Performance of Oilwell Cementing Compositions in Geothermal Wells

1979 ◽  
Vol 19 (04) ◽  
pp. 233-241 ◽  
Author(s):  
J.P. Gallus ◽  
L.T. Watters ◽  
D.E. Pyle
Keyword(s):  
Service Life ◽  
Field Experiments ◽  
Testing Procedure ◽  
Laboratory Evaluation ◽  
Imperial Valley ◽  
Geothermal Well ◽  
Geothermal Fluids ◽  
Geothermal Wells ◽  
Geothermal Environments ◽  
Cement Strength

Abstract Just a few years ago, there existed a great uncertainty regarding the durability of oilwell cements in geothermal wells. Limited, and at times apparently unreliable, information suggested that conventional well cements may not be sufficiently resistant to geothermal well fluids and temperatures for the expected 20- or 30-year service life of the average geothermal well. Therefore, we began to investigate the performance of numerous oilwell cementing compositions in actual geothermal environments.Duplicate samples were exposed to actual geothermal well temperatures and fluids in the Baca, NM, and Imperial Valley, CA, geothermal fields for periods of up to 1 year.A novel testing procedure for geothermal cements was developed and successfully applied in these experiments. Laboratory evaluation of the exposed samples measured the durability of various compositions.The work indicated that some oilwell cements apparently can be rendered sufficiently resistant to geothermal well conditions for the service life of a geothermal well. Introduction The research completed and reported here was prompted primarily by uncertainty about the durability of any cement to be applied in geothermal wells with bottomhole temperatures ranging from 400 to 750 deg. F (204 to 399 deg. C) or produced flashing brine. The required well-service life ranged from 20 to 30 years. Several problems existed. First, the literature contained little applicable information about high-temperature hydrothermal cement chemistry. Prediction of the service life of cements in geothermal environments on the basis of known cement chemistry clearly was impossible. Prediction was of vital concern to operators responsible for safe, as well as competent, geothermal wells, particularly when serious cement-strength retrogression and deterioration generally was known to occur at elevated temperatures.Second, results of an early field test [which exposed samples of oilwell cements as 2-in. (5-cm) precured cement cubes to 600 deg. F (316 deg. C) brine in a geothermal well for periods up to 1 year] strongly suggested that even the three best cementing compositions tested might deteriorate to less than minimum acceptable compressive strengths within 3 to 9 years during geothermal well service. Other field experiments with oilwell cements in contact with produced geothermal fluids also yielded information showing extremely rapid (30- to 60-day) cement deterioration in strength and permeability. Thus, an API Class G cement (without silica) completely disintegrated (to granular size) in 30 days when exposed to 460 deg. F (238 deg. C) steam. Significantly we found that this sample contained (on X-ray diffraction analysis) both dicalcium silicate hydrate and large amounts of calcium hydroxide and carbonate. In another sample of this cement, compressive strength degraded by 77% from 5,050 to 1,150 psi (34.8 to 7.93 MPa) and permeability increased from 0.012 to 8.3 md in 60 days of aging in a produced geothermal brine of only 320 deg. F (160 deg. C) temperature. SPEJ P. 233＾

scholarly journals A Novel Experimental Investigation of Cement Mechanical Properties with Application to Geothermal Wells

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3426 ◽  
Author(s):  
Catalin Teodoriu ◽  
Mi Chin Yi ◽  
Saeed Salehi
Keyword(s):  
Oil And Gas ◽  
Field Measurements ◽  
Strength Properties ◽  
Interfacial Bonding ◽  
Free Movement ◽  
Geothermal Well ◽  
Well Integrity ◽  
Well Design ◽  
Geothermal Wells ◽  
Cement Strength

