Pack Off Research Articles

High Performance Aqueous Fluids in Deepwater Operation

An exploration drilling in Gambia deepwater with water depth of 965m. well total depth drilled at measured depth 3,457m, the maximum inclination angle 34.6º and the horizontal section depth 1000m. The top-hole section was drilled with seawater and Guar GUM Sweep and the conductor casing set at 1053m. After the 26’’ hole was drilled with seawater and GUAR GUM sweep at TD the well was displaced to pad mud (KCl/polymer Mud) the 20’’ casing run and cemented. The intermediate and landing section was drilled with High Performance Water-based mud which was provide by one of leading servicing provider. This is where it was first deployed in Deepwater operation in West Africa (Gambia) and it shows good cutting and shale inhibitive performance, good hole cleaning, and wellbore stability, it allows the MWD tools to performed at high ROP, the rheological properties were stable with little treatment, the gives good lubrication and good cutting carrying to surface. According to Pearson, J.R.A [1], that the important rheological requirements are that they should have a low an apparent viscosity as possible, consistent with drilled cutting back to the surface during circulation.
 In deepwater operation we may encountered some extremely reactive formations that can incur lot of cost, well lost hole pack off and lost of drilling tools (BHA) which will require sidetrack. Also, with the glamour for the clean energy in the world, there are a lot of environmental restriction now and high cost of waste disposal. This high-performance Water based mud is an option to address the above concerns much attractive in drilling operation.
 In this study, the rheological preparties of the mud will be compare with Oil based mud to see the way they performed downhole. The hole cleaning ability and the number of cutting waste that will be generated which will translate to the cost of disposal.
 This result show that high performance water-based mud is more effective in term of cost, solved environmental concern and performed as oil – based mud that is wildly used in the region.

Solutions to increase the C-2P well production performance at X oil field, Block 09-2

The well C-2P had its first oil production in July 2008, the initial production rate is 3,000 barrels/day. Due to the reservoir pressure depletion in 2017-2018, the well faced difficulties in kicking off to open the well for production. In November 2018, when the C-5PST2 well was put into production, the C-2P well was not produced by natural flowing. The kicking off has been attempted many times but the well still won't flow. The main reason the well couldn’t flow is due to low reservoir pressure which has not enough energy to push all the fluid in the well to the surface after each well shutdown. The flow assurance study shows, at the reservoir pressure of 3,000 Psi, and tubing head pressure of 950 Psi, the well can’t flow naturally. In addition, with the reservoir pressure of 3,000 psia and applying the gaslift injection rate of 1.0 MMscf/d, injection point at 3,030 mTVD, the well flowed. The continuous gaslift pump helps maintain the well's production in case the reservoir pressure drops even lower to 2,000 psi, and at the same time, optimizing the gaslift pump flow helps to increase the well production by 100-300 barrels of oil/day. When the reservoir pressure drops lower, it is necessary to lower the gaslift valve deeper to continue kicking off the well and maintain the well production performance. On the other hand, due to the lack of a gaslift valve for the original design of C-2P well so it's necessary to have gaslift tubing pack off in order to bring the well back to production, maintain stability and improve production. This paper, therefore, presents the results of the research on the solution to increase the production output of the C-2P well located in X oil field used gaslift valve combining with the tubing pack off. Results of the research on the application of solution show that the well's production output has increased significantly (0.354 million barrels) in the first year of applying the solution.

