scholarly journals GEOLOGI DAN UBAHAN HIDROTERMAL SUMUR DANGKAL SWW-2 LAPANGAN PANAS BUMI SUWAWA, BONEBOLANGO - GORONTALO

1970 ◽  
Vol 2 (2) ◽  
pp. 14-22
Author(s):  
Fredi Nanlohi
Keyword(s):  
Cap Rock ◽  
Clay Cap

Stratigrafi sumur SWW-2 tersusun oleh endapan aluvial (0-50 m), endapan piroklastika (50-57,5 m) dan andesit terubah (57,5 – 250 m). Gejala struktur sesar ditemukan pada kedalaman 140-145 m dan 200-210 m dicirikan oleh adanya zona hancuran dan milonitisasi. Ubahan hidrotermal dengan intensitas kuat hingga sangat kuat mulai terjadi dari kedalaman 57,5 hingga kedalaman 250 m, disebabkan oleh proses argilitisasi, oksidasi, anhidritisasi dengan/tanpa kloritisasi, karbonatisasi, piritisasi, zeolitisasi ilitisasi dan epidotisasi. Pembentukan batuan ubahan sebagai hasil replacement dari mineral utama pada batuan dan matrik/masa dasar batuan, sebagian terbentuk sebagai urat -urat pengisi rekahan pada batuan (vein) dan vug (pengisi rongga pada batuan). Intensitas ubahan lemah hingga sangat kuat (Perbandingan mineral ubahan terhadap total mineral dalam batuan atau SM/TM= 20-85%). Epidot mulai ditemukan pada kedalaman 125 m, kehadirannya sebagai replacement ,terbentuk pada temperatur 230ºC dan sebagai vein serta vug terbentuk pada temperatur 260-280ºC. Biotit ditemukan dari kedalaman 100-200 m, dapat terbentuk pada 220 ºC hingga lebih dari 325ºC. Pembentukan mineral ubahan temperatur tinggi ini terjadi karena fluida panas bumi naik hingga kedalaman yang dangkal melalui rekahan -rekahan yang terbentuk oleh pergerakan sesar normal Lombongo dan Duano. Telah terjadi penurunan temperatur reservoir sejak pembentukan mineral temperatur tinggi tersebut disbanding dengankondisi temperature aktual sumur saat ini. Batuan dari kedalaman 0 – 57,5 m belum mengalami ubahan hidrotermal sampai terubah lemah bersifat sebagai lapisan penutup atau overburden. Dari kedalaman 57,5 – 90 m merupakan andesit terubah dengan tipe ubahan argilik berfungsi sebagai batuan penudung (cap rock/clay cap). Batuan dari kedalaman 90 – 125 m adalah andesit terubah dengan tipe ubahan phyllic merupakan zona transisi dan batuan dari kedalaman 125 – 250 m adalah batuan andesit terubah dengan tipe ubahan propylitic sebagai zona reservoir, dicirikan oleh kehadiran mineral epidot, zeolit, klorit, kuarsa dan mineral lainnya.

Investigation on the experimental determination of the apparent preconsolidation stress and effective-sealing condition for clay cap rock

2018 ◽  
Vol 11 (17) ◽  
Author(s):  
Jun-xin Liu ◽  
Feng Xiao ◽  
Wei Liu ◽  
Jian-jun Gan ◽  
Liang Huo ◽  
...  
Keyword(s):  
Experimental Determination ◽  
Cap Rock ◽  
Clay Cap

Ground penetrating radar imaging of cap rock, caliche and carbonate strata

2000 ◽  
Vol 43 (2-4) ◽  
pp. 239-249 ◽  
Author(s):  
S.E Kruse ◽  
J.C Schneider ◽  
D.J Campagna ◽  
J.A Inman ◽  
T.D Hickey
Keyword(s):  
Ground Penetrating Radar ◽  
Radar Imaging ◽  
Cap Rock ◽  
Ground Penetrating

Fracture mapping using seismic amplitude variation with offset and azimuth analysis at the Weyburn CO2 storage site

Geophysics ◽  
2012 ◽  
Vol 77 (6) ◽  
pp. B295-B306 ◽  
Author(s):  
Alexander Duxbury ◽  
Don White ◽  
Claire Samson ◽  
Stephen A. Hall ◽  
James Wookey ◽  
...  
Keyword(s):  
Cross Sections ◽  
Co2 Storage ◽  
Horizontal Stress ◽  
Storage Site ◽  
Fracture Zones ◽  
Amplitude Variation ◽  
Amplitude Variation With Offset ◽  
Seal Integrity ◽  
Cap Rock ◽  
Weyburn Field

Cap rock integrity is an essential characteristic of any reservoir to be used for long-term [Formula: see text] storage. Seismic AVOA (amplitude variation with offset and azimuth) techniques have been applied to map HTI anisotropy near the cap rock of the Weyburn field in southeast Saskatchewan, Canada, with the purpose of identifying potential fracture zones that may compromise seal integrity. This analysis, supported by modeling, observes the top of the regional seal (Watrous Formation) to have low levels of HTI anisotropy, whereas the reservoir cap rock (composite Midale Evaporite and Ratcliffe Beds) contains isolated areas of high intensity anisotropy, which may be fracture-related. Properties of the fracture fill and hydraulic conductivity within the inferred fracture zones are not constrained using this technique. The predominant orientations of the observed anisotropy are parallel and normal to the direction of maximum horizontal stress (northeast–southwest) and agree closely with previous fracture studies on core samples from the reservoir. Anisotropy anomalies are observed to correlate spatially with salt dissolution structures in the cap rock and overlying horizons as interpreted from 3D seismic cross sections.