Geothermal well integrity has proven to be of high importance, especially because the geothermal life span is expected to be longer than that of conventional oil and gas wells. Recent studies have demonstrated that cement-casing interfacial bonding is a classical well failure in such wells, but field measurements do not correlate with the simulations. We believe that this discrepancy is due to limitations of the simulation itself, which in most cases assumes a free movement of the casing after the interfacial bonding has been exceeded. Since the casing is cemented using a complex hardware package such as centralizer and other cementing components, the free movement of the casing is only possible when no-cement exists behind the casing. This paper proposes a novel experimental method to understand cement strength properties other than the standardized unconfined cement strength (UCS). The novel setup allows the measurement of interfacial bonding strength between cement and casing and the pure cement shear strength. The later becomes an important parameter as the interaction between casing couplings and cement will show. In the past, standard cement bending tests were designed to measure cement shear, but the value obtained from such tests is not relevant for the geothermal in situ casing-cement interaction, and thus the need for a new testing method arose. The new method is capable to mimic the interaction between the casing connection edges and the cement. We believe that the results presented within this paper will help engineers to validate their numerical simulations and to optimize the geothermal well design which will result in the increase of the well integrity for the life of the geothermal well.

scholarly journals Cement / rock interaction in geothermal wells

2021 ◽  
Author(s):  
◽  
João Ricardo Marques Conde da Silva
Keyword(s):  
Driving Forces ◽  
Volcanic Rocks ◽  
Drilling Mud ◽  
Rock Permeability ◽  
Rock Interaction ◽  
Geothermal Wells ◽  
Physical Interactions ◽  
Geothermal Environments ◽  
Cement Formulation ◽  
The Way

<p>One of the main issues associated with the exploitation of geothermal energy is the durability of the cement that is used downhole to cement the steel casing to the formation. Cement durability can have a major impact on the lifetime of geothermal wells, which do not usually last as long as desirable. The cement formulations used in the construction of geothermal wells are designed to provide mechanical support to the metallic well casings and protect them against the downhole harsh environment, which often leads to corrosion. This research is focused on the way that these formulations interact with the surrounding rock formation in geothermal environments, and aims to understand whether these are likely to affect the cement durability and, consequently, the geothermal well lifetime. The experimental work in this thesis consists of examining the changes in the interfacial transition zone (ITZ) that forms between geothermal cements and the volcanic rocks, after hydrothermal treatment. Holes were drilled in blocks of volcanic rocks and cement slurries with distinct formulations were poured into the cavities. The assemblages were autoclaved under typical geothermal conditions. The main variables under study were the cement formulation, the temperature of curing (150°C and 290°C), the presence of drilling mud, CO₂ exposure and the type of rock. The results show that with all the Portland cement based systems a series of chemical reactions occur at the interface between the cement and the rock, the ITZ, where migration of Ca²⁺ and OH⁻ ions occurs from the cement into the rock pores. These reactions are ongoing, which occur faster during the first days/few weeks of curing, mostly driven by physical process of cement movement into the rock, followed by a slower second stage, controlled mostly by chemical driving forces. This work highlights the interdependence between the chemical and physical interactions between geothermal cements and volcanic rocks which are complex. Variables such as temperature and time of curing and silica addition affect the cement phases that form, while the amount of amorphous silica and rock permeability dictate the extent of rock interaction. The presence of carbon dioxide influences the extent of rock/cement interaction and this can be controlled by the rock permeability and cement formulation. Consequently, most of the above mentioned variables were found to have an impact on the geothermal cement durability, which depends on the way these factors are combined.</p>

scholarly journals Unit Quaternion Description Method for Detecting High-Temperature Geothermal Well Drilling Conditions

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Hongyan Li ◽  
Pengtao Wang ◽  
Bin Liu ◽  
Xianyu Zhang ◽  
Hai Huang ◽  
...  
Keyword(s):  
High Temperature ◽  
Detection Efficiency ◽  
Principal Component ◽  
Kernel Principal Component Analysis ◽  
Unit Quaternion ◽  
Well Drilling ◽  
Geothermal Well ◽  
Geothermal Wells ◽  
Time Required ◽  
Drilling Conditions

When the typically utilized method for detecting the drilling conditions of high-temperature geothermal wells is applied, the detection takes a long time, the detection results are inconsistent with the actual conditions, and there are problems such as low detection efficiency and large detection deviation. Therefore, a method for detecting the drilling conditions of high-temperature geothermal wells described by a unit quaternion is proposed. Based on quaternion theory, the quaternion model of the position and attitude is constructed to obtain the drilling attitude. According to the analysis results and the basic principle of kernel principal component analysis, a model is built to realize the detection of high-temperature geothermal well drilling conditions. The experimental results show that in many iterations, the time required is stable and lower than that of other comparison methods, and the detection errors are all lower than 10%. The proposed method has high detection efficiency and low detection errors.