“In All Ages and All Churches”: Anti-Mormonism and the Making of Antebellum Evangelicalism

“In All Ages and All Churches”: Anti-Mormonism and the Making of Antebellum Evangelicalism

Investigation of Mud Related Wellbore Problems in Drilling Well-A in the Niger Delta Region

Wellbore instabilities due to mud related issues during well construction in the wetland Niger Delta region were analyzed, reviewing well A as a case study. Time distribution plots and activity break down summary were evaluated for the candidate well. From the analyses, drill bit and bottom hole assembly balling, largely due to soft sticky and reactive gumbo shale with high swelling and dispersive tendencies in the mud system, severe down hole losses, hole pack off, pipe stuck potentials and kicks are some likely mud related challenges often encountered drilling in the Niger Delta region. Consequent upon which there would be reduced rate of penetration, tight spot, increased torque and drag, as seen in well-A. The drilling fluids play pivotal roles in oil extraction processes as their type; design and formulation determine the ultimate success of the entire drilling operation and overall production performance of the well. A poorly designed mud system may trigger wellbore instability that could lead to non-productive time, loss of drilling equipment, even loss of the entire well, kick and blowout scenarios due to loss of primary and secondary barriers. Formation damage may occur, which ultimately leads to reduction in permeability and poor well performance,

History of failures in energizing pack off in the Brazilian Pre-Salt: a multidisciplinary approach

History of failures in energizing pack off in the Brazilian Pre-Salt: a multidisciplinary approach

Experimental investigation of cuttings transportation in deviated and horizontal wellbores using polypropylene–nanosilica composite drilling mud

The experience acquired in the field showed that poor cuttings transportation results in several drilling problems, such as pipe sticking, undue torque and drag, hole–pack off, or lower than projected drilling performance. In this study, complex water–based mud (WBM) formulated with polypropylene–nanosilica composite (PP–SiO2 NC) and partially hydrolyzed polyacrylamide (PHPA), a drag–reducing agent were used to examine cuttings transferring efficiencies (CTEs). The examination focused on the impact of diameters of cuttings (between 0.50 and 4.00 mm), hole angles (45, 60, 75, 90°), mud velocities (between 0.457 and 1.80 m/s) and different concentrations (0.4, 0.5, 0.8 and 1.2 ppb) of PP–SiO2 NC and PHPA. A field–oriented cuttings transport flow loop of dimensions (69.85 mm × 26.67 mm, 6.07 m–long annulus) was constructed to determine the CTEs of the drilling muds. Results showed that smallest cuttings were easiest to remove when mud velocities of 0.457, 0.630, 0.823 and 0.960 m/s were used, but when the velocity increased to 1.80 m/s, the transport of largest cuttings became the easiest. Results also confirmed that PP–SiO2 NC muds are more capable of transferring cuttings than PHPA mud samples with or without pipe rotation speed due to increased colloidal forces that increase the interaction between cuttings and PP–SiO₂ NC particles. Rotation of drill pipe and an increase in mud velocity will effectively increase the drag effects, which will lead to increased CTE. Hole angle 45° was the most difficult inclination in the cuttings transport process due to the higher settling tendency of cuttings on the low side of the hole. The application of complex WBM with PP–SiO2 NC showed promising attributes in a cuttings transport process.

Stability of production section in south Iraq

The drilling of the production section in the development wells in South Iraq could face numerous problems related to the partial or total losses, flow of sulphurous water, significant change in pore pressure along the wellbore, tight hole and caving among others. One of the main issues observed in several fields across South Iraq during well construction is the stability of in the production section of wellbore (especially in the shale formations). The instability of the open hole led to time consuming incidents related to an inability to run open hole logs to the wells total depth. Additional time has also been spent on wiper trips, reaming and backreaming, and on incidents related to hole pack off and stuck pipe. To solve the problem several steps were taken starting with the creation of a mechanical earth model which identified the main problematic formations presented by shale and the possible root causes of instability. This involved core characterization analysis including X-ray diffraction, cation exchange capacity and thin section analysis were performed to identify the structure of the shale. In addition the fracture development tests were performed on the samples of core and from this the main root causes of instability were identified. Based on the theoretical research and the laboratory tests new drilling fluid formulation together with best drilling practices were proposed that would allow the elimination of the problem due to the stability of the wellbore in the shale formations.

