow-system controls of the chemical evolution of groundwater

Isotopic and major-ion analyses of 130 fresh and brackish groundwater samples reveal a strikingly consistent pattern of variation over 28,000 km 2 of the western Canada sedimentary basin. Hydrodynamic interpretations based on drill-stem tests and piezometric data reveal a pattern of broad, regional flow from south to north. However, there is some evidence to suggest that patterns of groundwater flow have been influenced in the past by Wisconsin glaciation. All the permeable units appear to be recharged by meteoric water in the south where they outcrop or come close to the surface. Samples of groundwater collected down dip in each of six major sandstone units are progressively enriched in D, 18O, Na + and Cl −. For example, the deepest waters of the artesian Milk River aquifer are enriched by up to 70‰ and 15‰ with respect to the δD and δ 18O of the modern recharge waters. The pattern of chemical evolution is strongly related to the hydraulic characteristics of individual units. The isotopic composition is determined by the extent to which hydraulic conductivity has facilitated meteoric water flushing of connate water. Thus, more permeable units and permeable zones within a unit tend to be isotopically lighter because of a more complete and more rapid invasion of meteoric water. Interestingly, the largest conductivity values are found in some of the deepest units (1500 m). Consequently, water in these deeper units have δD- and δ 18O-values which approach that of the recharge. The major-ion chemistry is controlled both by this process and a complex set of rock-water interactions. In addition to providing information about the chemical evolution of groundwater, this study can begin to quantify the complex pattern of flushing in a large sedimentary basin.

Description and Sedimentology of Submarine-Fan Gas Reservoir in Woodbine-Eagle Ford Interval (Upper Cretaceous), Sugar Creek Field, Tyler County, Texas: ABSTRACT

Abundant gas and some condensate are being produced from fractured sandstones of the Upper Cretaceous Woodbine-Eagle Ford interval at depths of 10,800 to 11,350 ft (3,240 to 3,405 m) in the Sugar Creek field area of Tyler County, Texas. The reservoir sandstone units are complex, single to multiple bodies 15 to 40 ft (4.5 to 12 m) thick and less than a few thousand feet wide within a mud-dominated clastic wedge. The wedge thickens from about 50 ft (15 m) near the Lower Cretaceous shelf edge to more than 1,500 ft (450 m) within 15 mi (24 km) downdip to the south. Subsurface correlation and mapping of the discontinuous, lenticular sandstone bodies indicate that they are best delineated as a series of coalescing, dip-oriented lobes. Deposition appears most likely to have been as prograding submarine-fan lobes, with sediment being channeled from updip delta and nearshore deposits across a narrow shelf and through shelf-edge breaks and then dumped downslope. Within the major sandstone units, individual beds commonly are 1 to 3 ft (0.3 to 1 m) thick and display sharp contacts with interbedded, thin (1 to 2 in.; 2.5 to 5 cm) shale layers. As viewed in polished core slabs, the sandstones are mostly massive; however, radiography reveals abundant lamination and cross-stratification and some ripple-bedding and soft-sediment-deformation structures. A detailed analysis of sedimentary features and sandstone fabric suggests periodic rapid End_Page 528------------------------------ deposition of sand by low-concentration to high-concentration, submarine density currents and associated tractive currents. The fine to very fine-grained sandstones are well-cemented quartz arenites with porosities commonly 10 to 15% and permeabilities commonly around 0.1 to 1.0 md. Abundant fractures in the brittle sandstone provide the necessary reservoir permeability to allow commercial gas production. End_of_Article - Last_Page 529------------

The magnetic polarity stratigraphy and age of the Siwalik group near Dhok Pathan village, Potwar Plateau, Pakistan

The magnetic polarity zonation of the terrestrial strata exposed in the Dhok Pathan area of Pakistan has been established utilizing data from 204 paleomagnetic sites. Individual magnetic transitions are traced laterally over 15 km and provide convenient time lines for correlating the fluvial facies of the middle Siwalik Group. A pervasive, normal polarity zone dominates throughout the region and has been interpreted as Magnetic Polarity Epoch 9. Based on this interpretation and using the absolute ages from the published magnetic time scales the average sedimentation rate in the area is calculated at 0.8 m/1000 years, and the average elapsed time between fluvial cycles is 56,000 years. Major sandstone units are minimally time transgressive in an east-west direction. The Nagri Formation in the Dhok Pathan area spans the time from 10.0 to 8.6 m.y. B.P. Ramapithecus and other hominoid primates are found in Epoch 9 at about 9 m.y.

DOLOMITIZED SANDSTONES: A MARLIN FIELD GAS-RESERVES ASSESSMENT PROBLEM

Dolomite cement had been recognised within fluvio-deltaic facies sandstones of the Gippsland Basin Marlin field N-1 (Eocene) gas reservoir in the initial wildcat and two stepout wells. Although initially thought to be insignificant, the additional control provided by development drilling indicated that the degree and extent of dolomite cementation within the reservoir sandstones could be wide-ranging enough significantly to reduce reserves and influence reservoir performance. A study to define the area and degree of dolomite cementation within the reservoir showed that the distribution pattern within the 5 major sandstone units fell into 3 distinct groups. Whereas the 3 stratigraphically oldest (N-1.5, N-1.4 and N-1.3) units were only dolomitized within the northeastern portion of the field area, the N-1.2 unit was dolomite cemented field-wide. The youngest (N-1.1) unit, which unconformably overlies the truncated N-1.2 unit, is devoid of significant dolomite influence.Dolomitization of the N-1 sandstone units is interpreted to have occurred during a phase of estuarine-restricted marine shale deposition which followed the truncation of the N-1.2 sandstone unit. Although these estuarine dolomitic shales are absent by erosion at Marlin, they are present in the adjacent Tuna field area. Distribution of the dolomite cement within the reservoir sandstones was controlled by the subcrop pattern of the sandstone units during the deposition of the estuarine sediments.Petrological and x-ray diffraction information strongly suggest primary dolomite cementation, and not dolomitization of some pre-existing carbonate cement. The petrological, core analysis and geological information was integrated with the interpretation of wireline porosity logs to obtain reservoir unit average porosities and calculate reserves.The currently estimated initial N-1 reservoir dry gas reserves are 2.72 TSCF. If the reservoir sandstones were not dolomite cemented, reserves would be 3.15 TSCF, that is 14% greater.