Obtaining Zonal Isolation in Geothermal Wells

2021 ◽  
Author(s):  
Allam Putra Rachimillah ◽  
Cinto Azwar ◽  
Ambuj Johri ◽  
Ahmed Osman ◽  
Eric Tanoto
Keyword(s):  
Best Practices ◽  
Oil And Gas ◽  
Lessons Learned ◽  
Free Fluid ◽  
High Heating Rate ◽  
Lost Circulation ◽  
Geothermal Well ◽  
Geothermal Wells ◽  
Zonal Isolation ◽  
Primary Cementing

Abstract Cementing is one of the sequences in the drilling operations to isolate different geological zones and provide integrity for the life of the well. As compared with oil and gas wells, geothermal wells have unique challenges for cementing operations. Robust cementing design and appropriate best practices during the cementing operations are needed to achieve cementing objectives in geothermal wells. Primary cementing in geothermal wells generally relies on a few conventional methods: long string, liner-tieback, and two-stage methods. Each has challenges for primary cementing that will be analyzed, compared, and discussed in detail. Geothermal wells pose challenges of low fracture gradients and massive lost circulation due to numerous fractures, which often lead to a need for remedial cementing jobs such as squeeze cementing and lost circulation plugs. Special considerations for remedial cementing in geothermal wells are also discussed here. Primary cement design is critical to ensure long-term integrity of a geothermal well. The cement sheath must be able to withstand pressure and temperature cycles when steam is produced and resist corrosive reservoir fluids due to the presence of H2S and CO2. Any fluid trapped within the casing-casing annulus poses a risk of casing collapse due to expansion under high temperatures encountered during the production phase. With the high heating rate of the geothermal well, temperature prediction plays an important part in cement design. Free fluid sensitivity test and centralizer selection also play an important role in avoiding mud channeling as well as preventing the development of fluid pockets. Analysis and comparison of every method is described in detail to enable readers to choose the best approach. Massive lost circulation is very common in surface and intermediate sections of geothermal wells. On numerous occasions, treatment with conventional lost-circulation material (LCM) was unable to cure the losses, resulting in the placement of multiple cement plugs. An improved lost circulation plug design and execution method are introduced to control massive losses in a geothermal environment. In addition, the paper will present operational best practices and lessons learned from the authors’ experience with cementing in geothermal wells in Indonesia. Geothermal wells can be constructed in different ways by different operators. In light of this, an analysis of different cementing approaches has been conducted to ensure robust cement design and a fit-for-purpose cementing method. This paper will discuss the cementing design, equipment, recommendations, and best available practices for excellence in operational execution to achieve optimal long-life zonal isolation for a geothermal well.

scholarly journals Drill Stem Steels for Use in Geothermal Environments

1981 ◽  
Vol 103 (2) ◽  
pp. 159-165
Author(s):  
R. Salzbrenner
Keyword(s):  
Weight Percent ◽  
General Corrosion ◽  
Corrosion Properties ◽  
Drill Stem ◽  
Geothermal Fluids ◽  
Duplex Steel ◽  
Drilling Operations ◽  
Geothermal Environments ◽  
Geothermal Drilling ◽  
Carbon System

Steels which are used in drill stem for conventional drilling have been selected primarily to satisfy certain static strength requirements and cost considerations. As the environments in which drilling is performed become more severe (e.g., in geothermal fluids) additional considerations must be given to the design of alloys which are resistant to general corrosion, stress corrosion, and corrosion fatigue. General design considerations for steel alloys which should provide an enhanced resistance to geothermal drilling operations are presented. These considerations include discussion of the chemistry and metallurgical substructure, and how their variation affects the mechanical and corrosion properties of steel used for drill stem applications. A duplex ferritic-martensitic steel has an advantageous combination of compositional and microstructural features which should lead to improved chemical resistance (particularly to hydrogen sulfide) as well as provide a good combination of strength and toughness properties. This duplex steel is based on the iron-2.0 weight percent silicon-0.1 weight percent carbon system, and offers the potential of enhanced performance in geothermal drilling as well as low alloy cost.