Prediction of Rock Strength using Drilling Data and Sonic Logs

Uniaxial test (also called unconfined compression test) is one of most important tests used to measure rock strength. It is critical to obtain the rock strength parameters along the wellbore. Awareness of rock strength could better control drilling problems such as pipe sticking, tight hole, collapse, pack off and sand production. Rock strength also controls the drilling rate of penetration (ROP). The calculations of uniaxial Compressive Strength (UCS) are based on a simplified version of the ROP model proposed for tricone bits. The purpose of this research was to predict the uniaxial compressive strength based on sonic logs as a function of sonic travel and formation porosity. For obtaining continuous log strength along the wellbore in Ahwaz oilfield, quantitative relationships were developed between UCS and sonic travel time as well as UCS and both of sonic travel time and formation porosity. They actually are the outcome of regression analysis that resulting relationships are very practical and most often are specified by the researcher to the region of study. In this work, a larger well segment has been analyzed which there is no information break throughout the segment and it is investigated continuously. Using this approach, 3D model was a better predictor of uniaxial compressive strength than obtained equations related to transient time and results have also confirmed that the use of an recommended equations in this study can reduce drilling costs significantly.

A Feasibility Investigation of Hydra-jet Fracturing in Deep Wells

With the exploration and discovery of deep low-permeability reservoirs in China, fracturing operations in high-temperature and deep wells are more and more important. Conventional fracturing treatment has some difficulties, such as high bottomhole fracturing pressure, high pump pressure, and malfunction of packer resulting from high temperature, etc. This article presents hydra-jet fracturing, a unique, relatively new stimulation technology that could greatly decrease bottomhole fracturing pressure, and pack off fracture interval using hydrodynamic energy without any packers, implementing fixed directional multilayer fracturing with a one-trip fracturing string. These technical advantages of hydra-jet fracturing are conducive to deep wells fracturing.

Case Study: Drillstring Failure Analysis and New Deep-Well Guidelines Lead to Success

Summary Three drillstring fatigue failures occurred while drilling two deep wells below 16,500 ft true-vertical depth (TVD) in the US midcontinent region. All the failures occurred across 2°/100 ft- to 3°/100 ft-dogleg severity (DLS) intervals from 6,000 to 8,000 ft. The well conditions (i.e., pipe condition and directional plan) were not significantly different from other deep wells in the area, which had not failed. A deep-well drillstring failure study was conducted, which included a review of drillstring-inspection reports, daily drilling reports, digital data, technical literature, and engineering analysis for the two wells. A cumulative fatigue analysis (CFA) modeling technique taking into account specific well conditions [i.e., wellbore geometry, rotary speed, rate of penetration (ROP), hook load, and drillstring configuration] was applied. The model indicated that drillstring failures would occur across shallow doglegs mainly because of high hang-down loads combined with slow ROP. The results of the study led to the development of new deep-well design criteria and implementation of new drilling guidelines. The new guidelines included the use of look-ahead CFA modeling when approaching drillstring endurance limits to minimize drillpipe-fatigue failures. Look-ahead CFA modeling and the new drilling guidelines were used on two subsequent deep wells in the area, leading to successful drilling to total depth (TD) of 18,000 ft TVD without failure. One of the wells had a 1.4°/100-ft DLS (calculated based on 100-ft survey spacing) at 1,500 ft, and drillpipe shuffling was required to prevent drillstring failure in the deep-hole section. The drillstring-fatigue failure prevention guidelines apply to deep wells drilled worldwide. Introduction BP America, Inc. experienced three high-load cyclic fatigue tube failures while drilling in the US midcontinent region's deep Anadarko basin. All of the failures occurred within a four-month period on two wells drilled by different rigs. The three fatigue failures occurred in the highest shallow dogleg interval of the wells, and all three failures were in the inclination-angle dropping section of the well. In Well A, poor mud properties caused the hole to pack off, leading to a heat-related tensile failure of a crossover in the bottomhole assembly (BHA). An unsuccessful fishing job for the remaining BHA led to a sidetrack. The sidetrack around the fish created shallow doglegs and led to the two drillpipe-fatigue failures in Well A. Shallow directional walk problems combined with a small directional target created shallow doglegs in Well B. The well scope was also changed at TD to drill 375 ft deeper. Mud circulation was lost, and the drillstring was rotated without circulation while building mud volume. Well B subsequently experienced a fatigue failure while pulling out of the hole at TD of 16,628 ft. After these failures occurred, a comprehensive study was performed to understand why these two wells experienced drillpipe failures while other area wells with similar conditions did not experience a failure. The study included a review of drillpipe-inspection reports, daily drilling reports, digital drilling recorder data, and engineering analysis.