Research on Sealing of Cap Rock of D Block in Xushen Gas Field

2020 ◽  
Author(s):  
T. Gao ◽  
P. Shu ◽  
H. Wang ◽  
C. Gu ◽  
X. Wang ◽  
...  
Keyword(s):  
Gas Field ◽  
Cap Rock

scholarly journals The History of Archaeological Investigations at The Jamestown Mound Site (41SM54), An Archaeological Conservancy Preserve in Smith County, Texas

2007 ◽  
Author(s):  
Timothy K. Perttula
Keyword(s):  
The Other ◽  
Archaeological Research ◽  
Archaeological Record ◽  
East Texas ◽  
Open Area ◽  
Circular Pattern ◽  
Pine Tree ◽  
History Of ◽  
Clay Cap ◽  
Sabine River

The Jamestown Mound site (41SM54) is an Archaeological Conservancy (TAC) preserve in northern Smith Country, Texas in the northeastern part of the state. The Jamestown site is one of the largest Caddo mound centers in East Texas, with seven recorded mounds and an associated village area of unknown extent and internal complexity. It is also one of the four premier mound centers in the Sabine River basin, the other three being Hudnall-Pirtle (41RK4), a TAC preserve, Pine Tree Mounds (41HS15), also a TAC preserve as of 2006, and Boxed Springs (41UR30), and was obviously an important civic and ceremonial center for the prehistoric Caddo peoples that lived there and in surrounding communities. Unfortunately, at the present time very little is known about the archaeological record preserved at the Jamestown site, or the exact locations of several of the smaller mounds on the preserve. Here, I summarize the history of archaeological research at the Jamestown site. This article is intended to be a companion piece to the report to be submitted to the TAC on the results of on-going remote sensing activities at the Jamestown preserve. The Jamestown preserve covers approximately 18 acres of pasture divided into two tracts by a north-south running fence. It is a large prehistoric Caddo mound center, with multiple mounds, roughly arranged in a circular pattern, with an open area (or plaza) between the mounds. The largest mound (Md. A) (measuring ca. 43 m in diameter and 4 m in height, is situated in the southwestern side of the circle of mounds. Mounds B-E (15-20 m in diameter and 40 cm-1 m in height) are probably mounds built over houses with a clay floor and a clay cap. The exact locations of Mounds D and E within the TAC preserve are not currently known. Md. A is known to have two levels of burned structural remains in the upper mound fill.

scholarly journals Temperature-Driven Hydrocarbon Generation-Expulsion and Structural Transformation of Organic-Rich Shale Assessed by in situ Heating SEM

2021 ◽  
Vol 9 ◽  
Author(s):  
Yuan Yuan ◽  
Jijin Yang
Keyword(s):  
Structural Changes ◽  
Fracture Network ◽  
Reservoir Rock ◽  
Continuous Heating ◽  
Hydrocarbon Generation ◽  
Sem Images ◽  
Cap Rock ◽  
Hydrocarbon Expulsion ◽  
The Relationship

Mud shale can serve as source or cap rock but also as a reservoir rock, and so the development of pores or cracks in shale has become of great interest in recent years. However, prior work using non-identical samples, varying fields of view and non-continuous heating processes has produced varying data. The unique hydrocarbon generation and expulsion characteristics of shale as a source rock and the relationship with the evolution of pores or cracks in the reservoir are thus not well understood. The present work attempted to monitor detailed structural changes during the continuous heating of shale and to establish possible relationships with hydrocarbon generation and expulsion by heating immature shale samples while performing in situ scanning electron microscopy (SEM) imaging and monitoring the chamber vacuum. Samples were heated at 20°C/min from ambient to 700°C with 30 min holds at 100°C intervals during which SEM images were acquired. The SEM chamber vacuum was found to change during sample heating as a consequence of hydrocarbon generation and expulsion. Two episodic hydrocarbon expulsion stages were observed, at 300 and 500°C. As the temperature was increased from ambient to 700°C, samples exhibited consecutive shrinkage, expansion and shrinkage, and the amount of structural change in the vertical bedding direction was greater than that in the bedding direction. At the same time, the opening, closing and subsequent reopening of microcracks was observed. Hydrocarbon generation and expulsion led to the expansion of existing fractures and the opening of new cracks to produce an effective fracture network allowing fluid migration. The combination of high-resolution SEM and a high-temperature heating stage allowed correlation between the evolution of pores or cracks and hydrocarbon generation and expulsion to be examined.

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