scholarly journals How Can Temperature Logs Help Identify Permeable Fractures and Define a Conceptual Model of Fluid Circulation? An Example from Deep Geothermal Wells in the Upper Rhine Graben

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Jeanne Vidal ◽  
Régis Hehn ◽  
Carole Glaas ◽  
Albert Genter
Keyword(s):  
Upper Rhine Graben ◽  
Fluid Circulation ◽  
Geothermal Heat ◽  
Geothermal Fluids ◽  
Rhine Graben ◽  
Sensitive Tool ◽  
Geothermal Wells ◽  
Different Temperatures ◽  
Drilling Operations ◽  
Upper Rhine

Identifying fluid circulation in fracture zones (FZs) is a key challenge in the extraction of deep geothermal heat from natural reservoirs in the Upper Rhine Graben. This study focuses on permeable FZs present within the granitic basement penetrated by deep geothermal well GPK-1 at Soultz and GRT-1 and GRT-2 at Rittershoffen (France). The various temperature (T) log datasets acquired from these wells during production and at equilibrium, with the associated flow logs, allow for the unique opportunity to interpret fluid circulation at the borehole scale. All permeable FZs identified by permeability indicators measured during drilling operations and from image logs spatially coincide with positive or negative T anomalies observed in the T logs during production and/or at equilibrium. However, within the FZs, partially open fractures act as narrower paths for circulation at different temperatures. These temperatures can even be estimated with confidence if the associated flow log is available. The polarity of the T anomalies correlates with the state of equilibrium of the well and thus can change over the well history. During production, the temperature of the water inflow through the fractures can be estimated relative to the mixture of water circulating below the fractures. At thermal equilibrium, the water temperature is estimated with respect to the temperature of the surrounding rock formation. Because temperature fluxes and geothermal fluids are intimately linked, T logs are a useful, reliable, and very sensitive tool to localize the inflow of geothermal water through FZs.

MICROEARTHQUAKE INVESTIGATION OF THE MESA GEOTHERMAL ANOMALY, IMPERIAL VALLEY, CALIFORNIA

Geophysics ◽  
1977 ◽  
Vol 42 (1) ◽  
pp. 17-33 ◽  
Author(s):  
Jim Combs ◽  
David Hadley
Keyword(s):  
Vertical Component ◽  
Surface Expression ◽  
High Gain ◽  
Strike Slip ◽  
Imperial Valley ◽  
Natural Period ◽  
Near Surface ◽  
Geothermal Fluids ◽  
First Motion ◽  
Motion Studies

Microearthquakes associated with the Mesa geothermal anomaly were recorded for five weeks during the summer of 1973 using an array of six portable, high‐gain seismographs equipped with vertical‐component 1-sec natural period seismometers. Background seismicity of the area is thus determined prior to development for geothermal power and water. The local seismicity changed considerably over the recording period. Most daily activity was characterized by only one or two potentially locatable events, while two microearthquake swarms of two‐ and three‐day duration included as many as 100 or more distinct local events per day. Hundreds of small events (nanoearthquakes), some clustered in swarms, were recorded by each seismograph; however, most were not detected on four or more seismograms so that hypocentral locations usually could not be determined. Locations were determined for 36 microearthquakes having epicenters situated in the [Formula: see text] areal extent of the geothermal anomaly. Focal depths ranged from near‐surface to about 8 km. More than half of the located events have hypocenters greater than the 4.0 km which is approximately the depth to crystalline basement. Stress associated with the Mesa geothermal anomaly is relieved by a combination of continuous microseismic activity and intermittent microearthquake swarms. Based on the results of the present study, a new right‐lateral strike‐slip fault, the Mesa fault, was defined. First motion studies indicate strike‐slip faulting although there is no surface expression of the fault. The northwest‐southeast trending Mesa fault is an active fault functioning as a conduit for rising geothermal fluids of the Mesa geothermal anomaly. This investigation is another demonstration that geothermal areas are characterized by enhanced microearthquake activity.