Ecological and biogeographic relationships of class Flavobacteria in the Southern Ocean

The abundance, spatial distribution and diversity of class Flavobacteria were investigated in the Southern Ocean euphotic zone across a latitudinal transect and in the ice pack off Eastern Antarctica. Surface seawater samples filter-fractionated into 0.8 μm particulate and 0.2 m planktonic fractions were investigated with different molecular techniques. The abundance of particle-associated Flavobacteria, ascertained with real-time PCR and DGGE band analysis using Flavobacteria-specific primers, was found to be significantly higher in Polar Front Zone (PFZ) and Antarctic Zone (AZ) water samples than in nutrient limited Temperate Zone (TZ) and Sub-Antarctic Zone (SAZ) waters. Abundance of particle-associated Flavobacteria correlated positively with seawater chlorophyll a and nutrient concentrations, suggesting that increased Flavobacteria abundance may relate to enhanced primary production in the PFZ and AZ. This is supported by comparison of DGGE profiles that demonstrated significant differences in the total Flavobacteria community structure and 16S rRNA gene diversity between samples from the PFZ and AZ and those from TZ and SAZ. Sequence analysis revealed a broad diversity amongst class Flavobacteria in the Southern Ocean with several Flavobacteria clades detected in PFZ and AZ waters not detected in TZ and SAZ waters that putatively represent psychrophilic taxa. Sequence data included a large, so far uncultivated, cosmopolitan phylogenetic clade (“DE cluster 2”) that is distributed throughout the Southern Ocean.

Double Talk And Double Vision: Creating Science Research Policy On Human Cloning

Since the winter of 1997, when the world became aware that a sheep named Dolly had been successfully cloned, the discourse about how this idea might be used to make humans instantly became theword for all we adore and all we disdain about our future. After two decades in which ethicists wrung their hands at the prospect and were dismissed as alarmist (since “cloning mammals was not really possible”), suddenly the bleating, furry evidence appeared before us. Dolly became the symbol of a science gone out of control and deeply in need of public limits. Then, the fierceness and intensity of the arguments and the books rapidly generated that called for a return to a bucolic, unhampered “Nature” caused a correspondent alarm for the science community. How could research integrity and freedom to inquire be protected from policy that threatened not only to defund research but also to pack off offending investigators to hard time: ten-year prison terms and millions in fines? One goodway to begin to answer this question is to carefully look at the language of the debate on cloning over the past six years—a genre of immediate historical review. By such a careful reading, one can see how “cloning” becomes one large metaphor for the entire gesture of science. Such a history, read via the words of both the testimony of the participants and the final text of the major documents themselves, suffers from its immediacy but is deepened by the ability of recent memory and fine-grained attention to detail. A pivotal event will only look pivotal when we read backwards in ten years, but with a science so swiftly moving, it is important to record every twist and turn in the debate. C ra f t i ng a C l o n i ng Pol i c y, by Andrea Bonnicksen, is the best example of such a careful historical review. A political scientist and long a thoughtful assessor of advanced reproductive techniques and technologies, Bonnicksen sets out two essential tasks. First, she reviews the step-by-step,month-by-month debates about human reproductive cloning from Dolly’s birth to, as promised in her title, the human embryonic stem cell debate up to the spring of 2002. (Hence, it is not her fault that large sections of the book were rendered instantly out of date by the shifts in legislation in California and other states that have occurred since then. The professor using this book in classes will have the chance to hand out the new California reports and give a great lecture about how rapidly policy changes when it must follow emerging science.) This history reminds us of the key arguments that were made in the first five years of debates about cloning and how the arguments shifted when it became clear that the technique of cloningmightwell be used to advance research in histocompatibility for tissue engineering using human embryonic stem cells. At stake in such a history are the long-defended ramparts of abortion policy—with banners from the Roe v. Wade error unfaded, still aloft. B o o k R e v i e w s

Foreigners

FOREIGNERS / Marcelle Martin THE DOOR OF the next hotel was open. A narrow carpet of light extended across the sidewalk, a sign Laurie took as a welcome. She said bonsoir and explained to the woman behind the desk that she wanted a single room. "How long do you plan to stay?" The woman spoke in precise, business-like French. Laurie wanted to hug her: at last she had found a hotel that wasn't full, at last she could sleep. "Just one night." "I'm sorry," the woman said. "Our rooms are full." "That's not true!" There was laughter from the lounge. Laurie noticed two men seated in armchairs. "Don't cry," one of them told her. "There are plenty of rooms for you in other hotels." She turned back to the clerk. "How many days must I stay in order to get a room?" "Je suis désolée." The woman pressed her lips together. She wasn't desolate at all. As Laurie walked out the door, the men made crude suggestions about how to find a room. Her cheeks burned, and she was conscious that her orange backpack marked her as a foreigner with no place to go. At the next corner, she sat down on the curb. The street was narrow and the buildings old, with shutters at every window. From the bank of the Seine, moving uphill block by block, she had been to every hotel in the Latin Quarter except the expensive ones with two or three stars on the metal plaques beside their doors. She slid the pack off her shoulders. Having been invited by the French government to live in France for a year, to work as an English assistant in a lycée, she had felt special when she arrived in Paris, privileged. Although she and Bill had had difficulties obtaining hotel rooms when they traveled in Europe two years ago during the height of the tourist season, she had thought it would be easy to find a room at the end of September. It had not occurred to her that on a Saturday night all the student foyers and inexpensive hotels would be full by nine o'clock. To ease the pain in her neck and shoulders, she rotated her head in a slow circle, her eyes closed. She imagined a bed, imagined herself between clean sheets, asleep. She wanted nothing more. "Qu'est qui ne va pas?" asked a voice with a heavy accent. She looked up and saw two African men, both wearing three-piece suits. The taller one repeated the question. She struggled to think again in French. "Nothing's wrong. Tm just tired." The Missouri Review · 233 "Can we help you?" "No," she said. "Thank you." "Why are you sitting here?" The taller man persisted. "We only want to help. Where do you come from?" "The United States." They did not understand. "America." "America! That's why you spoke to us. In your country you have Americans who are black like us." He spoke as though she had identified herself as a compatriot. "We're foreigners like you. We only want to help. What's wrong?" He seemed sincere, and that fact that he was not alone made her less suspicious of his motives. "I don't have a room to stay in," she admitted. "But there are so many hotels here." "They're all full." "Impossible. Come, we help you find a room." She hesitated, aching to turn her problem over to someone else. Apart from brief naps on the plane, she hadn't slept for a day and a half. It seemed as though it were the same day—a long day—on which she had woken up in Bill's bedroom in Washington. The same day on which she had kissed him goodbye in Union Station and taken a train to New York, kissed his hard mouth as though she might never have another chance. Even in the station he wouldn't promise to come over for Christmas, saying, "You never know what might happen." "I want a room just for myself." Laurie stood up beside the Africans. "You understand that, don't...