Storage Capacity of Geothermal Resources in Gaoling Group over the Eastern Half of Xi’an Depression

2012 ◽  
Vol 512-515 ◽  
pp. 894-899
Author(s):  
Yun Feng Li ◽  
Bo Li ◽  
Yao Guo Wu ◽  
Jiang Xia Wang ◽  
Zhong Hua Xu ◽  
...  
Keyword(s):  
Geothermal Energy ◽  
Storage Capacity ◽  
Geothermal Reservoir ◽  
Geothermal Resources ◽  
Water Storage Capacity ◽  
Calculation Region ◽  
Geothermal Fluids ◽  
Distribution Parameters ◽  
Geothermal Wells ◽  
Element Method

Weighted element method is proposed in this paper to improve the accuracy of calculating storage capacity of geothermal reservoirs. By making full use of all geothermal wells in the calculation region，this method had been proposed by the author in 2011,which is defined by every three neighboring geothermal wells. The calculation region is divided into many calculation elements. As a result, the entire calculation region of the distribution parameters is discretized into independent in each element with lumped parameters. The arithmetic mean of three-node parameters in each element is used as the lumped parameter, and the block with the same set of parameters is divided into calculation regions as small as possible. The effect of one element as well as its parameters in the entire.Calculation region depends on the weight of the area of this element in the whole calculation area. The weighted element method can be used to calculate the volumetric water storage capacity of geothermal fluids, elastic release storage capacity, geothermal storage capacity of volume water, geothermal energy storage capacity of elastic releasing water, geothermal storage capacity of geothermal reservoir rocks for each element, respectively. The storage capacities of various elements and the entire calculation regions can be calculated with superposition. The proposed approach was used to calculate the storage capacity of geothermal resources in Gaoling Formation of Xi’an Depression, in which data of 57 existing geothermal wells were available. If the geothermal energy recovery is set at 10% and the exploitation remains stable, the geothermal energy contained in the geothermal reservoir can be extracted for more than 7,000 years. Under the current conditions of exploitation technology, the actual geothermal energy that can be effectively exploited and used is 1915.6025×109kcal, which is equivalent to standard coal of 27.36575×104t.

scholarly journals A Nonradioactive Replacement for the Sodium-24 Tracer in Turbine Performance Tests

1984 ◽  
Author(s):  
Patricia C. Irwin ◽  
Thomas H. McCloskey
Keyword(s):  
Power Plants ◽  
Method Development ◽  
Complex Analysis ◽  
Field Tests ◽  
Testing Procedure ◽  
Ease Of Use ◽  
Laboratory Evaluation ◽  
Fossil Plants ◽  
Fossil Plant ◽  
Blow Down

In the past, expensive measuring devices were used to determine performance and efficiency on nuclear turbine cycles. More recently, sodium-24 replaced these devices because of the reduced cost, increased accuracy and improved precision. While radioactive sodium-24 has significant advantages, it brings with it several disadvantages such as: 1. limited useful working time, 2. exposure of testing personnel to ionizing radiation, 3. limited availability, 4. the need for government licensing which for all practical purposes precludes its use in fossil plants, 5. unacceptable radioactive release to the environment during boiler blow-down, 6. complex analysis procedure. Thus, a nonradioactive replacement for sodium-24 has become economically desirable as well as necessary from the ease of use point of view. In this paper, the procedure for choosing a nonradioactive replacement tracer will be discussed with reference to the criteria needed to be satisfied for an adequate tracer e.g., a suitable and sensitive analytical detection technique that would be already available to power plants. Necessary refinements to the sodium-24 testing procedure will also be discussed as well as a unique means of preconcentrating the tracer prior to analysis. The laboratory evaluation and method development to be discussed in the paper was funded by EPRI. The potential applications for the new tracer, which include all sodium-24 uses, will be noted. These uses include, but are not limited to component performance, heater leakage, and moisture calculations. Because federal licensing of the nonradioactive tracer is not necessary, tests in a fossil plant are possible and will also be discussed. The completed laboratory experiments indicate high promise for success in actual field tests which are scheduled for mid-1984 for fossil plant testing, and mid-1985 for nuclear station testing.

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